Commit graph

69 commits

Author SHA1 Message Date
Jens Axboe
bb37b94c68 [BLOCK] Cleanup unused variable passing
- ->init_queue() does not need the elevator passed in
- ->put_request() is a hot path and need not have the queue passed in
- cfq_update_io_seektime() does not need cfqd passed in

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2006-12-01 10:42:33 +01:00
Jens Axboe
5fccbf61be [PATCH] CFQ: request <-> request merging rr_list fixup
In very rare circumstances would we be pruning a merged request and at
the same time delete the implicated cfqq from the rr_list, and not readd
it when the merged request got added. This could cause io stalls until
that process issued io again.

Fix it up by putting the rr_list add handling into cfq_add_rq_rb(),
identical to how pruning is handled in cfq_del_rq_rb(). This fixes a
hang reproducible with fsx-linux.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-31 08:12:45 -08:00
Jens Axboe
c1b707d253 [PATCH] CFQ: bad locking in changed_ioprio()
When the ioprio code recently got juggled a bit, a bug was introduced.
changed_ioprio() is no longer called with interrupts disabled, so using
plain spin_lock() on the queue_lock is a bug.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-30 11:01:50 -08:00
Jens Axboe
0261d6886e [PATCH] CFQ: use irq safe locking in cfq_cic_link()
If cfq_set_request() is called for a new process AND a non-fs io
request (so that __GFP_WAIT may not be set), cfq_cic_link() may
use spin_lock_irq() and spin_unlock_irq() with interrupts already
disabled.

Fix is to always use irq safe locking in cfq_cic_link()

Acked-By: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-30 10:21:58 -08:00
Peter Zijlstra
6e9a4738c9 [PATCH] completions: lockdep annotate on stack completions
All on stack DECLARE_COMPLETIONs should be replaced by:
DECLARE_COMPLETION_ONSTACK

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-01 00:39:24 -07:00
Jens Axboe
0fe2347957 [PATCH] Update axboe@suse.de email address
As people often look for the copyright in files to see who to mail,
update the link to a neutral one.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:34 +02:00
Jens Axboe
374f84ac39 [PATCH] cfq-iosched: use metadata read flag
Give meta data reads preference over regular reads, as the process
often needs to get that out of the way to do the io it was actually
interested in.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:43 +02:00
Jens Axboe
bf57225670 [PATCH] cfq-iosched: improve queue preemption
Don't touch the current queues, just make sure that the wanted queue
is selected next. Simplifies the logic.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:41 +02:00
Jens Axboe
dc72ef4ae3 [PATCH] Add blk_start_queueing() helper
CFQ implements this on its own now, but it's really block layer
knowledge. Tells a device queue to start dispatching requests to
the driver, taking care to unplug if needed. Also fixes the issue
where as/cfq will invoke a stopped queue, which we really don't
want.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:40 +02:00
Jens Axboe
981a79730d [PATCH] cfq-iosched: kill the empty_list
No point in having a place holder list just for empty queues, so remove
it. It's not used for anything other than to keep ->cfq_list busy.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:40 +02:00
Jens Axboe
53b03744e5 [PATCH] cfq-iosched: Kill O(N) runtime of cfq_resort_rr_list()
Currently it scales with number of processes in that priority group,
which is potentially not very nice as it's called quite often.
Basically we always need to do tail inserts, except for the case of a
new process. So just mark/detect a queue as such.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:39 +02:00
Jens Axboe
b5deef9012 [PATCH] Make sure all block/io scheduler setups are node aware
Some were kmalloc_node(), some were still kmalloc(). Change them all to
kmalloc_node().

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:39 +02:00
Jens Axboe
1ea25ecb72 [PATCH] Audit block layer inlines
Kill a few inlines that bring in too much code to more than one location
Shrinks kernel text by about 300 bytes on 32-bit x86.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:38 +02:00
Jens Axboe
4050cf1674 [PATCH] cfq-iosched: use new io context counting mechanism
It's ok if the read path is a lot more costly, as long as inc/dec is
really cheap. The inc/dec will happen for each created/freed io context,
while the reading only happens when a disk queue exits.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:37 +02:00
Jens Axboe
fc46379daf [PATCH] cfq-iosched: kill cfq_exit_lock
cfq_exit_lock is protecting two things now:

- The per-ioc rbtree of cfq_io_contexts

- The per-cfqd linked list of cfq_io_contexts

The per-cfqd linked list can be protected by the queue lock, as it is (by
definition) per cfqd as the queue lock is.

The per-ioc rbtree is mainly used and updated by the process itself only.
The only outside use is the io priority changing. If we move the
priority changing to not browsing the rbtree, we can remove any locking
from the rbtree updates and lookup completely. Let the sys_ioprio syscall
just mark processes as having the iopriority changed and lazily update
the private cfq io contexts the next time io is queued, and we can
remove this locking as well.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:36 +02:00
Jens Axboe
89850f7ee9 [PATCH] cfq-iosched: cleanups, fixes, dead code removal
A collection of little fixes and cleanups:

- We don't use the 'queued' sysfs exported attribute, since the
  may_queue() logic was rewritten. So kill it.

