Shaohua Li d592a99691 raid5: add an option to avoid copy data from bio to stripe cache ... The stripe cache has two goals: 1. cache data, so next time if data can be found in stripe cache, disk access can be avoided. 2. stable data. data is copied from bio to stripe cache and calculated parity. data written to disk is from stripe cache, so if upper layer changes bio data, data written to disk isn't impacted. In my environment, I can guarantee 2 will not happen. And BDI_CAP_STABLE_WRITES can guarantee 2 too. For 1, it's not common too. block plug mechanism will dispatch a bunch of sequentail small requests together. And since I'm using SSD, I'm using small chunk size. It's rare case stripe cache is really useful. So I'd like to avoid the copy from bio to stripe cache and it's very helpful for performance. In my 1M randwrite tests, avoid the copy can increase the performance more than 30%. Of course, this shouldn't be enabled by default. It's reported enabling BDI_CAP_STABLE_WRITES can harm some workloads before, so I added an option to control it. Neilb: changed BUG_ON to WARN_ON Removed some assignments from raid5_build_block which are now not needed. Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: NeilBrown <neilb@suse.de>		2014-05-29 16:59:47 +10:00
..
bcache
persistent-data
bitmap.c	md/bitmap: remove confusing code from filemap_get_page.	2014-05-29 16:59:47 +10:00
bitmap.h
dm-bio-prison.c
dm-bio-prison.h
dm-bio-record.h
dm-bufio.c
dm-bufio.h
dm-builtin.c
dm-cache-block-types.h
dm-cache-metadata.c
dm-cache-metadata.h
dm-cache-policy-cleaner.c
dm-cache-policy-internal.h
dm-cache-policy-mq.c
dm-cache-policy.c
dm-cache-policy.h
dm-cache-target.c	dm cache: fix writethrough mode quiescing in cache_map	2014-05-01 16:14:24 -04:00
dm-crypt.c	dm crypt: fix cpu hotplug crash by removing per-cpu structure	2014-05-14 16:11:35 -04:00
dm-delay.c
dm-era-target.c
dm-exception-store.c
dm-exception-store.h
dm-flakey.c
dm-io.c
dm-ioctl.c
dm-kcopyd.c
dm-linear.c
dm-log-userspace-base.c
dm-log-userspace-transfer.c
dm-log-userspace-transfer.h
dm-log.c
dm-mpath.c	dm mpath: fix lock order inconsistency in multipath_ioctl	2014-05-14 16:12:17 -04:00
dm-mpath.h
dm-path-selector.c
dm-path-selector.h
dm-queue-length.c
dm-raid1.c
dm-raid.c
dm-region-hash.c
dm-round-robin.c
dm-service-time.c
dm-snap-persistent.c
dm-snap-transient.c
dm-snap.c
dm-stats.c
dm-stats.h
dm-stripe.c
dm-switch.c
dm-sysfs.c
dm-table.c
dm-target.c
dm-thin-metadata.c
dm-thin-metadata.h
dm-thin.c	dm thin: add timeout to stop out-of-data-space mode holding IO forever	2014-05-14 16:11:37 -04:00
dm-uevent.c
dm-uevent.h
dm-verity.c	dm verity: fix biovecs hash calculation regression	2014-04-15 12:19:24 -04:00
dm-zero.c
dm.c
dm.h
faulty.c
Kconfig
linear.c
linear.h
Makefile
md.c	md: md_clear_badblocks should return an error code on failure.	2014-05-29 16:59:46 +10:00
md.h	md/bitmap: don't abuse i_writecount for bitmap files.	2014-04-09 12:26:59 +10:00
multipath.c
multipath.h
raid0.c
raid0.h
raid1.c	md/raid1: r1buf_pool_alloc: free allocate pages when subsequent allocation fails.	2014-04-09 14:42:23 +10:00
raid1.h
raid5.c	raid5: add an option to avoid copy data from bio to stripe cache	2014-05-29 16:59:47 +10:00
raid5.h	raid5: add an option to avoid copy data from bio to stripe cache	2014-05-29 16:59:47 +10:00
raid10.c	md/raid10: call wait_barrier() for each request submitted.	2014-05-06 09:49:26 +10:00
raid10.h