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linux-next/drivers/lightnvm/pblk-sysfs.c

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lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
/*
* Copyright (C) 2016 CNEX Labs
* Initial release: Javier Gonzalez <javier@cnexlabs.com>
* Matias Bjorling <matias@cnexlabs.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* Implementation of a physical block-device target for Open-channel SSDs.
*
* pblk-sysfs.c - pblk's sysfs
*
*/
#include "pblk.h"
static ssize_t pblk_sysfs_luns_show(struct pblk *pblk, char *page)
{
struct nvm_tgt_dev *dev = pblk->dev;
struct nvm_geo *geo = &dev->geo;
struct pblk_lun *rlun;
ssize_t sz = 0;
int i;
lightnvm: make geometry structures 2.0 ready Prepare for the 2.0 revision by adapting the geometry structures to coexist with the 1.2 revision. Signed-off-by: Matias Bjørling <m@bjorling.me> Reviewed-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-05 21:16:03 +08:00
for (i = 0; i < geo->all_luns; i++) {
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
int active = 1;
rlun = &pblk->luns[i];
if (!down_trylock(&rlun->wr_sem)) {
active = 0;
up(&rlun->wr_sem);
}
sz += snprintf(page + sz, PAGE_SIZE - sz,
"pblk: pos:%d, ch:%d, lun:%d - %d\n",
i,
rlun->bppa.g.ch,
rlun->bppa.g.lun,
active);
}
return sz;
}
static ssize_t pblk_sysfs_rate_limiter(struct pblk *pblk, char *page)
{
lightnvm: pblk: use exact free block counter in RL Until now, pblk's rate-limiter has used a heuristic to reserve space for GC I/O given that the over-provision area was fixed. In preparation for allowing to define the over-provision area on target creation, define a dedicated free_block counter in the rate-limiter to track the number of blocks being used for user data. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-05 21:16:13 +08:00
int free_blocks, free_user_blocks, total_blocks;
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
int rb_user_max, rb_user_cnt;
lightnvm: pblk: redesign GC algorithm At the moment, in order to get enough read parallelism, we have recycled several lines at the same time. This approach has proven not to work well when reaching capacity, since we end up mixing valid data from all lines, thus not maintaining a sustainable free/recycled line ratio. The new design, relies on a two level workqueue mechanism. In the first level, we read the metadata for a number of lines based on the GC list they reside on (this is governed by the number of valid sectors in each line). In the second level, we recycle a single line at a time. Here, we issue reads in parallel, while a single GC write thread places data in the write buffer. This design allows to (i) only move data from one line at a time, thus maintaining a sane free/recycled ration and (ii) maintain the GC writer busy with recycled data. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:27 +08:00
int rb_gc_max, rb_gc_cnt, rb_budget, rb_state;
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
lightnvm: pblk: use exact free block counter in RL Until now, pblk's rate-limiter has used a heuristic to reserve space for GC I/O given that the over-provision area was fixed. In preparation for allowing to define the over-provision area on target creation, define a dedicated free_block counter in the rate-limiter to track the number of blocks being used for user data. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-05 21:16:13 +08:00
free_blocks = pblk_rl_nr_free_blks(&pblk->rl);
free_user_blocks = pblk_rl_nr_user_free_blks(&pblk->rl);
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
rb_user_max = pblk->rl.rb_user_max;
rb_user_cnt = atomic_read(&pblk->rl.rb_user_cnt);
rb_gc_max = pblk->rl.rb_gc_max;
rb_gc_cnt = atomic_read(&pblk->rl.rb_gc_cnt);
rb_budget = pblk->rl.rb_budget;
rb_state = pblk->rl.rb_state;
lightnvm: pblk: redesign GC algorithm At the moment, in order to get enough read parallelism, we have recycled several lines at the same time. This approach has proven not to work well when reaching capacity, since we end up mixing valid data from all lines, thus not maintaining a sustainable free/recycled line ratio. The new design, relies on a two level workqueue mechanism. In the first level, we read the metadata for a number of lines based on the GC list they reside on (this is governed by the number of valid sectors in each line). In the second level, we recycle a single line at a time. Here, we issue reads in parallel, while a single GC write thread places data in the write buffer. This design allows to (i) only move data from one line at a time, thus maintaining a sane free/recycled ration and (ii) maintain the GC writer busy with recycled data. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:27 +08:00
total_blocks = pblk->rl.total_blocks;
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
return snprintf(page, PAGE_SIZE,
lightnvm: pblk: use exact free block counter in RL Until now, pblk's rate-limiter has used a heuristic to reserve space for GC I/O given that the over-provision area was fixed. In preparation for allowing to define the over-provision area on target creation, define a dedicated free_block counter in the rate-limiter to track the number of blocks being used for user data. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-05 21:16:13 +08:00
"u:%u/%u,gc:%u/%u(%u)(stop:<%u,full:>%u,free:%d/%d/%d)-%d\n",
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
rb_user_cnt,
rb_user_max,
rb_gc_cnt,
rb_gc_max,
rb_state,
rb_budget,
pblk->rl.high,
free_blocks,
lightnvm: pblk: use exact free block counter in RL Until now, pblk's rate-limiter has used a heuristic to reserve space for GC I/O given that the over-provision area was fixed. In preparation for allowing to define the over-provision area on target creation, define a dedicated free_block counter in the rate-limiter to track the number of blocks being used for user data. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-05 21:16:13 +08:00
free_user_blocks,
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
total_blocks,
READ_ONCE(pblk->rl.rb_user_active));
}
static ssize_t pblk_sysfs_gc_state_show(struct pblk *pblk, char *page)
{
int gc_enabled, gc_active;
pblk_gc_sysfs_state_show(pblk, &gc_enabled, &gc_active);
return snprintf(page, PAGE_SIZE, "gc_enabled=%d, gc_active=%d\n",
gc_enabled, gc_active);
}
static ssize_t pblk_sysfs_stats(struct pblk *pblk, char *page)
{
ssize_t sz;
sz = snprintf(page, PAGE_SIZE,
"read_failed=%lu, read_high_ecc=%lu, read_empty=%lu, read_failed_gc=%lu, write_failed=%lu, erase_failed=%lu\n",
atomic_long_read(&pblk->read_failed),
atomic_long_read(&pblk->read_high_ecc),
atomic_long_read(&pblk->read_empty),
atomic_long_read(&pblk->read_failed_gc),
atomic_long_read(&pblk->write_failed),
atomic_long_read(&pblk->erase_failed));
return sz;
}
static ssize_t pblk_sysfs_write_buffer(struct pblk *pblk, char *page)
{
return pblk_rb_sysfs(&pblk->rwb, page);
}
static ssize_t pblk_sysfs_ppaf(struct pblk *pblk, char *page)
{
struct nvm_tgt_dev *dev = pblk->dev;
struct nvm_geo *geo = &dev->geo;
