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2009-04-07block: fix inconsistency in I/O stat accounting codeJerome Marchand
This forces in_flight to be zero when turning off or on the I/O stat accounting and stops updating I/O stats in attempt_merge() when accounting is turned off. Signed-off-by: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-07block: elevator quiescing helpersJens Axboe
Simple helper functions to quiesce the request queue. These are currently only used for switching IO schedulers on-the-fly, but we can use them to properly switch IO accounting on and off as well. Signed-off-by: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-06block: change the request allocation/congestion logic to be sync/async basedJens Axboe
This makes sure that we never wait on async IO for sync requests, instead of doing the split on writes vs reads. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-29block: get rid of elevator_t typedefJens Axboe
Just use struct elevator_queue everywhere instead. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29block: simplify empty barrier implementationTejun Heo
Empty barrier required special handling in __elv_next_request() to complete it without letting the low level driver see it. With previous changes, barrier code is now flexible enough to skip the BAR step using the same barrier sequence selection mechanism. Drop the special handling and mask off q->ordered from start_ordered(). Remove blk_empty_barrier() test which now has no user. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29block: make barrier completion more robustTejun Heo
Barrier completion had the following assumptions. * start_ordered() couldn't finish the whole sequence properly. If all actions are to be skipped, q->ordseq is set correctly but the actual completion was never triggered thus hanging the barrier request. * Drain completion in elv_complete_request() assumed that there's always at least one request in the queue when drain completes. Both assumptions are true but these assumptions need to be removed to improve empty barrier implementation. This patch makes the following changes. * Make start_ordered() use blk_ordered_complete_seq() to mark skipped steps complete and notify __elv_next_request() that it should fetch the next request if the whole barrier has completed inside start_ordered(). * Make drain completion path in elv_complete_request() check whether the queue is empty. Empty queue also indicates drain completion. * While at it, convert 0/1 return from blk_do_ordered() to false/true. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-05Merge branches 'tracing/ftrace', 'tracing/function-graph-tracer' and ↵Ingo Molnar
'tracing/urgent' into tracing/core
2008-12-03block: internal dequeue shouldn't start timerTejun Heo
blkdev_dequeue_request() and elv_dequeue_request() are equivalent and both start the timeout timer. Barrier code dequeues the original barrier request but doesn't passes the request itself to lower level driver, only broken down proxy requests; however, as the original barrier code goes through the same dequeue path and timeout timer is started on it. If barrier sequence takes long enough, this timer expires but the low level driver has no idea about this request and oops follows. Timeout timer shouldn't have been started on the original barrier request as it never goes through actual IO. This patch unexports elv_dequeue_request(), which has no external user anyway, and makes it operate on elevator proper w/o adding the timer and make blkdev_dequeue_request() call elv_dequeue_request() and add timer. Internal users which don't pass the request to driver - barrier code and end_that_request_last() - are converted to use elv_dequeue_request(). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-11-26blktrace: port to tracepoints, updateIngo Molnar
Port to the new tracepoints API: split DEFINE_TRACE() and DECLARE_TRACE() sites. Spread them out to the usage sites, as suggested by Mathieu Desnoyers. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
2008-11-26blktrace: port to tracepointsArnaldo Carvalho de Melo
This was a forward port of work done by Mathieu Desnoyers, I changed it to encode the 'what' parameter on the tracepoint name, so that one can register interest in specific events and not on classes of events to then check the 'what' parameter. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-06block: add timer on blkdev_dequeue_request() not elv_next_request()Tejun Heo
Block queue supports two usage models - one where block driver peeks at the front of queue using elv_next_request(), processes it and finishes it and the other where block driver peeks at the front of queue, dequeue the request using blkdev_dequeue_request() and finishes it. The latter is more flexible as it allows the driver to process multiple commands concurrently. These two inconsistent usage models affect the block layer implementation confusing. For some, elv_next_request() is considered the issue point while others consider blkdev_dequeue_request() the issue point. Till now the inconsistency mostly affect only accounting, so it didn't really break anything seriously; however, with block layer timeout, this inconsistency hits hard. Block layer considers elv_next_request() the issue point and adds timer but SCSI layer thinks it was just peeking and when the request can't process the command right away, it's just left there without further processing. This makes the request dangling on the timer list and, when the timer goes off, the request which the SCSI layer and below think is still on the block queue ends up in the EH queue, causing various problems - EH hang (failed count goes over busy count and EH never wakes up), WARN_ON() and oopses as low level driver trying to handle the unknown command, etc. depending on the timing. As SCSI midlayer is the only user of block layer timer at the moment, moving blk_add_timer() to elv_dequeue_request() fixes the problem; however, this two usage models definitely need to be cleaned up in the future. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-17block: only call ->request_fn when the queue is not stoppedJens Axboe
