Vishal Verma 5212e11fde nd_btt: atomic sector updates ... BTT stands for Block Translation Table, and is a way to provide power fail sector atomicity semantics for block devices that have the ability to perform byte granularity IO. It relies on the capability of libnvdimm namespace devices to do byte aligned IO. The BTT works as a stacked blocked device, and reserves a chunk of space from the backing device for its accounting metadata. It is a bio-based driver because all IO is done synchronously, and there is no queuing or asynchronous completions at either the device or the driver level. The BTT uses 'lanes' to index into various 'on-disk' data structures, and lanes also act as a synchronization mechanism in case there are more CPUs than available lanes. We did a comparison between two lane lock strategies - first where we kept an atomic counter around that tracked which was the last lane that was used, and 'our' lane was determined by atomically incrementing that. That way, for the nr_cpus > nr_lanes case, theoretically, no CPU would be blocked waiting for a lane. The other strategy was to use the cpu number we're scheduled on to and hash it to a lane number. Theoretically, this could block an IO that could've otherwise run using a different, free lane. But some fio workloads showed that the direct cpu -> lane hash performed faster than tracking 'last lane' - my reasoning is the cache thrash caused by moving the atomic variable made that approach slower than simply waiting out the in-progress IO. This supports the conclusion that the driver can be a very simple bio-based one that does synchronous IOs instead of queuing. Cc: Andy Lutomirski <luto@amacapital.net> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jens Axboe <axboe@fb.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Neil Brown <neilb@suse.de> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Greg KH <gregkh@linuxfoundation.org> [jmoyer: fix nmi watchdog timeout in btt_map_init] [jmoyer: move btt initialization to module load path] [jmoyer: fix memory leak in the btt initialization path] [jmoyer: Don't overwrite corrupted arenas] Signed-off-by: Vishal Verma <vishal.l.verma@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>		2015-06-26 11:23:38 -04:00
..
ABI	platform-drivers-x86 for 4.1	2015-04-26 13:44:46 -07:00
accounting	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
acpi	ACPI / documentation: Fix ambiguity in the GPIO properties document	2015-05-04 14:26:14 +02:00
aoe
arm	ARM: SoC multiplatform code changes for v4.1	2015-04-22 09:20:15 -07:00
arm64	ARM64 / ACPI: additions of ACPI documentation for arm64	2015-03-26 15:13:09 +00:00
auxdisplay	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
backlight
blackfin	Documentation: blackfin: Makefile: Typo building issue	2015-04-11 15:19:31 +02:00
block	Documentation: Remove mentioning of block barriers	2015-03-20 07:41:56 -06:00
blockdev	Merge branch 'for-4.1/drivers' of git://git.kernel.dk/linux-block	2015-04-16 22:05:27 -04:00
bus-devices
cdrom
cgroups	The documentation tree update for 4.1. Numerous fixes, the overdue removal	2015-04-18 11:10:49 -04:00
cma	cma: debug: document new debugfs interface	2015-04-14 16:49:00 -07:00
connector	w1: optional bundling of netlink kernel replies	2014-05-27 13:56:21 -07:00
console
cpu-freq	intel_pstate: Add num_pstates to sysfs	2015-01-30 01:52:17 +01:00
cpuidle
cris
crypto	crypto: doc - AEAD / RNG AF_ALG interface	2015-03-09 21:06:18 +11:00
development-process	Documentation: remove outdated references to the linux-next wiki	2014-10-28 09:06:11 -04:00
device-mapper	dm crypt: update URLs to new cryptsetup project page	2015-04-15 12:10:24 -04:00
devicetree	ARM: SoC fixes for 4.1-rc2	2015-05-09 16:13:38 -07:00
dmaengine	Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma	2015-02-18 08:49:20 -08:00