lightnvm: simplify geometry structure Currently, the device geometry is stored redundantly in the nvm_id and nvm_geo structures at a device level. Moreover, when instantiating targets on a specific number of LUNs, these structures are replicated and manually modified to fit the instance channel and LUN partitioning. Instead, create a generic geometry around nvm_geo, which can be used by (i) the underlying device to describe the geometry of the whole device, and (ii) instances to describe their geometry independently. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:05:10 +08:00
struct nvm_addrf_12 *ppaf;
struct nvm_addrf_12 *geo_ppaf;
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
ssize_t sz = 0;
lightnvm: simplify geometry structure Currently, the device geometry is stored redundantly in the nvm_id and nvm_geo structures at a device level. Moreover, when instantiating targets on a specific number of LUNs, these structures are replicated and manually modified to fit the instance channel and LUN partitioning. Instead, create a generic geometry around nvm_geo, which can be used by (i) the underlying device to describe the geometry of the whole device, and (ii) instances to describe their geometry independently. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:05:10 +08:00
ppaf = (struct nvm_addrf_12 *)&pblk->ppaf;
geo_ppaf = (struct nvm_addrf_12 *)&geo->addrf;
sz = snprintf(page, PAGE_SIZE,
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
"g:(b:%d)blk:%d/%d,pg:%d/%d,lun:%d/%d,ch:%d/%d,pl:%d/%d,sec:%d/%d\n",
lightnvm: simplify geometry structure Currently, the device geometry is stored redundantly in the nvm_id and nvm_geo structures at a device level. Moreover, when instantiating targets on a specific number of LUNs, these structures are replicated and manually modified to fit the instance channel and LUN partitioning. Instead, create a generic geometry around nvm_geo, which can be used by (i) the underlying device to describe the geometry of the whole device, and (ii) instances to describe their geometry independently. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:05:10 +08:00
pblk->ppaf_bitsize,
ppaf->blk_offset, ppaf->blk_len,
ppaf->pg_offset, ppaf->pg_len,
ppaf->lun_offset, ppaf->lun_len,
ppaf->ch_offset, ppaf->ch_len,
ppaf->pln_offset, ppaf->pln_len,
lightnvm: normalize geometry nomenclature Normalize nomenclature for naming channels, luns, chunks, planes and sectors as well as derivations in order to improve readability. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:05:14 +08:00
ppaf->sec_offset, ppaf->sec_len);
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
sz += snprintf(page + sz, PAGE_SIZE - sz,
"d:blk:%d/%d,pg:%d/%d,lun:%d/%d,ch:%d/%d,pl:%d/%d,sec:%d/%d\n",
lightnvm: simplify geometry structure Currently, the device geometry is stored redundantly in the nvm_id and nvm_geo structures at a device level. Moreover, when instantiating targets on a specific number of LUNs, these structures are replicated and manually modified to fit the instance channel and LUN partitioning. Instead, create a generic geometry around nvm_geo, which can be used by (i) the underlying device to describe the geometry of the whole device, and (ii) instances to describe their geometry independently. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:05:10 +08:00
geo_ppaf->blk_offset, geo_ppaf->blk_len,
geo_ppaf->pg_offset, geo_ppaf->pg_len,
geo_ppaf->lun_offset, geo_ppaf->lun_len,
geo_ppaf->ch_offset, geo_ppaf->ch_len,
geo_ppaf->pln_offset, geo_ppaf->pln_len,
lightnvm: normalize geometry nomenclature Normalize nomenclature for naming channels, luns, chunks, planes and sectors as well as derivations in order to improve readability. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:05:14 +08:00
geo_ppaf->sec_offset, geo_ppaf->sec_len);
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
return sz;
}
static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page)
{
struct nvm_tgt_dev *dev = pblk->dev;
struct nvm_geo *geo = &dev->geo;
struct pblk_line_meta *lm = &pblk->lm;
struct pblk_line_mgmt *l_mg = &pblk->l_mg;
struct pblk_line *line;
ssize_t sz = 0;
int nr_free_lines;
int cur_data, cur_log;
lightnvm: pblk: sched. metadata on write thread At the moment, line metadata is persisted on a separate work queue, that is kicked each time that a line is closed. The assumption when designing this was that freeing the write thread from creating a new write request was better than the potential impact of writes colliding on the media (user I/O and metadata I/O). Experimentation has proven that this assumption is wrong; collision can cause up to 25% of bandwidth and introduce long tail latencies on the write thread, which potentially cause user write threads to spend more time spinning to get a free entry on the write buffer. This patch moves the metadata logic to the write thread. When a line is closed, remaining metadata is written in memory and is placed on a metadata queue. The write thread then takes the metadata corresponding to the previous line, creates the write request and schedules it to minimize collisions on the media. Using this approach, we see that we can saturate the media's bandwidth, which helps reducing both write latencies and the spinning time for user writer threads. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:17 +08:00
int free_line_cnt = 0, closed_line_cnt = 0, emeta_line_cnt = 0;
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
int d_line_cnt = 0, l_line_cnt = 0;
int gc_full = 0, gc_high = 0, gc_mid = 0, gc_low = 0, gc_empty = 0;
lightnvm: pblk: delete redundant debug line stat Remove a legacy variable that helped verifying the consistency of the run-time metadata for the free line list. With the new metadata layout, this check is no longer necessary. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:18 +08:00
int bad = 0, cor = 0;
lightnvm: pblk: delete redundant buffer pointer After refactoring the metadata path, the backpointer controlling synced I/Os in a line becomes unnecessary; metadata is scheduled on the write thread, thus we know when the end of the line is reached and act on it directly. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:19 +08:00
int msecs = 0, cur_sec = 0, vsc = 0, sec_in_line = 0;
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
int map_weight = 0, meta_weight = 0;
spin_lock(&l_mg->free_lock);
cur_data = (l_mg->data_line) ? l_mg->data_line->id : -1;
cur_log = (l_mg->log_line) ? l_mg->log_line->id : -1;
nr_free_lines = l_mg->nr_free_lines;
list_for_each_entry(line, &l_mg->free_list, list)
free_line_cnt++;
spin_unlock(&l_mg->free_lock);