Callers should use either blk_run_queue/__blk_run_queue, or blk_start_queueing() to invoke request handling instead of calling ->request_fn() directly as that does not take the queue stopped flag into account. Also add appropriate comments on the above functions to detail their usage. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-17block: simplify string handling in elv_iosched_store()Li Zefan
strlcpy() guarantees the dest buffer is NULL teminated. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: change elevator to use __blk_end_request()Kiyoshi Ueda
This patch converts elevator to use __blk_end_request() directly so that end_{queued|dequeued}_request() can be removed. Related 'uptodate' arguments is converted to 'error'. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: Add interface to abort queued requestsMike Anderson
Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: unify request timeout handlingJens Axboe
Right now SCSI and others do their own command timeout handling. Move those bits to the block layer. Instead of having a timer per command, we try to be a bit more clever and simply have one per-queue. This avoids the overhead of having to tear down and setup a timer for each command, so it will result in a lot less timer fiddling. Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: use linux/uaccess.h in elevator.c instead of asm variantJens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09drop vmerge accountingMikulas Patocka
Remove hw_segments field from struct bio and struct request. Without virtual merge accounting they have no purpose. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09Allow elevators to sort/merge discard requestsDavid Woodhouse
But blkdev_issue_discard() still emits requests which are interpreted as soft barriers, because naïve callers might otherwise issue subsequent writes to those same sectors, which might cross on the queue (if they're reallocated quickly enough). Callers still _can_ issue non-barrier discard requests, but they have to take care of queue ordering for themselves. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-03block: request_module(): use format stringmaximilian attems
Avoid bad things happening if the module has a printk control string in its name. Signed-off-by: maximilian attems <max@stro.at> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-03block: Block layer data integrity supportMartin K. Petersen
Some block devices support verifying the integrity of requests by way of checksums or other protection information that is submitted along with the I/O. This patch implements support for generating and verifying integrity metadata, as well as correctly merging, splitting and cloning bios and requests that have this extra information attached. See Documentation/block/data-integrity.txt for more information. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-05-28Added in elevator switch message to blktrace streamAlan D. Brunelle
Signed-off-by: Alan D. Brunelle <alan.brunelle@hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-05-01block: remove remaining __FUNCTION__ occurrencesHarvey Harrison
__FUNCTION__ is gcc specific, use __func__ Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29block: Skip I/O merges when disabledAlan D. Brunelle
The block I/O + elevator + I/O scheduler code spend a lot of time trying to merge I/Os -- rightfully so under "normal" circumstances. However, if one were to know that the incoming I/O stream was /very/ random in nature, the cycles are wasted. This patch adds a per-request_queue tunable that (when set) disables merge attempts (beyond the simple one-hit cache check), thus freeing up a non-trivial amount of CPU cycles. Signed-off-by: Alan D. Brunelle <alan.brunelle@hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-04-29block/elevator.c:elv_rq_merge_ok() mustn't be inlineAdrian Bunk
This patch fixes the following build error with UML and gcc 4.3: <-- snip --> ... CC block/elevator.o /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c: In function ‘elv_merge’: /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c:73: sorry, unimplemented: inlining failed in call to ‘elv_rq_merge_ok’: function body not available /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c:103: sorry, unimplemented: called from here /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c:73: sorry, unimplemented: inlining failed in call to ‘elv_rq_merge_ok’: function body not available /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c:495: sorry, unimplemented: called from here make[2]: *** [block/elevator.o] Error 1 make[1]: *** [block] Error 2 <-- snip --> Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-04-29block: make queue flags non-atomicNick Piggin
We can save some atomic ops in the IO path, if we clearly define the rules of how to modify the queue flags. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-02-19elevator: make elevator_get() attempt to load the appropriate moduleJens Axboe
Currently we fail if someone requests a valid io scheduler, but it's modular and not currently loaded. That can happen from a driver init asking for a different scheduler, or online switching through sysfs as requested by a user. This patch makes elevator_get() request_module() to attempt to load the appropriate module, instead of requiring that done manually. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-02-01block: make elevator lib checkpatch compliantJens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-01-28block: implement drain buffersJames Bottomley
