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bcache: Use blkdev_issue_discard()

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The old asynchronous discard code was really a relic from when all the
allocation code was asynchronous - now that allocation runs out of a
dedicated thread there's no point in keeping around all that complicated
machinery.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
This commit is contained in:
Kent Overstreet 2013-07-24 17:16:09 -07:00
parent dd9ec84da5
commit 49b1212dfa
3 changed files with 11 additions and 117 deletions
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114
drivers/md/bcache/alloc.c
View File

@ -63,13 +63,12 @@
#include "bcache.h"
#include "btree.h"
#include <linux/blkdev.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/random.h>
#include <trace/events/bcache.h>
#define MAX_IN_FLIGHT_DISCARDS 8U
/* Bucket heap / gen */
uint8_t bch_inc_gen(struct cache *ca, struct bucket *b)
@ -121,75 +120,6 @@ void bch_rescale_priorities(struct cache_set *c, int sectors)
mutex_unlock(&c->bucket_lock);
}
/* Discard/TRIM */
struct discard {
struct list_head list;
struct work_struct work;
struct cache *ca;
long bucket;
struct bio bio;
struct bio_vec bv;
};
static void discard_finish(struct work_struct *w)
{
struct discard *d = container_of(w, struct discard, work);
struct cache *ca = d->ca;
char buf[BDEVNAME_SIZE];
if (!test_bit(BIO_UPTODATE, &d->bio.bi_flags)) {
pr_notice("discard error on %s, disabling",
bdevname(ca->bdev, buf));
d->ca->discard = 0;
}
mutex_lock(&ca->set->bucket_lock);
fifo_push(&ca->free, d->bucket);
list_add(&d->list, &ca->discards);
atomic_dec(&ca->discards_in_flight);
mutex_unlock(&ca->set->bucket_lock);
closure_wake_up(&ca->set->bucket_wait);
wake_up_process(ca->alloc_thread);
closure_put(&ca->set->cl);
}
static void discard_endio(struct bio *bio, int error)
{
struct discard *d = container_of(bio, struct discard, bio);
schedule_work(&d->work);
}
static void do_discard(struct cache *ca, long bucket)
{
struct discard *d = list_first_entry(&ca->discards,
struct discard, list);
list_del(&d->list);
d->bucket = bucket;
atomic_inc(&ca->discards_in_flight);
closure_get(&ca->set->cl);
bio_init(&d->bio);
d->bio.bi_sector = bucket_to_sector(ca->set, d->bucket);
d->bio.bi_bdev = ca->bdev;
d->bio.bi_rw = REQ_WRITE|REQ_DISCARD;
d->bio.bi_max_vecs = 1;
d->bio.bi_io_vec = d->bio.bi_inline_vecs;
d->bio.bi_size = bucket_bytes(ca);
d->bio.bi_end_io = discard_endio;
bio_set_prio(&d->bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
submit_bio(0, &d->bio);
}
/* Allocation */
static inline bool can_inc_bucket_gen(struct bucket *b)
@ -398,16 +328,18 @@ static int bch_allocator_thread(void *arg)
else
break;
allocator_wait(ca, (int) fifo_free(&ca->free) >
atomic_read(&ca->discards_in_flight));
if (ca->discard) {
allocator_wait(ca, !list_empty(&ca->discards));
do_discard(ca, bucket);
} else {
fifo_push(&ca->free, bucket);
closure_wake_up(&ca->set->bucket_wait);
mutex_unlock(&ca->set->bucket_lock);
blkdev_issue_discard(ca->bdev,
bucket_to_sector(ca->set, bucket),
ca->sb.block_size, GFP_KERNEL, 0);
mutex_lock(&ca->set->bucket_lock);
}
allocator_wait(ca, !fifo_full(&ca->free));
fifo_push(&ca->free, bucket);
closure_wake_up(&ca->set->bucket_wait);
}
/*
@ -556,22 +488,8 @@ int bch_cache_allocator_start(struct cache *ca)
return 0;
}
void bch_cache_allocator_exit(struct cache *ca)
{
struct discard *d;
while (!list_empty(&ca->discards)) {
d = list_first_entry(&ca->discards, struct discard, list);
cancel_work_sync(&d->work);
list_del(&d->list);
kfree(d);
}
}
int bch_cache_allocator_init(struct cache *ca)
{
unsigned i;
/*
* Reserve:
* Prio/gen writes first
@ -589,15 +507,5 @@ int bch_cache_allocator_init(struct cache *ca)
ca->watermark[WATERMARK_NONE] = ca->free.size / 2 +
ca->watermark[WATERMARK_MOVINGGC];
for (i = 0; i < MAX_IN_FLIGHT_DISCARDS; i++) {
struct discard *d = kzalloc(sizeof(*d), GFP_KERNEL);
if (!d)
return -ENOMEM;
d->ca = ca;
INIT_WORK(&d->work, discard_finish);
list_add(&d->list, &ca->discards);
}
return 0;
}

10
drivers/md/bcache/bcache.h
View File

@ -620,15 +620,6 @@ struct cache {
bool discard; /* Get rid of? */
/*
* We preallocate structs for issuing discards to buckets, and keep them
* on this list when they're not in use; do_discard() issues discards
* whenever there's work to do and is called by free_some_buckets() and
* when a discard finishes.
*/
atomic_t discards_in_flight;
struct list_head discards;
struct journal_device journal;
/* The rest of this all shows up in sysfs */
@ -1222,7 +1213,6 @@ int bch_btree_cache_alloc(struct cache_set *);
void bch_moving_init_cache_set(struct cache_set *);
int bch_cache_allocator_start(struct cache *ca);
void bch_cache_allocator_exit(struct cache *ca);
int bch_cache_allocator_init(struct cache *ca);
void bch_debug_exit(void);

4
drivers/md/bcache/super.c
View File

@ -1725,8 +1725,6 @@ void bch_cache_release(struct kobject *kobj)
if (ca->set)
ca->set->cache[ca->sb.nr_this_dev] = NULL;
bch_cache_allocator_exit(ca);
bio_split_pool_free(&ca->bio_split_hook);
free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca)));
@ -1758,8 +1756,6 @@ static int cache_alloc(struct cache_sb *sb, struct cache *ca)
__module_get(THIS_MODULE);
kobject_init(&ca->kobj, &bch_cache_ktype);
INIT_LIST_HEAD(&ca->discards);
bio_init(&ca->journal.bio);
ca->journal.bio.bi_max_vecs = 8;
ca->journal.bio.bi_io_vec = ca->journal.bio.bi_inline_vecs;