lightnvm: pblk: sched. metadata on write thread At the moment, line metadata is persisted on a separate work queue, that is kicked each time that a line is closed. The assumption when designing this was that freeing the write thread from creating a new write request was better than the potential impact of writes colliding on the media (user I/O and metadata I/O). Experimentation has proven that this assumption is wrong; collision can cause up to 25% of bandwidth and introduce long tail latencies on the write thread, which potentially cause user write threads to spend more time spinning to get a free entry on the write buffer. This patch moves the metadata logic to the write thread. When a line is closed, remaining metadata is written in memory and is placed on a metadata queue. The write thread then takes the metadata corresponding to the previous line, creates the write request and schedules it to minimize collisions on the media. Using this approach, we see that we can saturate the media's bandwidth, which helps reducing both write latencies and the spinning time for user writer threads. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:17 +08:00
spin_lock(&l_mg->close_lock);
list_for_each_entry(line, &l_mg->emeta_list, list)
emeta_line_cnt++;
spin_unlock(&l_mg->close_lock);
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
spin_lock(&l_mg->gc_lock);
list_for_each_entry(line, &l_mg->gc_full_list, list) {
if (line->type == PBLK_LINETYPE_DATA)
d_line_cnt++;
else if (line->type == PBLK_LINETYPE_LOG)
l_line_cnt++;
closed_line_cnt++;
gc_full++;
}
list_for_each_entry(line, &l_mg->gc_high_list, list) {
if (line->type == PBLK_LINETYPE_DATA)
d_line_cnt++;
else if (line->type == PBLK_LINETYPE_LOG)
l_line_cnt++;
closed_line_cnt++;
gc_high++;
}
list_for_each_entry(line, &l_mg->gc_mid_list, list) {
if (line->type == PBLK_LINETYPE_DATA)
d_line_cnt++;
else if (line->type == PBLK_LINETYPE_LOG)
l_line_cnt++;
closed_line_cnt++;
gc_mid++;
}
list_for_each_entry(line, &l_mg->gc_low_list, list) {
if (line->type == PBLK_LINETYPE_DATA)
d_line_cnt++;
else if (line->type == PBLK_LINETYPE_LOG)
l_line_cnt++;
closed_line_cnt++;
gc_low++;
}
list_for_each_entry(line, &l_mg->gc_empty_list, list) {
if (line->type == PBLK_LINETYPE_DATA)
d_line_cnt++;
else if (line->type == PBLK_LINETYPE_LOG)
l_line_cnt++;
closed_line_cnt++;
gc_empty++;
}
list_for_each_entry(line, &l_mg->bad_list, list)
bad++;
list_for_each_entry(line, &l_mg->corrupt_list, list)
cor++;
spin_unlock(&l_mg->gc_lock);
spin_lock(&l_mg->free_lock);
if (l_mg->data_line) {
cur_sec = l_mg->data_line->cur_sec;
msecs = l_mg->data_line->left_msecs;
lightnvm: pblk: sched. metadata on write thread At the moment, line metadata is persisted on a separate work queue, that is kicked each time that a line is closed. The assumption when designing this was that freeing the write thread from creating a new write request was better than the potential impact of writes colliding on the media (user I/O and metadata I/O). Experimentation has proven that this assumption is wrong; collision can cause up to 25% of bandwidth and introduce long tail latencies on the write thread, which potentially cause user write threads to spend more time spinning to get a free entry on the write buffer. This patch moves the metadata logic to the write thread. When a line is closed, remaining metadata is written in memory and is placed on a metadata queue. The write thread then takes the metadata corresponding to the previous line, creates the write request and schedules it to minimize collisions on the media. Using this approach, we see that we can saturate the media's bandwidth, which helps reducing both write latencies and the spinning time for user writer threads. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:17 +08:00
vsc = le32_to_cpu(*l_mg->data_line->vsc);
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
sec_in_line = l_mg->data_line->sec_in_line;
meta_weight = bitmap_weight(&l_mg->meta_bitmap,
PBLK_DATA_LINES);
map_weight = bitmap_weight(l_mg->data_line->map_bitmap,
lm->sec_per_line);
}
spin_unlock(&l_mg->free_lock);
if (nr_free_lines != free_line_cnt)
lightnvm: pblk: redesign GC algorithm At the moment, in order to get enough read parallelism, we have recycled several lines at the same time. This approach has proven not to work well when reaching capacity, since we end up mixing valid data from all lines, thus not maintaining a sustainable free/recycled line ratio. The new design, relies on a two level workqueue mechanism. In the first level, we read the metadata for a number of lines based on the GC list they reside on (this is governed by the number of valid sectors in each line). In the second level, we recycle a single line at a time. Here, we issue reads in parallel, while a single GC write thread places data in the write buffer. This design allows to (i) only move data from one line at a time, thus maintaining a sane free/recycled ration and (ii) maintain the GC writer busy with recycled data. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:27 +08:00
pr_err("pblk: corrupted free line list:%d/%d\n",
nr_free_lines, free_line_cnt);
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
sz = snprintf(page, PAGE_SIZE - sz,
"line: nluns:%d, nblks:%d, nsecs:%d\n",
lightnvm: make geometry structures 2.0 ready Prepare for the 2.0 revision by adapting the geometry structures to coexist with the 1.2 revision. Signed-off-by: Matias Bjørling <m@bjorling.me> Reviewed-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-05 21:16:03 +08:00
geo->all_luns, lm->blk_per_line, lm->sec_per_line);
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
sz += snprintf(page + sz, PAGE_SIZE - sz,
lightnvm: pblk: fail gracefully on irrec. error Due to user writes being decoupled from media writes because of the need of an intermediate write buffer, irrecoverable media write errors lead to pblk stalling; user writes fill up the buffer and end up in an infinite retry loop. In order to let user writes fail gracefully, it is necessary for pblk to keep track of its own internal state and prevent further writes from being placed into the write buffer. This patch implements a state machine to keep track of internal errors and, in case of failure, fail further user writes in an standard way. Depending on the type of error, pblk will do its best to persist buffered writes (which are already acknowledged) and close down on a graceful manner. This way, data might be recovered by re-instantiating pblk. Such state machine paves out the way for a state-based FTL log. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:29 +08:00
"lines:d:%d,l:%d-f:%d,m:%d/%d,c:%d,b:%d,co:%d(d:%d,l:%d)t:%d\n",
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
cur_data, cur_log,
lightnvm: pblk: fail gracefully on irrec. error Due to user writes being decoupled from media writes because of the need of an intermediate write buffer, irrecoverable media write errors lead to pblk stalling; user writes fill up the buffer and end up in an infinite retry loop. In order to let user writes fail gracefully, it is necessary for pblk to keep track of its own internal state and prevent further writes from being placed into the write buffer. This patch implements a state machine to keep track of internal errors and, in case of failure, fail further user writes in an standard way. Depending on the type of error, pblk will do its best to persist buffered writes (which are already acknowledged) and close down on a graceful manner. This way, data might be recovered by re-instantiating pblk. Such state machine paves out the way for a state-based FTL log. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:29 +08:00
