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2006-06-14[PATCH] cfq-iosched: fix crash in do_div()Jens Axboe1-8/+3
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>
2006-06-08[PATCH] elevator switching raceJens Axboe1-6/+4
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>
2006-06-01[PATCH] cfq-iosched: busy_rr fairness fixJens Axboe1-2/+5
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[PATCH] cfq-iosched: fix bug in timer handling for the idle classJens Axboe1-4/+3
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[PATCH] cfq-iosched: Detect hardware queueingJens Axboe1-2/+13
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[PATCH] cfq-iosched: Detect idle process issuing async requestJens Axboe1-3/+13
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[PATCH] cfq-iosched: check busy queues before deciding we are idleJens Axboe1-0/+7
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>
2006-05-30[PATCH] cfq-iosched: fixup locking and ->queue_list list managementJens Axboe1-12/+13
- 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>
2006-04-18[PATCH] cfq: Further rbtree traversal and cfq_exit_queue() race fixOGAWA Hirofumi1-7/+12
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[PATCH 2/2] cfq: fix cic's rbtree traversalOGAWA Hirofumi1-6/+27
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[PATCH 1/2] iosched: fix typo and barrier()OGAWA Hirofumi1-2/+3
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>
2006-03-28[BLOCK] cfq-iosched: seek and async performance fixesJens Axboe1-37/+65
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[PATCH] cfq-iosched: small cfq_choose_req() optimizationAndreas Mohr1-18/+32
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[PATCH] [BLOCK] cfq-iosched: change cfq io context linking from list to treeJens Axboe1-110/+95
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>
2006-03-26[PATCH] mempool: use mempool_create_slab_pool()Matthew Dobson1-1/+1
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>
2006-03-18[PATCH] fix rmmod problems with elevator attributes, clean them upAl Viro1-73/+20
2006-03-18[PATCH] elevator_t lifetime rules and sysfs fixesAl Viro1-57/+17
2006-03-18[PATCH] noise removal: cfq-iosched.cAl Viro1-14/+2
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18[PATCH] don't bother with refcounting for cfq_dataAl Viro1-21/+7
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18[PATCH] fix cfq_get_queue()/ioprio_set(2) racesAl Viro1-4/+12
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18[PATCH] deal with rmmod/put_io_context() racesAl Viro1-0/+16
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18[PATCH] stop elv_unregister() from rogering other iosched's data, fix lockingAl Viro1-0/+8
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18[PATCH] stop cfq from pinning queue downAl Viro1-4/+0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18[PATCH] make cfq_exit_queue() prune the cfq_io_context for that queueAl Viro1-1/+58
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18[PATCH] fix the exclusion for ioprio_set()Al Viro1-1/+13
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18[PATCH] keep sync and async cfq_queue separateAl Viro1-10/+26
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18[PATCH] switch to use of ->key to get cfq_data by cfq_io_contextAl Viro1-11/+15
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18[PATCH] stop leaking cfq_data in cfq_set_request()Al Viro1-2/+0
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[PATCH] fix cfq hash lookupsAl Viro1-1/+1
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>
2006-02-28[PATCH] cfq-iosched: slice expiry fixupsJens Axboe1-91/+60
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>
2006-01-06[BLOCK] mark some block/ variables consArjan van de Ven1-8/+8
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>
2005-11-18[BLOCK] new block/ directory comment tidyCoywolf Qi Hunt1-2/+0
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>
2005-11-12[BLOCK] cfq-iosched: fix slice_left calculationTejun Heo1-2/+2
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[BLOCK] cfq-iosched: cfq forced dispatching fixTejun Heo1-9/+45
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>
2005-11-04[BLOCK] Move all core block layer code to new block/ directoryJens Axboe1-0/+2428
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>
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