- Remove dead defines.

- cfq_set_active_queue() can be rewritten cleaner with else if conditions.

- Several places had cfq_exit_cfqq() like logic, abstract that out and
  use that.

- Annotate the cfqq kmem_cache_alloc() so the allocator knows that this
  is a repeat allocation if it fails with __GFP_WAIT set. Allows the
  allocator to start freeing some memory, if needed. CFQ already loops for
  this condition, so might as well pass the hint down.

- Remove cfqd->rq_starved logic. It's not needed anymore after we dropped
  the crq allocation in cfq_set_request().

- Remove uneeded parameter passing.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:35 +02:00
Jens Axboe
cb78b285c8 [PATCH] Drop useless bio passing in may_queue/set_request API
It's not needed for anything, so kill the bio passing.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:23 +02:00
Jens Axboe
5e70537479 [PATCH] cfq-iosched: kill crq
Get rid of the cfq_rq request type. With the added elevator_private2, we
have enough room in struct request to get rid of any crq allocation/free
for each request.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:27:02 +02:00
Jens Axboe
5380a101d3 [PATCH] cfq-iosched: remove the crq flag functions/variable
There's just one flag currently (SYNC), and that one can be grabbed from
the request.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:27:01 +02:00
Jens Axboe
95e8810b28 [PATCH] cfq-iosched: convert to using the FIFO elevator defines
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:26:59 +02:00
Jens Axboe
21183b07ee [PATCH] cfq-iosched: migrate to using the elevator rb functions
This removes the rbtree handling from CFQ.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:26:58 +02:00
Jens Axboe
9817064b68 [PATCH] elevator: move the backmerging logic into the elevator core
Right now, every IO scheduler implements its own backmerging (except for
noop, which does no merging). That results in duplicated code for
essentially the same operation, which is never a good thing. This patch
moves the backmerging out of the io schedulers and into the elevator
core. We save 1.6kb of text and as a bonus get backmerging for noop as
well. Win-win!

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:26:56 +02:00
Oleg Nesterov
be33c3a67b [PATCH] cfq_cic_link: fix usage of wrong cfq_io_context
Obviously, cfq_cic_link() shouldn't free a just allocated cfq_io_context?
The dead key is from __cic, so drop that.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-08-21 10:02:54 +02:00
Jens Axboe
44eb123126 [PATCH] cfq-iosched: don't use a hard jiffies value, translate from msecs
The CIC_SEEKY() test really wants to use the minimum of either:

- 2 msecs (not jiffies)

- or, the pending slice time

So code it like that.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-07-25 15:05:21 +02:00
Jörn Engel
6ab3d5624e Remove obsolete #include <linux/config.h>
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-30 19:25:36 +02:00
Jens Axboe
dd67d05152 [PATCH] rbtree: support functions used by the io schedulers
They all duplicate macros to check for empty root and/or node, and
clearing a node. So put those in rbtree.h.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-06-23 17:10:39 +02:00
Jens Axboe
fd61af0384 [PATCH] cfq-iosched: rq update fixes
- Remember to set ->last_sector so that the cfq_choose_req() logic
  works correctly.

- Remove redundant call to cfq_choose_req()

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-06-23 17:10:39 +02:00
Jens Axboe
caaa5f9f0a [PATCH] cfq-iosched: many performance fixes
This is a collection of patches that greatly improve CFQ performance
in some circumstances.

- Change the idling logic to only kick in after a request is done and we
  are deciding what to do. Before the idling included the request service
  time, so it was hard to adjust. Now it's true think/idle time.

- Take advantage of TCQ/NCQ/queueing for seeky sync workloads, but keep
  it in control for sync and sequential (or close to) workloads.

- Expire queues immediately and move on to other busy queues, if we are
  not going to idle after the current one finishes.

- Don't rearm idle timer if there are no busy queues. Just leave the
  system idle.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-06-23 17:10:39 +02:00
Jens Axboe
35e6077cb1 [PATCH] cfq-iosched: correctly set ioprio on both targets
Patch originally from Vasily Tarasov <vtaras@sw.ru>

If you set io-priority of process 1 using sys_ioprio_set system call by
another process 2 (like ionice do), then cfq_init_prio_data() function
sets priority of process 2 (current) on queue of process 1 and clears
the flag, that designates change of ioprio.  So the process  1 will work
like with priority of process 2.

I propose not to call cfq_init_prio_data() on io-priority change, but
only mark queue as queue with changed prority.  Every time when new
request comes cfq-scheduler checks for this flag and atomaticaly changes
priority of queue to new value.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-06-23 17:10:39 +02:00
Jens Axboe
b31dc66a54 [PATCH] Kill PF_SYNCWRITE flag
A process flag to indicate whether we are doing sync io is incredibly
ugly. It also causes performance problems when one does a lot of async
io and then proceeds to sync it. Part of the io will go out as async,
and the other part as sync. This causes a disconnect between the
previously submitted io and the synced io. For io schedulers such as CFQ,
this will cause us lost merges and suboptimal behaviour in scheduling.