nr_free_lines,
emeta_line_cnt, meta_weight,
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
closed_line_cnt,
lightnvm: pblk: sched. metadata on write thread At the moment, line metadata is persisted on a separate work queue, that is kicked each time that a line is closed. The assumption when designing this was that freeing the write thread from creating a new write request was better than the potential impact of writes colliding on the media (user I/O and metadata I/O). Experimentation has proven that this assumption is wrong; collision can cause up to 25% of bandwidth and introduce long tail latencies on the write thread, which potentially cause user write threads to spend more time spinning to get a free entry on the write buffer. This patch moves the metadata logic to the write thread. When a line is closed, remaining metadata is written in memory and is placed on a metadata queue. The write thread then takes the metadata corresponding to the previous line, creates the write request and schedules it to minimize collisions on the media. Using this approach, we see that we can saturate the media's bandwidth, which helps reducing both write latencies and the spinning time for user writer threads. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:17 +08:00
bad, cor,
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
d_line_cnt, l_line_cnt,
l_mg->nr_lines);
sz += snprintf(page + sz, PAGE_SIZE - sz,
"GC: full:%d, high:%d, mid:%d, low:%d, empty:%d, queue:%d\n",
gc_full, gc_high, gc_mid, gc_low, gc_empty,
lightnvm: pblk: gc all lines in the pipeline before exit Finish garbage collect of the lines that are in the gc pipeline before exiting. Ensure that all lines already in in the pipeline goes through, from read to write. Do this by keeping track of how many lines are in the pipeline and waiting for that number to reach zero before exiting the gc reader task. Since we're adding a new gc line counter, change the name of inflight_gc to read_inflight_gc to make the distinction clear. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-13 20:46:41 +08:00
atomic_read(&pblk->gc.read_inflight_gc));
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
sz += snprintf(page + sz, PAGE_SIZE - sz,
lightnvm: pblk: delete redundant buffer pointer After refactoring the metadata path, the backpointer controlling synced I/Os in a line becomes unnecessary; metadata is scheduled on the write thread, thus we know when the end of the line is reached and act on it directly. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:19 +08:00
"data (%d) cur:%d, left:%d, vsc:%d, s:%d, map:%d/%d (%d)\n",
cur_data, cur_sec, msecs, vsc, sec_in_line,
lightnvm: pblk: fail gracefully on irrec. error Due to user writes being decoupled from media writes because of the need of an intermediate write buffer, irrecoverable media write errors lead to pblk stalling; user writes fill up the buffer and end up in an infinite retry loop. In order to let user writes fail gracefully, it is necessary for pblk to keep track of its own internal state and prevent further writes from being placed into the write buffer. This patch implements a state machine to keep track of internal errors and, in case of failure, fail further user writes in an standard way. Depending on the type of error, pblk will do its best to persist buffered writes (which are already acknowledged) and close down on a graceful manner. This way, data might be recovered by re-instantiating pblk. Such state machine paves out the way for a state-based FTL log. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:29 +08:00
map_weight, lm->sec_per_line,
atomic_read(&pblk->inflight_io));
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
return sz;
}
static ssize_t pblk_sysfs_lines_info(struct pblk *pblk, char *page)
{
struct nvm_tgt_dev *dev = pblk->dev;
struct nvm_geo *geo = &dev->geo;
struct pblk_line_meta *lm = &pblk->lm;
ssize_t sz = 0;
sz = snprintf(page, PAGE_SIZE - sz,
"smeta - len:%d, secs:%d\n",
lm->smeta_len, lm->smeta_sec);
sz += snprintf(page + sz, PAGE_SIZE - sz,
"emeta - len:%d, sec:%d, bb_start:%d\n",
lightnvm: pblk: sched. metadata on write thread At the moment, line metadata is persisted on a separate work queue, that is kicked each time that a line is closed. The assumption when designing this was that freeing the write thread from creating a new write request was better than the potential impact of writes colliding on the media (user I/O and metadata I/O). Experimentation has proven that this assumption is wrong; collision can cause up to 25% of bandwidth and introduce long tail latencies on the write thread, which potentially cause user write threads to spend more time spinning to get a free entry on the write buffer. This patch moves the metadata logic to the write thread. When a line is closed, remaining metadata is written in memory and is placed on a metadata queue. The write thread then takes the metadata corresponding to the previous line, creates the write request and schedules it to minimize collisions on the media. Using this approach, we see that we can saturate the media's bandwidth, which helps reducing both write latencies and the spinning time for user writer threads. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:17 +08:00
lm->emeta_len[0], lm->emeta_sec[0],
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
lm->emeta_bb);
sz += snprintf(page + sz, PAGE_SIZE - sz,
"bitmap lengths: sec:%d, blk:%d, lun:%d\n",
lm->sec_bitmap_len,
lm->blk_bitmap_len,
lm->lun_bitmap_len);
sz += snprintf(page + sz, PAGE_SIZE - sz,
"blk_line:%d, sec_line:%d, sec_blk:%d\n",
lm->blk_per_line,
lm->sec_per_line,
lightnvm: simplify geometry structure Currently, the device geometry is stored redundantly in the nvm_id and nvm_geo structures at a device level. Moreover, when instantiating targets on a specific number of LUNs, these structures are replicated and manually modified to fit the instance channel and LUN partitioning. Instead, create a generic geometry around nvm_geo, which can be used by (i) the underlying device to describe the geometry of the whole device, and (ii) instances to describe their geometry independently. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:05:10 +08:00
geo->clba);
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
return sz;
}
lightnvm: pblk: expose max sec per write on sysfs Allow to configure the number of maximum sectors per write command through sysfs. This makes it easier to tune write command sizes for different controller configurations. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:14 +08:00
static ssize_t pblk_sysfs_get_sec_per_write(struct pblk *pblk, char *page)
{
return snprintf(page, PAGE_SIZE, "%d\n", pblk->sec_per_write);
}
