Commit Graph

27 Commits

Author SHA1 Message Date
OGAWA Hirofumi
be3b075354 [PATCH] cfq: Further rbtree traversal and cfq_exit_queue() race fix
In current code, we are re-reading cic->key after dead cic->key check.
So, in theory, it may really re-read *after* cfq_exit_queue() seted NULL.

To avoid race, we copy it to stack, then use it. With this change, I
guess gcc will assign cic->key to a register or stack, and it wouldn't
be re-readed.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-04-18 19:18:31 +02:00
OGAWA Hirofumi
dbecf3ab40 [PATCH 2/2] cfq: fix cic's rbtree traversal
When queue dies, we set cic->key=NULL as dead mark. So, when we
traverse a rbtree, we must check whether it's still valid key. if it
was invalidated, drop it, then restart the traversal from top.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-04-18 09:45:18 +02:00
OGAWA Hirofumi
fba822722e [PATCH 1/2] iosched: fix typo and barrier()
On rmmod path, cfq/as waits to make sure all io-contexts was
freed. However, it's using complete(), not wait_for_completion().

I think barrier() is not enough in here. To avoid the following case,
this patch replaces barrier() with smb_wmb().

	cpu0			visibility			cpu1
	                [ioc_gnone=NULL,ioc_count=1]

ioc_gnone = &all_gone		NULL,ioc_count=1
atomic_read(&ioc_count)		NULL,ioc_count=1
wait_for_completion()		NULL,ioc_count=0	atomic_sub_and_test()
				NULL,ioc_count=0	if ( && ioc_gone)
						    [ioc_gone==NULL,
						    so doesn't call complete()]
			   &all_gone,ioc_count=0

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-04-18 09:44:06 +02:00
Jens Axboe
206dc69b31 [BLOCK] cfq-iosched: seek and async performance fixes
Detect whether a given process is seeky and if so disable (mostly) the
idle window if it is. We still allow just a little idle time, just enough
to allow that process to submit a new request. That is needed to maintain
fairness across priority groups.

In some cases, we could setup several async queues. This is not optimal
from a performance POV, since we want all async io in one queue to perform
good sorting on it. It also impacted sync queues, as async io got too much
slice time.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-03-28 13:03:44 +02:00
Andreas Mohr
e8a99053ea [PATCH] cfq-iosched: small cfq_choose_req() optimization
this is a small optimization to cfq_choose_req() in the CFQ I/O scheduler
(this function is a semi-often invoked candidate in an oprofile log):
by using a bit mask variable, we can use a simple switch() to check
the various cases instead of having to query two variables for each check.
Benefit: 251 vs. 285 bytes footprint of cfq_choose_req().
Also, common case 0 (no request wrapping) is now checked first in code.

Signed-off-by: Andreas Mohr <andi@lisas.de>
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-03-28 08:59:49 +02:00
Jens Axboe
e2d74ac066 [PATCH] [BLOCK] cfq-iosched: change cfq io context linking from list to tree
On setups with many disks, we spend a considerable amount of time
looking up the process-disk mapping on each queue of io. Testing with
a NULL based block driver, this costs 40-50% reduction in throughput
for 1000 disks.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-03-28 08:59:01 +02:00
Matthew Dobson
93d2341c75 [PATCH] mempool: use mempool_create_slab_pool()
Modify well over a dozen mempool users to call mempool_create_slab_pool()
rather than calling mempool_create() with extra arguments, saving about 30
lines of code and increasing readability.

Signed-off-by: Matthew Dobson <colpatch@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-26 08:57:00 -08:00
Al Viro
e572ec7e4e [PATCH] fix rmmod problems with elevator attributes, clean them up 2006-03-18 22:27:18 -05:00
Al Viro
3d1ab40f4c [PATCH] elevator_t lifetime rules and sysfs fixes 2006-03-18 18:35:43 -05:00
Al Viro
1cc9be68eb [PATCH] noise removal: cfq-iosched.c
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18 18:35:08 -05:00
Al Viro
a90d742e4c [PATCH] don't bother with refcounting for cfq_data
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18 18:35:05 -05:00
Al Viro
6f325a1344 [PATCH] fix cfq_get_queue()/ioprio_set(2) races
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18 18:34:17 -05:00
Al Viro
334e94de9b [PATCH] deal with rmmod/put_io_context() races
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18 18:34:15 -05:00
Al Viro
e17a9489b4 [PATCH] stop elv_unregister() from rogering other iosched's data, fix locking
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18 18:34:12 -05:00
Al Viro
25975f863b [PATCH] stop cfq from pinning queue down
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18 18:34:09 -05:00
Al Viro
d9ff418793 [PATCH] make cfq_exit_queue() prune the cfq_io_context for that queue
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18 18:34:07 -05:00
Al Viro
a6a0763a60 [PATCH] fix the exclusion for ioprio_set()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18 18:34:04 -05:00
Al Viro
12a0573215 [PATCH] keep sync and async cfq_queue separate
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18 18:34:02 -05:00
Al Viro
478a82b0ed [PATCH] switch to use of ->key to get cfq_data by cfq_io_context
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18 18:33:59 -05:00
Al Viro
7670876d2d [PATCH] stop leaking cfq_data in cfq_set_request()
We don't need to pin ->key down; ->cfqq->cfqd will do that for us.
Incidentally, that stops the leak we had - that reference was never
dropped.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18 18:33:56 -05:00
Al Viro
b0a6916bcc [PATCH] fix cfq hash lookups
If somebody does a hash lookup for cfq_queue while ioprio of an async queue
is elevated, they shouldn't end up stuck with lowered ioprio when we go back.
Fix is to use ->org_ioprio{,class} in hash lookups.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18 18:33:54 -05:00
Jens Axboe
7b14e3b52f [PATCH] cfq-iosched: slice expiry fixups
During testing of SLES10, we encountered a hang in the CFQ io scheduler.
Turns out the deferred slice expiry logic is buggy, so remove that for
now.  We could be left with an idle queue that would never wake up.  So
kill that logic, always expire immediately.  Also fix a potential timer
race condition.

Patch looks bigger than it is, because it moves a function.

Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-28 00:38:02 -08:00
Arjan van de Ven
64100099ed [BLOCK] mark some block/ variables cons
the patch below marks various read-only variables in block/* as const,
so that gcc can optimize the use of them; eg gcc will replace the use by
the value directly now and will even remove the memory usage of these.

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-01-06 09:46:02 +01:00
Coywolf Qi Hunt
eb97b73d75 [BLOCK] new block/ directory comment tidy
Some leftover comments referring to drivers/block that are now block/.
They don't add any information we don't already have, so kill them.

Signed-off-by: Coywolf Qi Hunt <qiyong@fc-cn.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-18 21:59:31 +01:00
Tejun Heo
b740d98f56 [BLOCK] cfq-iosched: fix slice_left calculation
When cfq slice expires, remainder of slice is calculated and stored in
cfqq->slice_left.  Current code calculates the opposite of remainder -
how many jiffies the cfqq has used past slice end.  This patch fixes
the bug.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12 10:56:36 +01:00
Tejun Heo
1b5ed5e1f1 [BLOCK] cfq-iosched: cfq forced dispatching fix
cfq forced dispatching might not return all requests on the queue.
This bug can hang elevator switchinig and corrupt request ordering
during flush sequence.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12 10:55:51 +01:00
Jens Axboe
3a65dfe8c0 [BLOCK] Move all core block layer code to new block/ directory
drivers/block/ is right now a mix of core and driver parts. Lets move
the core parts to a new top level directory. Al will move the fs/
related block parts to block/ next.

Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-04 08:43:35 +01:00