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c6ea41fbbe
linux-kernel-test/drivers/md
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Mikulas Patocka c6ea41fbbe dm kcopyd: preallocate sub jobs to avoid deadlock 
There's a possible theoretical deadlock in dm-kcopyd because multiple
allocations from the same mempool are required to finish a request.
Avoid this by preallocating sub jobs.

There is a mempool of 512 entries. Each request requires up to 9
entries from the mempool. If we have at least 57 concurrent requests
running, the mempool may overflow and mempool allocations may start
blocking until another entry is freed to the mempool. Because the same
thread is used to free entries to the mempool and allocate entries from
the mempool, this may result in a deadlock.

This patch changes it so that one mempool entry contains all 9 "struct
kcopyd_job" required to fulfill the whole request. The allocation is
done only once in dm_kcopyd_copy and no further mempool allocations are
done during request processing.

If dm_kcopyd_copy is not run in the completion thread, this
implementation is deadlock-free.

MIN_JOBS needs reducing accordingly and we've chosen to reduce it
further to 8.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-05-29 13:03:00 +01:00
..
bitmap.c md/bitmap: fix saving of events_cleared and other state. 2011-05-11 14:26:30 +10:00
bitmap.h Fix common misspellings 2011-03-31 11:26:23 -03:00
dm-bio-record.h
dm-crypt.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm 2011-03-25 20:51:44 -07:00
dm-delay.c dm: convert workqueues to alloc_ordered 2011-01-13 19:59:57 +00:00
dm-exception-store.c dm snapshot: test chunk size against both origin and snapshot 2010-08-12 04:13:51 +01:00
dm-exception-store.h dm snapshot: test chunk size against both origin and snapshot 2010-08-12 04:13:51 +01:00
dm-flakey.c dm: add flakey target 2011-03-24 13:54:24 +00:00
dm-io.c block: kill off REQ_UNPLUG 2011-03-10 08:52:27 +01:00
dm-ioctl.c dm ioctl: add flag to wipe buffers for secure data 2011-03-24 13:54:30 +00:00
dm-kcopyd.c dm kcopyd: preallocate sub jobs to avoid deadlock 2011-05-29 13:03:00 +01:00
dm-linear.c dm: use dm_target_offset macro 2010-08-12 04:14:11 +01:00
dm-log-userspace-base.c dm log userspace: add version number to comms 2011-01-13 19:59:52 +00:00
dm-log-userspace-transfer.c netlink: kill eff_cap from struct netlink_skb_parms 2011-03-03 13:32:07 -08:00
dm-log-userspace-transfer.h dm log: userspace add luid to distinguish between concurrent log instances 2009-09-04 20:40:34 +01:00
dm-log.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm 2011-03-25 20:51:44 -07:00
dm-mpath.c dm mpath: do not fail paths after integrity errors 2011-05-29 13:02:55 +01:00
dm-mpath.h
dm-path-selector.c dm: path selector use module refcount directly 2009-04-02 19:55:27 +01:00
dm-path-selector.h dm mpath: add start_io and nr_bytes to path selectors 2009-06-22 10:12:27 +01:00
dm-queue-length.c dm mpath: add queue length load balancer 2009-06-22 10:12:27 +01:00
dm-raid1.c block: remove per-queue plugging 2011-03-10 08:52:07 +01:00
dm-raid.c md/dm - remove remains of plug_fn callback. 2011-04-18 18:25:41 +10:00
dm-region-hash.c Fix common misspellings 2011-03-31 11:26:23 -03:00
dm-round-robin.c dm mpath: add start_io and nr_bytes to path selectors 2009-06-22 10:12:27 +01:00
dm-service-time.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
dm-snap-persistent.c dm snapshot: persistent make metadata_wq multithreaded 2011-01-13 19:59:59 +00:00
dm-snap-transient.c dm snapshot: move cow ref from exception store to snap core 2009-12-10 23:52:12 +00:00
dm-snap.c dm: fix opening log and cow devices for read only tables 2011-03-24 13:52:14 +00:00
dm-stripe.c dm stripe: implement merge method 2011-03-24 13:54:35 +00:00
dm-sysfs.c Driver core: Constify struct sysfs_ops in struct kobj_type 2010-03-07 17:04:49 -08:00
dm-table.c dm table: reject devices without request fns 2011-05-29 13:02:52 +01:00
dm-target.c dm: error return error for discards 2010-08-12 04:14:14 +01:00
dm-uevent.c dm table: remove dm_get from dm_table_get_md 2010-03-06 02:29:52 +00:00
dm-uevent.h
dm-zero.c dm: zero silently drop discards 2010-08-12 04:14:12 +01:00
dm.c block: fix non-atomic access to genhd inflight structures 2011-03-22 08:35:35 +01:00
dm.h block: Require subsystems to explicitly allocate bio_set integrity mempool 2011-03-17 11:11:05 +01:00
faulty.c Fix common misspellings 2011-03-31 11:26:23 -03:00
Kconfig dm: add flakey target 2011-03-24 13:54:24 +00:00
linear.c block: Require subsystems to explicitly allocate bio_set integrity mempool 2011-03-17 11:11:05 +01:00
linear.h md/linear: use call_rcu to free obsolete 'conf' structures. 2009-06-18 08:49:42 +10:00
Makefile dm: add flakey target 2011-03-24 13:54:24 +00:00
md.c md: allow resync_start to be set while an array is active. 2011-05-11 15:52:21 +10:00
md.h md: provide generic support for handling unplug callbacks. 2011-04-18 18:25:42 +10:00
multipath.c md: make error_handler functions more uniform and correct. 2011-05-11 14:38:44 +10:00
multipath.h md/multipath: discard ->working_disks in favour of ->degraded 2011-05-11 14:38:02 +10:00
raid0.c block: Require subsystems to explicitly allocate bio_set integrity mempool 2011-03-17 11:11:05 +01:00
raid0.h md: fix handling of array level takeover that re-arranges devices. 2010-06-24 13:33:24 +10:00
raid1.c md: allow resync_start to be set while an array is active. 2011-05-11 15:52:21 +10:00
raid1.h md/raid1: improve handling of pages allocated for write-behind. 2011-05-11 14:51:19 +10:00
raid5.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-05-23 09:12:26 -07:00
raid5.h md - remove old plugging code. 2011-04-18 18:25:42 +10:00
raid10.c md/raid10: reformat some loops with less indenting. 2011-05-11 14:54:41 +10:00
raid10.h Fix common misspellings 2011-03-31 11:26:23 -03:00