lightnvm: pblk: export write amplification counters to sysfs In a SSD, write amplification, WA, is defined as the average number of page writes per user page write. Write amplification negatively affects write performance and decreases the lifetime of the disk, so it's a useful metric to add to sysfs. In plkb's case, the number of writes per user sector is the sum of: (1) number of user writes (2) number of sectors written by the garbage collector (3) number of sectors padded (i.e. due to syncs) This patch adds persistent counters for 1-3 and two sysfs attributes to export these along with WA calculated with five decimals: write_amp_mileage: the accumulated write amplification stats for the lifetime of the pblk instance write_amp_trip: resetable stats to facilitate delta measurements, values reset at creation and if 0 is written to the attribute. 64-bit counters are used as a 32 bit counter would wrap around already after about 17 TB worth of user data. It will take a long long time before the 64 bit sector counters wrap around. The counters are stored after the bad block bitmap in the first emeta sector of each written line. There is plenty of space in the first emeta sector, so we don't need to bump the major version of the line data format. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:52 +08:00
static ssize_t pblk_get_write_amp(u64 user, u64 gc, u64 pad,
char *page)
{
int sz;
sz = snprintf(page, PAGE_SIZE,
"user:%lld gc:%lld pad:%lld WA:",
user, gc, pad);
if (!user) {
sz += snprintf(page + sz, PAGE_SIZE - sz, "NaN\n");
} else {
u64 wa_int;
u32 wa_frac;
wa_int = (user + gc + pad) * 100000;
wa_int = div_u64(wa_int, user);
wa_int = div_u64_rem(wa_int, 100000, &wa_frac);
sz += snprintf(page + sz, PAGE_SIZE - sz, "%llu.%05u\n",
wa_int, wa_frac);
}
return sz;
}
static ssize_t pblk_sysfs_get_write_amp_mileage(struct pblk *pblk, char *page)
{
return pblk_get_write_amp(atomic64_read(&pblk->user_wa),
atomic64_read(&pblk->gc_wa), atomic64_read(&pblk->pad_wa),
page);
}
static ssize_t pblk_sysfs_get_write_amp_trip(struct pblk *pblk, char *page)
{
return pblk_get_write_amp(
atomic64_read(&pblk->user_wa) - pblk->user_rst_wa,
atomic64_read(&pblk->gc_wa) - pblk->gc_rst_wa,
atomic64_read(&pblk->pad_wa) - pblk->pad_rst_wa, page);
}
lightnvm: pblk: add padding distribution sysfs attribute When pblk receives a sync, all data up to that point in the write buffer must be comitted to persistent storage, and as flash memory comes with a minimal write size there is a significant cost involved both in terms of time for completing the sync and in terms of write amplification padded sectors for filling up to the minimal write size. In order to get a better understanding of the costs involved for syncs, Add a sysfs attribute to pblk: padded_dist, showing a normalized distribution of sectors padded. In order to facilitate measurements of specific workloads during the lifetime of the pblk instance, the distribution can be reset by writing 0 to the attribute. Do this by introducing counters for each possible padding: {0..(minimal write size - 1)} and calculate the normalized distribution when showing the attribute. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Rearranged total_buckets statement in pblk_sysfs_get_padding_dist Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:55 +08:00
static long long bucket_percentage(unsigned long long bucket,
unsigned long long total)
{
int p = bucket * 100;
p = div_u64(p, total);
return p;
}
static ssize_t pblk_sysfs_get_padding_dist(struct pblk *pblk, char *page)
{
int sz = 0;
unsigned long long total;
unsigned long long total_buckets = 0;
int buckets = pblk->min_write_pgs - 1;
int i;
total = atomic64_read(&pblk->nr_flush) - pblk->nr_flush_rst;
if (!total) {
for (i = 0; i < (buckets + 1); i++)
sz += snprintf(page + sz, PAGE_SIZE - sz,
"%d:0 ", i);
sz += snprintf(page + sz, PAGE_SIZE - sz, "\n");
return sz;
}
for (i = 0; i < buckets; i++)
total_buckets += atomic64_read(&pblk->pad_dist[i]);
sz += snprintf(page + sz, PAGE_SIZE - sz, "0:%lld%% ",
bucket_percentage(total - total_buckets, total));
for (i = 0; i < buckets; i++) {
unsigned long long p;
p = bucket_percentage(atomic64_read(&pblk->pad_dist[i]),
total);
sz += snprintf(page + sz, PAGE_SIZE - sz, "%d:%lld%% ",
i + 1, p);
}
sz += snprintf(page + sz, PAGE_SIZE - sz, "\n");
return sz;
}
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
#ifdef CONFIG_NVM_DEBUG
static ssize_t pblk_sysfs_stats_debug(struct pblk *pblk, char *page)
{
return snprintf(page, PAGE_SIZE,
lightnvm: pblk: add padding distribution sysfs attribute When pblk receives a sync, all data up to that point in the write buffer must be comitted to persistent storage, and as flash memory comes with a minimal write size there is a significant cost involved both in terms of time for completing the sync and in terms of write amplification padded sectors for filling up to the minimal write size. In order to get a better understanding of the costs involved for syncs, Add a sysfs attribute to pblk: padded_dist, showing a normalized distribution of sectors padded. In order to facilitate measurements of specific workloads during the lifetime of the pblk instance, the distribution can be reset by writing 0 to the attribute. Do this by introducing counters for each possible padding: {0..(minimal write size - 1)} and calculate the normalized distribution when showing the attribute. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Rearranged total_buckets statement in pblk_sysfs_get_padding_dist Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:55 +08:00
"%lu\t%lu\t%ld\t%llu\t%ld\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\n",
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
atomic_long_read(&pblk->inflight_writes),
atomic_long_read(&pblk->inflight_reads),
atomic_long_read(&pblk->req_writes),
lightnvm: pblk: add padding distribution sysfs attribute When pblk receives a sync, all data up to that point in the write buffer must be comitted to persistent storage, and as flash memory comes with a minimal write size there is a significant cost involved both in terms of time for completing the sync and in terms of write amplification padded sectors for filling up to the minimal write size. In order to get a better understanding of the costs involved for syncs, Add a sysfs attribute to pblk: padded_dist, showing a normalized distribution of sectors padded. In order to facilitate measurements of specific workloads during the lifetime of the pblk instance, the distribution can be reset by writing 0 to the attribute. Do this by introducing counters for each possible padding: {0..(minimal write size - 1)} and calculate the normalized distribution when showing the attribute. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Rearranged total_buckets statement in pblk_sysfs_get_padding_dist Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:55 +08:00
(u64)atomic64_read(&pblk->nr_flush),
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
atomic_long_read(&pblk->padded_writes),
atomic_long_read(&pblk->padded_wb),
atomic_long_read(&pblk->sub_writes),
atomic_long_read(&pblk->sync_writes),
atomic_long_read(&pblk->recov_writes),
atomic_long_read(&pblk->recov_gc_writes),
atomic_long_read(&pblk->recov_gc_reads),
lightnvm: pblk: add debug stat for read cache hits Add a new debug counter to measure cache hits on the read path Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:13 +08:00