DocBook	Merge branch 'drm-next-merged' of git://people.freedesktop.org/~airlied/linux into v4l_for_linus	2015-04-21 09:44:55 -03:00
driver-model	Char/Misc driver patches for 4.1-rc1	2015-04-21 09:42:58 -07:00
dvb	[media] get_dvb_firmware: Update firmware of ITEtech IT9135	2014-09-21 17:03:04 -03:00
early-userspace
EDID	drm: Add 800x600 (SVGA) screen resolution to the built-in EDIDs	2014-05-26 12:53:40 +10:00
extcon
fault-injection
fb
filesystems	xfs: update for 4.1-rc1	2015-04-24 07:08:41 -07:00
firmware_class	doc: fix minor typos in firmware_class README	2014-07-17 18:43:40 -07:00
fmc
frv
gpio	The documentation tree update for 4.1. Numerous fixes, the overdue removal	2015-04-18 11:10:49 -04:00
hid	HID: sensor: Update document for custom sensor	2015-04-10 22:22:56 +02:00
hwmon	hwmon: (it87) Add support for IT8620E	2015-04-05 06:01:00 -07:00
i2c	i2c: slave: add documentation for i2c-slave-eeprom	2015-03-27 16:53:39 +01:00
ia64	virtual: Documentation: simplify and generalize paravirt_ops.txt	2015-02-13 17:15:44 +10:30
ide
infiniband	IB/mad: add new ioctl to ABI to support new registration options	2014-08-10 20:36:00 -07:00
input	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input	2015-04-21 12:54:08 -07:00
ioctl	platform/chrome: Add Chrome OS EC userspace device interface	2015-02-26 15:45:06 -08:00
isdn
ja_JP
kbuild	Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild	2015-02-19 10:31:37 -08:00
kdump	kernel: add panic_on_warn	2014-12-10 17:41:10 -08:00
ko_KR
laptops	thinkpad_acpi: Add adaptive_kbd_mode sysfs attr	2015-03-03 09:00:08 -08:00
leds	Documentation: leds: Add description of LED Flash class extension	2015-03-09 17:18:00 -07:00
locking	Documentation changes for 3.20	2015-02-11 13:03:11 -08:00
m68k
memory-devices
metag
mic	Documentation: Build mic/mpssd only for x86_64	2014-12-05 11:18:36 -05:00
mips	Documentation: au1xxx-ide.c has moved	2014-08-26 09:35:53 +02:00
misc-devices	Documentation/misc-devices/mei: Fix indentation of embedded code.	2015-01-29 12:56:20 -07:00
mmc
mn10300
mtd	MTD updates for 3.16:	2014-06-11 08:35:34 -07:00
namespaces
netlabel
networking	net: rfs: fix crash in get_rps_cpus()	2015-04-26 16:07:57 -04:00
nfc
nios2	Documentation: Add documentation for Nios2 architecture	2014-12-08 12:56:06 +08:00
nvdimm	nd_btt: atomic sector updates	2015-06-26 11:23:38 -04:00
parisc
PCI	The documentation tree update for 4.1. Numerous fixes, the overdue removal	2015-04-18 11:10:49 -04:00
pcmcia	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
phy
platform	Documentation: Add list of laptop models supported by the Compal driver	2014-06-10 19:11:06 -04:00
power	Power management and ACPI updates for v4.1-rc1	2015-04-14 20:21:54 -07:00
powerpc	Revert "powerpc/tm: Abort syscalls in active transactions"	2015-04-30 15:24:58 +10:00
pps
prctl	Documentation: Restrict TSC test code to x86	2014-10-28 08:46:27 -04:00
pti
ptp	ptp: restore the makefile for building the test program.	2014-10-24 16:07:10 -04:00
rapidio	rapidio/tsi721_dma: rework scatter-gather list handling	2014-08-08 15:57:24 -07:00
RCU	Merge branches 'doc.2015.01.07a', 'fixes.2015.01.15a', 'preempt.2015.01.06a', 'srcu.2015.01.06a', 'stall.2015.01.16a' and 'torture.2015.01.11a' into HEAD	2015-01-15 23:34:34 -08:00
s390	s390/docs: Remove section about script debugging from Debugging390.txt	2015-01-15 11:11:14 +01:00
scheduler	docs/completion.txt: Various tweaks and corrections	2015-04-04 15:20:26 +02:00
scsi	genirq: Remove the deprecated 'IRQF_DISABLED' request_irq() flag entirely	2015-03-05 20:53:06 +01:00
security	Smack: Updates for Smack documentation	2015-03-31 10:35:31 -07:00
serial	serial: Fix locking for uart driver set_termios() method	2014-11-05 18:53:54 -08:00
sh
sound	ASoC: Updates for v4.1	2015-04-13 14:14:29 +02:00
