linux-stable-rt/drivers/md
NeilBrown 6ed3003c19 md: fix an occasional deadlock in raid5
raid5's 'make_request' function calls generic_make_request on underlying
devices and if we run out of stripe heads, it could end up waiting for one of
those requests to complete.  This is bad as recursive calls to
generic_make_request go on a queue and are not even attempted until
make_request completes.

So: don't make any generic_make_request calls in raid5 make_request until all
waiting has been done.  We do this by simply setting STRIPE_HANDLE instead of
calling handle_stripe().

If we need more stripe_heads, raid5d will get called to process the pending
stripe_heads which will call generic_make_request from a

This change by itself causes a performance hit.  So add a change so that
raid5_activate_delayed is only called at unplug time, never in raid5.  This
seems to bring back the performance numbers.  Calling it in raid5d was
sometimes too soon...

Neil said:

  How about we queue it for 2.6.25-rc1 and then about when -rc2 comes out,
  we queue it for 2.6.24.y?

Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Tested-by: dean gaudet <dean@arctic.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06 10:41:19 -08:00
..
raid6test md: raid6: clean up the style of raid6test/test.c 2008-02-06 10:41:18 -08:00
.gitignore
Kconfig
Makefile
bitmap.c md: change ITERATE_RDEV to rdev_for_each 2008-02-06 10:41:19 -08:00
dm-bio-list.h
dm-bio-record.h
dm-crypt.c
dm-delay.c
dm-emc.c
dm-exception-store.c
dm-hw-handler.c
dm-hw-handler.h
dm-io.c
dm-io.h
dm-ioctl.c
dm-linear.c
dm-log.c
dm-log.h
dm-mpath-hp-sw.c
dm-mpath-rdac.c
dm-mpath.c
dm-mpath.h
dm-path-selector.c
dm-path-selector.h
dm-raid1.c
dm-round-robin.c
dm-snap.c
dm-snap.h
dm-stripe.c
dm-table.c
dm-target.c
dm-uevent.c
dm-uevent.h
dm-zero.c
dm.c
dm.h
faulty.c md: change ITERATE_RDEV to rdev_for_each 2008-02-06 10:41:19 -08:00
kcopyd.c
kcopyd.h
linear.c md: change ITERATE_RDEV to rdev_for_each 2008-02-06 10:41:19 -08:00
md.c md: change ITERATE_RDEV_GENERIC to rdev_for_each_list, and remove ITERATE_RDEV_PENDING. 2008-02-06 10:41:19 -08:00
mktables.c
multipath.c md: change ITERATE_RDEV to rdev_for_each 2008-02-06 10:41:19 -08:00
raid0.c md: change ITERATE_RDEV to rdev_for_each 2008-02-06 10:41:19 -08:00
raid1.c md: change ITERATE_RDEV to rdev_for_each 2008-02-06 10:41:19 -08:00
raid5.c md: fix an occasional deadlock in raid5 2008-02-06 10:41:19 -08:00
raid6.h
raid6algos.c
raid6altivec.uc
raid6int.uc
raid6mmx.c
raid6recov.c
raid6sse1.c
raid6sse2.c
raid6x86.h
raid10.c md: change ITERATE_RDEV to rdev_for_each 2008-02-06 10:41:19 -08:00
unroll.pl