atomic_long_read(&pblk->cache_reads),
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
atomic_long_read(&pblk->sync_reads));
}
#endif
static ssize_t pblk_sysfs_gc_force(struct pblk *pblk, const char *page,
size_t len)
{
size_t c_len;
lightnvm: pblk: remove unused return variable Remove unused variable. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-30 23:56:36 +08:00
int force;
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
c_len = strcspn(page, "\n");
if (c_len >= len)
return -EINVAL;
if (kstrtouint(page, 0, &force))
return -EINVAL;
lightnvm: pblk: remove unused return variable Remove unused variable. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-30 23:56:36 +08:00
pblk_gc_sysfs_force(pblk, force);
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
return len;
}
lightnvm: pblk: expose max sec per write on sysfs Allow to configure the number of maximum sectors per write command through sysfs. This makes it easier to tune write command sizes for different controller configurations. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:14 +08:00
static ssize_t pblk_sysfs_set_sec_per_write(struct pblk *pblk,
const char *page, size_t len)
{
size_t c_len;
int sec_per_write;
c_len = strcspn(page, "\n");
if (c_len >= len)
return -EINVAL;
if (kstrtouint(page, 0, &sec_per_write))
return -EINVAL;
if (sec_per_write < pblk->min_write_pgs
|| sec_per_write > pblk->max_write_pgs
|| sec_per_write % pblk->min_write_pgs != 0)
return -EINVAL;
pblk_set_sec_per_write(pblk, sec_per_write);
return len;
}
lightnvm: pblk: export write amplification counters to sysfs In a SSD, write amplification, WA, is defined as the average number of page writes per user page write. Write amplification negatively affects write performance and decreases the lifetime of the disk, so it's a useful metric to add to sysfs. In plkb's case, the number of writes per user sector is the sum of: (1) number of user writes (2) number of sectors written by the garbage collector (3) number of sectors padded (i.e. due to syncs) This patch adds persistent counters for 1-3 and two sysfs attributes to export these along with WA calculated with five decimals: write_amp_mileage: the accumulated write amplification stats for the lifetime of the pblk instance write_amp_trip: resetable stats to facilitate delta measurements, values reset at creation and if 0 is written to the attribute. 64-bit counters are used as a 32 bit counter would wrap around already after about 17 TB worth of user data. It will take a long long time before the 64 bit sector counters wrap around. The counters are stored after the bad block bitmap in the first emeta sector of each written line. There is plenty of space in the first emeta sector, so we don't need to bump the major version of the line data format. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:52 +08:00
static ssize_t pblk_sysfs_set_write_amp_trip(struct pblk *pblk,
const char *page, size_t len)
{
size_t c_len;
int reset_value;
c_len = strcspn(page, "\n");
if (c_len >= len)
return -EINVAL;
if (kstrtouint(page, 0, &reset_value))
return -EINVAL;
if (reset_value != 0)
return -EINVAL;
pblk->user_rst_wa = atomic64_read(&pblk->user_wa);
pblk->pad_rst_wa = atomic64_read(&pblk->pad_wa);
pblk->gc_rst_wa = atomic64_read(&pblk->gc_wa);
return len;
}
lightnvm: pblk: add padding distribution sysfs attribute When pblk receives a sync, all data up to that point in the write buffer must be comitted to persistent storage, and as flash memory comes with a minimal write size there is a significant cost involved both in terms of time for completing the sync and in terms of write amplification padded sectors for filling up to the minimal write size. In order to get a better understanding of the costs involved for syncs, Add a sysfs attribute to pblk: padded_dist, showing a normalized distribution of sectors padded. In order to facilitate measurements of specific workloads during the lifetime of the pblk instance, the distribution can be reset by writing 0 to the attribute. Do this by introducing counters for each possible padding: {0..(minimal write size - 1)} and calculate the normalized distribution when showing the attribute. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Rearranged total_buckets statement in pblk_sysfs_get_padding_dist Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:55 +08:00
static ssize_t pblk_sysfs_set_padding_dist(struct pblk *pblk,
const char *page, size_t len)
{
size_t c_len;
int reset_value;
int buckets = pblk->min_write_pgs - 1;
int i;
c_len = strcspn(page, "\n");
if (c_len >= len)
return -EINVAL;
if (kstrtouint(page, 0, &reset_value))
return -EINVAL;
if (reset_value != 0)
return -EINVAL;
for (i = 0; i < buckets; i++)
atomic64_set(&pblk->pad_dist[i], 0);
pblk->nr_flush_rst = atomic64_read(&pblk->nr_flush);
return len;
}
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
static struct attribute sys_write_luns = {
.name = "write_luns",
.mode = 0444,
};
static struct attribute sys_rate_limiter_attr = {
.name = "rate_limiter",
.mode = 0444,
};
static struct attribute sys_gc_state = {
.name = "gc_state",
.mode = 0444,
};
static struct attribute sys_errors_attr = {
.name = "errors",
.mode = 0444,
};
static struct attribute sys_rb_attr = {
.name = "write_buffer",
.mode = 0444,
};
static struct attribute sys_stats_ppaf_attr = {
.name = "ppa_format",
.mode = 0444,
};
static struct attribute sys_lines_attr = {
.name = "lines",
.mode = 0444,
};
static struct attribute sys_lines_info_attr = {
.name = "lines_info",
.mode = 0444,
};
static struct attribute sys_gc_force = {
.name = "gc_force",
.mode = 0200,
};
lightnvm: pblk: expose max sec per write on sysfs Allow to configure the number of maximum sectors per write command through sysfs. This makes it easier to tune write command sizes for different controller configurations. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:14 +08:00
static struct attribute sys_max_sec_per_write = {
.name = "max_sec_per_write",
.mode = 0644,
};
lightnvm: pblk: export write amplification counters to sysfs In a SSD, write amplification, WA, is defined as the average number of page writes per user page write. Write amplification negatively affects write performance and decreases the lifetime of the disk, so it's a useful metric to add to sysfs. In plkb's case, the number of writes per user sector is the sum of: (1) number of user writes (2) number of sectors written by the garbage collector (3) number of sectors padded (i.e. due to syncs) This patch adds persistent counters for 1-3 and two sysfs attributes to export these along with WA calculated with five decimals: write_amp_mileage: the accumulated write amplification stats for the lifetime of the pblk instance write_amp_trip: resetable stats to facilitate delta measurements, values reset at creation and if 0 is written to the attribute. 64-bit counters are used as a 32 bit counter would wrap around already after about 17 TB worth of user data. It will take a long long time before the 64 bit sector counters wrap around. The counters are stored after the bad block bitmap in the first emeta sector of each written line. There is plenty of space in the first emeta sector, so we don't need to bump the major version of the line data format. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:52 +08:00