spi	Documentation/spi/spidev_test.c: fix warning	2015-04-17 09:04:12 -04:00
sysctl	Doc/sysctl/kernel.txt: document threads-max	2015-04-17 09:04:07 -04:00
target	target: Version 2 of TCMU ABI	2015-04-19 22:40:26 -07:00
thermal	Documentation: thermal: document of_cpufreq_cooling_register()	2015-01-06 14:39:17 -04:00
timers	documentation: Update NO_HZ_FULL interaction with POSIX timers	2015-02-26 11:57:29 -08:00
tpm
trace	coresight: Correcting documentation typographical error	2015-04-03 16:17:03 +02:00
usb	usb: patches for v4.1 merge window	2015-03-24 22:57:49 +01:00
vDSO	vdso: don't require 64-bit math in standalone test	2014-10-25 10:53:44 -04:00
video4linux	[media] media/Documentation: New flag EXECUTE_ON_WRITE	2015-04-08 06:35:16 -03:00
virtual	KVM: PPC: Book3S HV: Add fast real-mode H_RANDOM implementation.	2015-04-21 15:21:29 +02:00
vm	The documentation tree update for 4.1. Numerous fixes, the overdue removal	2015-04-18 11:10:49 -04:00
w1	w1: new w1_ds2406 driver	2014-06-19 17:45:14 -07:00
watchdog	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
wimax
x86	x86/mm/KASLR: Propagate KASLR status to kernel proper	2015-04-03 15:26:15 +02:00
xtensa
zh_CN	Documentation:Update Documentation/zh_CN/arm64/memory.txt	2015-04-04 15:20:26 +02:00
00-INDEX	Update of Documentation/dmaengine/00-INDEX	2014-12-29 15:28:24 -07:00
applying-patches.txt	Documentation: change "&" to "and" in Documentation/applying-patches.txt	2014-09-26 11:10:11 +02:00
assoc_array.txt
atomic_ops.txt	documentation: Clarify memory-barrier semantics of atomic operations	2015-02-26 11:57:31 -08:00
bad_memory.txt
basic_profiling.txt
bcache.txt
binfmt_misc.txt	binfmt_misc: touch up documentation a bit	2014-10-14 02:18:16 +02:00
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt	rmap: drop support of non-linear mappings	2015-02-10 14:30:31 -08:00
Changes	Documentation: GNU is frequently spelled Gnu	2014-12-29 15:33:17 -07:00
circular-buffers.txt
clk.txt	clk: Add rate constraints to clocks	2015-02-02 14:23:42 -08:00
coccinelle.txt
CodeOfConflict	Code of Conflict	2015-02-27 11:44:24 -08:00
CodingStyle	The documentation tree update for 4.1. Numerous fixes, the overdue removal	2015-04-18 11:10:49 -04:00
cpu-hotplug.txt	cpumask: fix cpu-hotplug documentation	2015-03-05 13:37:01 +10:30
cpu-load.txt
cputopology.txt
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt	firewire: revert to 4 GB RDMA, fix protocols using Memory Space	2014-05-29 15:50:30 +02:00
dell_rbu.txt
devices.txt
digsig.txt
DMA-API-HOWTO.txt	Documentation: correct parameter error for dma_mapping_error	2014-09-26 11:22:29 +02:00
DMA-API.txt	DMA-API: Capitalize "CPU" consistently	2014-05-26 17:28:27 -06:00
DMA-attributes.txt
dma-buf-sharing.txt	dma-buf: cleanup dma_buf_export() to make it easily extensible	2015-04-21 14:47:16 +05:30
DMA-ISA-LPC.txt
dontdiff
dynamic-debug-howto.txt
edac.txt	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial into next	2014-06-04 08:50:34 -07:00
efi-stub.txt
eisa.txt
email-clients.txt	Documentation/email-clients.txt: Fix one grammar mistake, add extra info about TB	2015-03-20 07:41:55 -06:00
flexible-arrays.txt
futex-requeue-pi.txt	doc: Fix misnamed FUTEX_CMP_REQUEUE_PI op constants	2015-01-19 12:05:32 +01:00
gcov.txt
gdb-kernel-debugging.txt	scripts/gdb: add basic documentation	2015-02-17 14:34:54 -08:00
highuid.txt
HOWTO	Documentation: remove outdated references to the linux-next wiki	2014-10-28 09:06:11 -04:00
hsi.txt
hw_random.txt
hwspinlock.txt
init.txt
initrd.txt
intel_txt.txt
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt	ipmi:ssif: Ignore spaces when comparing I2C adapter names	2015-05-05 14:24:45 -05:00
IRQ-affinity.txt
IRQ-domain.txt	IRQCHIP: Update docs regarding irq_domain_add_tree()	2015-04-01 17:21:35 +02:00
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt	Documentation: update java sample wrapper for java 7	2014-05-25 12:39:00 -07:00