Remove PF_SYNCWRITE completely from the fsync/msync paths, and let
the O_DIRECT path just directly indicate that the writes are sync
by using WRITE_SYNC instead.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-06-23 17:10:39 +02:00
Jens Axboe
271f18f102 [PATCH] cfq-iosched: Don't set the queue batching limits
We cannot update them if the user changes nr_requests, so don't
set it in the first place. The gains are pretty questionable as
well. The batching loss has been shown to decrease throughput.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-06-23 17:10:38 +02:00
Linus Torvalds
6b41fd1785 Fix up CFQ scheduler for recent rbtree node shrinkage
The color is now in the low bits of the parent pointer, and initializing
it to 0 happens as part of the whole memset above, so just remove the
unnecessary RB_CLEAR_COLOR.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-20 19:44:03 -07:00
Linus Torvalds
2edc322d42 Merge git://git.infradead.org/~dwmw2/rbtree-2.6
* git://git.infradead.org/~dwmw2/rbtree-2.6:
  [RBTREE] Switch rb_colour() et al to en_US spelling of 'color' for consistency
  Update UML kernel/physmem.c to use rb_parent() accessor macro
  [RBTREE] Update hrtimers to use rb_parent() accessor macro.
  [RBTREE] Add explicit alignment to sizeof(long) for struct rb_node.
  [RBTREE] Merge colour and parent fields of struct rb_node.
  [RBTREE] Remove dead code in rb_erase()
  [RBTREE] Update JFFS2 to use rb_parent() accessor macro.
  [RBTREE] Update eventpoll.c to use rb_parent() accessor macro.
  [RBTREE] Update key.c to use rb_parent() accessor macro.
  [RBTREE] Update ext3 to use rb_parent() accessor macro.
  [RBTREE] Change rbtree off-tree marking in I/O schedulers.
  [RBTREE] Add accessor macros for colour and parent fields of rb_node
2006-06-20 14:51:22 -07:00
Jens Axboe
553698f944 [PATCH] cfq-iosched: fix crash in do_div()
We don't clear the seek stat values in cfq_alloc_io_context(), and if
->seek_mean is unlucky enough to be set to -36 by chance, the first
invocation of cfq_update_io_seektime() will oops with a divide by zero
in do_div().

Just memset the entire cic instead of filling invididual values
independently.

Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-14 10:22:16 -07:00
Jens Axboe
bc1c116974 [PATCH] elevator switching race
There's a race between shutting down one io scheduler and firing up the
next, in which a new io could enter and cause the io scheduler to be
invoked with bad or NULL data.

To fix this, we need to maintain the queue lock for a bit longer.
Unfortunately we cannot do that, since the elevator init requires to be
run without the lock held.  This isn't easily fixable, without also
changing the mempool API.  So split the initialization into two parts,
and alloc-init operation and an attach operation.  Then we can
preallocate the io scheduler and related structures, and run the attach
inside the lock after we detach the old one.

This patch has survived 30 minutes of 1 second io scheduler switching
with a very busy io load.

Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-08 15:14:23 -07:00
Jens Axboe
b52a834892 [PATCH] cfq-iosched: busy_rr fairness fix
Now that we select busy_rr for possible service, insert entries at the
back of that list instead of at the front.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-06-01 18:53:43 +02:00
Jens Axboe
ae818a38d4 [PATCH] cfq-iosched: fix bug in timer handling for the idle class
There's a small window from when the timer is entered and we grab
the queue lock, where cfq_set_active_queue() could be rearming the
timer for us. Seen in the wild on a 12-way ppc box. Fix this by
just using mod_timer(), which will do the right thing for us.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-06-01 10:13:43 +02:00
Jens Axboe
25776e3594 [PATCH] cfq-iosched: Detect hardware queueing
If the hardware is doing real queueing, decide that it's worthless to
idle the hardware. It does reasonable simultaneous io in that case
anyways, and the idling hurts some work loads.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-06-01 10:12:26 +02:00
Jens Axboe
12e9fddd6e [PATCH] cfq-iosched: Detect idle process issuing async request
If we are anticipating a sync request from this process and we are
waiting for that and see an async request come in, expire that slice
and move on.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-06-01 10:09:56 +02:00
Jens Axboe
e0de0206a2 [PATCH] cfq-iosched: check busy queues before deciding we are idle
For just one busy queue (like async write out), we often overlooked
that we could queue more io and decided we were idle instead. This causes
us quite a bit of performance loss.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-06-01 10:07:26 +02:00
Jens Axboe
3793c65c13 [PATCH] cfq-iosched: fixup locking and ->queue_list list management
- Drop cic from the list when seen as dead.
- Fixup the locking, just use a simple spinlock.

Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-05-30 20:31:05 -07:00
David Woodhouse
3db3a44530 [RBTREE] Change rbtree off-tree marking in I/O schedulers.
They were abusing the rb_color field to mark nodes which weren't currently
on the tree. Fix that to use the same method as eventpoll did -- setting
the parent pointer to point back to itself. And use the appropriate
accessor macros for setting and reading the parent.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-04-21 13:15:17 +01:00
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