static struct attribute sys_write_amp_mileage = {
.name = "write_amp_mileage",
.mode = 0444,
};
static struct attribute sys_write_amp_trip = {
.name = "write_amp_trip",
.mode = 0644,
};
lightnvm: pblk: add padding distribution sysfs attribute When pblk receives a sync, all data up to that point in the write buffer must be comitted to persistent storage, and as flash memory comes with a minimal write size there is a significant cost involved both in terms of time for completing the sync and in terms of write amplification padded sectors for filling up to the minimal write size. In order to get a better understanding of the costs involved for syncs, Add a sysfs attribute to pblk: padded_dist, showing a normalized distribution of sectors padded. In order to facilitate measurements of specific workloads during the lifetime of the pblk instance, the distribution can be reset by writing 0 to the attribute. Do this by introducing counters for each possible padding: {0..(minimal write size - 1)} and calculate the normalized distribution when showing the attribute. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Rearranged total_buckets statement in pblk_sysfs_get_padding_dist Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:55 +08:00
static struct attribute sys_padding_dist = {
.name = "padding_dist",
.mode = 0644,
};
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
#ifdef CONFIG_NVM_DEBUG
static struct attribute sys_stats_debug_attr = {
.name = "stats",
.mode = 0444,
};
#endif
static struct attribute *pblk_attrs[] = {
&sys_write_luns,
&sys_rate_limiter_attr,
&sys_errors_attr,
&sys_gc_state,
&sys_gc_force,
lightnvm: pblk: expose max sec per write on sysfs Allow to configure the number of maximum sectors per write command through sysfs. This makes it easier to tune write command sizes for different controller configurations. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:14 +08:00
&sys_max_sec_per_write,
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
&sys_rb_attr,
&sys_stats_ppaf_attr,
&sys_lines_attr,
&sys_lines_info_attr,
lightnvm: pblk: export write amplification counters to sysfs In a SSD, write amplification, WA, is defined as the average number of page writes per user page write. Write amplification negatively affects write performance and decreases the lifetime of the disk, so it's a useful metric to add to sysfs. In plkb's case, the number of writes per user sector is the sum of: (1) number of user writes (2) number of sectors written by the garbage collector (3) number of sectors padded (i.e. due to syncs) This patch adds persistent counters for 1-3 and two sysfs attributes to export these along with WA calculated with five decimals: write_amp_mileage: the accumulated write amplification stats for the lifetime of the pblk instance write_amp_trip: resetable stats to facilitate delta measurements, values reset at creation and if 0 is written to the attribute. 64-bit counters are used as a 32 bit counter would wrap around already after about 17 TB worth of user data. It will take a long long time before the 64 bit sector counters wrap around. The counters are stored after the bad block bitmap in the first emeta sector of each written line. There is plenty of space in the first emeta sector, so we don't need to bump the major version of the line data format. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:52 +08:00
&sys_write_amp_mileage,
&sys_write_amp_trip,
lightnvm: pblk: add padding distribution sysfs attribute When pblk receives a sync, all data up to that point in the write buffer must be comitted to persistent storage, and as flash memory comes with a minimal write size there is a significant cost involved both in terms of time for completing the sync and in terms of write amplification padded sectors for filling up to the minimal write size. In order to get a better understanding of the costs involved for syncs, Add a sysfs attribute to pblk: padded_dist, showing a normalized distribution of sectors padded. In order to facilitate measurements of specific workloads during the lifetime of the pblk instance, the distribution can be reset by writing 0 to the attribute. Do this by introducing counters for each possible padding: {0..(minimal write size - 1)} and calculate the normalized distribution when showing the attribute. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Rearranged total_buckets statement in pblk_sysfs_get_padding_dist Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:55 +08:00
&sys_padding_dist,
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
#ifdef CONFIG_NVM_DEBUG
&sys_stats_debug_attr,
#endif
NULL,
};
static ssize_t pblk_sysfs_show(struct kobject *kobj, struct attribute *attr,
char *buf)
{
struct pblk *pblk = container_of(kobj, struct pblk, kobj);
if (strcmp(attr->name, "rate_limiter") == 0)
return pblk_sysfs_rate_limiter(pblk, buf);
else if (strcmp(attr->name, "write_luns") == 0)
return pblk_sysfs_luns_show(pblk, buf);
else if (strcmp(attr->name, "gc_state") == 0)
return pblk_sysfs_gc_state_show(pblk, buf);
else if (strcmp(attr->name, "errors") == 0)
return pblk_sysfs_stats(pblk, buf);
else if (strcmp(attr->name, "write_buffer") == 0)
return pblk_sysfs_write_buffer(pblk, buf);
else if (strcmp(attr->name, "ppa_format") == 0)
return pblk_sysfs_ppaf(pblk, buf);
else if (strcmp(attr->name, "lines") == 0)
return pblk_sysfs_lines(pblk, buf);
else if (strcmp(attr->name, "lines_info") == 0)
return pblk_sysfs_lines_info(pblk, buf);
lightnvm: pblk: expose max sec per write on sysfs Allow to configure the number of maximum sectors per write command through sysfs. This makes it easier to tune write command sizes for different controller configurations. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:14 +08:00
else if (strcmp(attr->name, "max_sec_per_write") == 0)
return pblk_sysfs_get_sec_per_write(pblk, buf);
lightnvm: pblk: export write amplification counters to sysfs In a SSD, write amplification, WA, is defined as the average number of page writes per user page write. Write amplification negatively affects write performance and decreases the lifetime of the disk, so it's a useful metric to add to sysfs. In plkb's case, the number of writes per user sector is the sum of: (1) number of user writes (2) number of sectors written by the garbage collector (3) number of sectors padded (i.e. due to syncs) This patch adds persistent counters for 1-3 and two sysfs attributes to export these along with WA calculated with five decimals: write_amp_mileage: the accumulated write amplification stats for the lifetime of the pblk instance write_amp_trip: resetable stats to facilitate delta measurements, values reset at creation and if 0 is written to the attribute. 64-bit counters are used as a 32 bit counter would wrap around already after about 17 TB worth of user data. It will take a long long time before the 64 bit sector counters wrap around. The counters are stored after the bad block bitmap in the first emeta sector of each written line. There is plenty of space in the first emeta sector, so we don't need to bump the major version of the line data format. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:52 +08:00