kasan.txt	kasan: show gcc version requirements in Kconfig and Documentation	2015-05-05 17:10:10 -07:00
kernel-doc-nano-HOWTO.txt
kernel-docs.txt
kernel-parameters.txt	uas: Add US_FL_MAX_SECTORS_240 flag	2015-04-28 12:48:57 +02:00
kernel-per-CPU-kthreads.txt	documentation: Update per-CPU kthreads documentation	2015-02-26 11:57:30 -08:00
kmemcheck.txt	Documentation: update the CONFIG_DEBUG_PAGEALLOC description	2015-03-20 07:41:55 -06:00
kmemleak.txt	Documentation: Add CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF case	2014-10-24 13:59:03 -04:00
kobject.txt	kobject: grammar fix	2014-12-08 09:07:11 -05:00
kprobes.txt	kprobes: Update Documentation/kprobes.txt	2015-03-20 07:41:55 -06:00
kref.txt
kselftest.txt	kselftest: Move the docs to the Documentation dir	2014-11-24 10:49:54 -07:00
ldm.txt
local_ops.txt	percpu: update local_ops.txt to reflect this_cpu operations	2014-12-13 12:42:53 -08:00
lockup-watchdogs.txt	lockup-watchdogs: Fix a typo	2014-08-26 09:35:52 +02:00
logo.gif
logo.txt
lzo.txt	Documentation: lzo: document part of the encoding	2014-09-28 11:08:00 +02:00
magic-number.txt
mailbox.txt	Documentation: Fix a typo in mailbox.txt	2014-11-03 11:54:50 -05:00
Makefile	Documentation: Remove ZBOOT MMC/SDHI utility and docs	2015-02-24 06:45:25 +09:00
ManagementStyle
md-cluster.txt	md-cluster: Design Documentation	2015-02-23 07:16:46 -06:00
md.txt
media-framework.txt
memory-barriers.txt	The documentation tree update for 4.1. Numerous fixes, the overdue removal	2015-04-18 11:10:49 -04:00
memory-hotplug.txt	mem-hotplug: fix typo in Documentation/memory-hotplug.txt	2015-03-20 07:41:55 -06:00
module-signing.txt	modsign: change default key details	2015-04-30 09:35:41 -07:00
mono.txt
nommu-mmap.txt	fs: introduce f_op->mmap_capabilities for nommu mmap support	2015-01-20 14:02:58 -07:00
numastat.txt
oops-tracing.txt	livepatch: kernel: add TAINT_LIVEPATCH	2014-12-22 15:40:48 +01:00
padata.txt
parport-lowlevel.txt
parport.txt
percpu-rw-semaphore.txt
phy.txt	phy: improved lookup method	2014-11-21 19:48:50 +05:30
pi-futex.txt
pinctrl.txt	pinctrl: fix example .get_group_pins implementation signature	2015-03-18 02:02:20 +01:00
pnp.txt
preempt-locking.txt
printk-formats.txt	The documentation tree update for 4.1. Numerous fixes, the overdue removal	2015-04-18 11:10:49 -04:00
pwm.txt
ramoops.txt	pstore-ram: Allow optional mapping with pgprot_noncached	2014-12-11 13:38:31 -08:00
rbtree.txt
remoteproc.txt
rfkill.txt	rfkill: document rfkill module parameters	2015-01-09 23:22:12 +01:00
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
rtc.txt	Documentation, split up rtc.txt into documentation and test file	2015-03-24 22:01:58 -06:00
SAK.txt
SecurityBugs
serial-console.txt
sgi-ioc4.txt
SM501.txt
smsc_ece1099.txt
sparse.txt
stable_api_nonsense.txt
stable_kernel_rules.txt	stable_kernel_rules: Add clause about specification of kernel versions to patch.	2015-03-26 23:52:24 +01:00
static-keys.txt
SubmitChecklist
SubmittingDrivers	doc: SubmittingPatches: remove dead link, kerneltrap.org no longer works	2014-06-19 15:15:27 +02:00
SubmittingPatches	checkpatch, SubmittingPatches: suggest line wrapping commit messages at 75 columns	2015-04-17 09:03:57 -04:00
svga.txt
sysfs-rules.txt	Documentation/sysfs-rules.txt: Add device attribute error code documentation	2014-09-19 14:44:51 -07:00
sysrq.txt
this_cpu_ops.txt	Docs: this_cpu_ops: remove redundant add forms	2014-09-26 11:03:00 +02:00
unaligned-memory-access.txt
unicode.txt
unshare.txt
vfio.txt	drivers/vfio: EEH support for VFIO PCI device	2014-08-05 15:28:48 +10:00
VGA-softcursor.txt
vgaarbiter.txt
video-output.txt
vme_api.txt
volatile-considered-harmful.txt
workqueue.txt
xillybus.txt	xillybus: Move out of staging	2014-09-23 23:44:16 -07:00
xz.txt
zorro.txt