else if (strcmp(attr->name, "write_amp_mileage") == 0)
return pblk_sysfs_get_write_amp_mileage(pblk, buf);
else if (strcmp(attr->name, "write_amp_trip") == 0)
return pblk_sysfs_get_write_amp_trip(pblk, buf);
lightnvm: pblk: add padding distribution sysfs attribute When pblk receives a sync, all data up to that point in the write buffer must be comitted to persistent storage, and as flash memory comes with a minimal write size there is a significant cost involved both in terms of time for completing the sync and in terms of write amplification padded sectors for filling up to the minimal write size. In order to get a better understanding of the costs involved for syncs, Add a sysfs attribute to pblk: padded_dist, showing a normalized distribution of sectors padded. In order to facilitate measurements of specific workloads during the lifetime of the pblk instance, the distribution can be reset by writing 0 to the attribute. Do this by introducing counters for each possible padding: {0..(minimal write size - 1)} and calculate the normalized distribution when showing the attribute. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Rearranged total_buckets statement in pblk_sysfs_get_padding_dist Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:55 +08:00
else if (strcmp(attr->name, "padding_dist") == 0)
return pblk_sysfs_get_padding_dist(pblk, buf);
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
#ifdef CONFIG_NVM_DEBUG
else if (strcmp(attr->name, "stats") == 0)
return pblk_sysfs_stats_debug(pblk, buf);
#endif
return 0;
}
static ssize_t pblk_sysfs_store(struct kobject *kobj, struct attribute *attr,
const char *buf, size_t len)
{
struct pblk *pblk = container_of(kobj, struct pblk, kobj);
lightnvm: pblk: redesign GC algorithm At the moment, in order to get enough read parallelism, we have recycled several lines at the same time. This approach has proven not to work well when reaching capacity, since we end up mixing valid data from all lines, thus not maintaining a sustainable free/recycled line ratio. The new design, relies on a two level workqueue mechanism. In the first level, we read the metadata for a number of lines based on the GC list they reside on (this is governed by the number of valid sectors in each line). In the second level, we recycle a single line at a time. Here, we issue reads in parallel, while a single GC write thread places data in the write buffer. This design allows to (i) only move data from one line at a time, thus maintaining a sane free/recycled ration and (ii) maintain the GC writer busy with recycled data. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:27 +08:00
if (strcmp(attr->name, "gc_force") == 0)
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
return pblk_sysfs_gc_force(pblk, buf, len);
lightnvm: pblk: expose max sec per write on sysfs Allow to configure the number of maximum sectors per write command through sysfs. This makes it easier to tune write command sizes for different controller configurations. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26 17:57:14 +08:00
else if (strcmp(attr->name, "max_sec_per_write") == 0)
return pblk_sysfs_set_sec_per_write(pblk, buf, len);
lightnvm: pblk: export write amplification counters to sysfs In a SSD, write amplification, WA, is defined as the average number of page writes per user page write. Write amplification negatively affects write performance and decreases the lifetime of the disk, so it's a useful metric to add to sysfs. In plkb's case, the number of writes per user sector is the sum of: (1) number of user writes (2) number of sectors written by the garbage collector (3) number of sectors padded (i.e. due to syncs) This patch adds persistent counters for 1-3 and two sysfs attributes to export these along with WA calculated with five decimals: write_amp_mileage: the accumulated write amplification stats for the lifetime of the pblk instance write_amp_trip: resetable stats to facilitate delta measurements, values reset at creation and if 0 is written to the attribute. 64-bit counters are used as a 32 bit counter would wrap around already after about 17 TB worth of user data. It will take a long long time before the 64 bit sector counters wrap around. The counters are stored after the bad block bitmap in the first emeta sector of each written line. There is plenty of space in the first emeta sector, so we don't need to bump the major version of the line data format. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:52 +08:00
else if (strcmp(attr->name, "write_amp_trip") == 0)
return pblk_sysfs_set_write_amp_trip(pblk, buf, len);
lightnvm: pblk: add padding distribution sysfs attribute When pblk receives a sync, all data up to that point in the write buffer must be comitted to persistent storage, and as flash memory comes with a minimal write size there is a significant cost involved both in terms of time for completing the sync and in terms of write amplification padded sectors for filling up to the minimal write size. In order to get a better understanding of the costs involved for syncs, Add a sysfs attribute to pblk: padded_dist, showing a normalized distribution of sectors padded. In order to facilitate measurements of specific workloads during the lifetime of the pblk instance, the distribution can be reset by writing 0 to the attribute. Do this by introducing counters for each possible padding: {0..(minimal write size - 1)} and calculate the normalized distribution when showing the attribute. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Rearranged total_buckets statement in pblk_sysfs_get_padding_dist Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-30 06:04:55 +08:00
else if (strcmp(attr->name, "padding_dist") == 0)
return pblk_sysfs_set_padding_dist(pblk, buf, len);
lightnvm: physical block device (pblk) target This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16 02:55:50 +08:00
return 0;
}
static const struct sysfs_ops pblk_sysfs_ops = {
.show = pblk_sysfs_show,
.store = pblk_sysfs_store,
};
static struct kobj_type pblk_ktype = {
.sysfs_ops = &pblk_sysfs_ops,
.default_attrs = pblk_attrs,
};
int pblk_sysfs_init(struct gendisk *tdisk)
{
struct pblk *pblk = tdisk->private_data;
struct device *parent_dev = disk_to_dev(pblk->disk);
int ret;
ret = kobject_init_and_add(&pblk->kobj, &pblk_ktype,
kobject_get(&parent_dev->kobj),
"%s", "pblk");
if (ret) {
pr_err("pblk: could not register %s/pblk\n",
tdisk->disk_name);
return ret;
}
kobject_uevent(&pblk->kobj, KOBJ_ADD);
return 0;
}
void pblk_sysfs_exit(struct gendisk *tdisk)
{
struct pblk *pblk = tdisk->private_data;
kobject_uevent(&pblk->kobj, KOBJ_REMOVE);
kobject_del(&pblk->kobj);
kobject_put(&pblk->kobj);
}
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