These DMA drain buffer implementations in drivers are pretty horrible to do in terms of manipulating the scatterlist. Plus they're being done at least in drivers/ide and drivers/ata, so we now have code duplication. The one use case for this, as I understand it is AHCI controllers doing PIO mode to mmc devices but translating this to DMA at the controller level. So, what about adding a callback to the block layer that permits the adding of the drain buffer for the problem devices. The idea is that you'd do this in slave_configure after you find one of these devices. The beauty of doing it in the block layer is that it quietly adds the drain buffer to the end of the sg list, so it automatically gets mapped (and unmapped) without anything unusual having to be done to the scatterlist in driver/scsi or drivers/ata and without any alteration to the transfer length. Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-01-24Kobject: rename kobject_init_ng() to kobject_init()Greg Kroah-Hartman
Now that the old kobject_init() function is gone, rename kobject_init_ng() to kobject_init() to clean up the namespace. Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24Kobject: rename kobject_add_ng() to kobject_add()Greg Kroah-Hartman
Now that the old kobject_add() function is gone, rename kobject_add_ng() to kobject_add() to clean up the namespace. Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24Kobject: convert block/elevator.c to use kobject_init/add_ng()Greg Kroah-Hartman
This converts the code to use the new kobject functions, cleaning up the logic in doing so. Cc: Jens Axboe <axboe@kernel.dk> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-12-18block: let elv_register() return voidAdrian Bunk
elv_register() always returns 0, and there isn't anything it does where it should return an error (the only error condition is so grave that it's handled with a BUG_ON). Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-20fix typo "insted" -> "instead"Uwe Kleine-König
Signed-off-by: Uwe Kleine-König <ukleinek@informatik.uni-freiburg.de> Signed-off-by: Adrian Bunk <bunk@kernel.org>
2007-10-16block: Initial support for data-less (or empty) barrier supportJens Axboe
This implements functionality to pass down or insert a barrier in a queue, without having data attached to it. The ->prepare_flush_fn() infrastructure from data barriers are reused to provide this functionality. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-16block: add end_queued_request() and end_dequeued_request() helpersJens Axboe
We can use this helper in the elevator core for BLKPREP_KILL, and it'll also be useful for the empty barrier patch. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-12kobjects: fix up improper use of the kobject name fieldGreg Kroah-Hartman
A number of different drivers incorrect access the kobject name field directly. This is not correct as the name might not be in the array. Use the proper accessor function instead.
2007-07-24[BLOCK] Get rid of request_queue_t typedefJens Axboe
Some of the code has been gradually transitioned to using the proper struct request_queue, but there's lots left. So do a full sweet of the kernel and get rid of this typedef and replace its uses with the proper type. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-07-17Slab allocators: Replace explicit zeroing with __GFP_ZEROChristoph Lameter
kmalloc_node() and kmem_cache_alloc_node() were not available in a zeroing variant in the past. But with __GFP_ZERO it is possible now to do zeroing while allocating. Use __GFP_ZERO to remove the explicit clearing of memory via memset whereever we can. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-10Use list_for_each_entry() instead of list_for_each() in the block deviceMatthias Kaehlcke
elevator Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30[PATCH] elevator: elv_list_lock does not need irq disablingJens Axboe
It's never grabbed from irq context, so just make it plain spin_lock(). Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-03-27make elv_register() output atomicThibaut VARENE
Booting 2.6.21-rc3-g45592145 I noticed the following on one of my machines in the bootlog: io scheduler noop registered<6>Time: jiffies clocksource has been installed. io scheduler deadline registered (default) Looking at block/elevator.c, it appears that elv_register() uses two consecutive printks in a non-atomic way, leading to the above glitch. The attached trivial patch fixes this issue, by using a single printk. Signed-off-by: Thibaut VARENE <varenet@parisc-linux.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-02-11elevator: don't sort reads between writesJens Axboe
Don't allow elv_dispatch_sort() to mix reads and writes together, it's rarely a good idea. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-02-11elevator: abstract out the activate and deactivate functionsJens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-01-23[PATCH] elevator: move clearing of unplug flag earlierLinas Vepstas
A flag was recently added to the elevator code to avoid performing an unplug when reuests are being re-queued. The goal of this flag was to avoid a deep recursion that can occur when re-queueing requests after a SCSI device/host reset. See http://lkml.org/lkml/2006/5/17/254 However, that fix added the flag near the bottom of a case statement, where an earlier break (in an if statement) could transport one out of the case, without setting the flag. This patch sets the flag earlier in the case statement. I re-discovered the deep recursion recently during testing; I was told that it was a known problem, and the fix to it was in the kernel I was testing. Indeed it was ... but it didn't fix the bug. With the patch below, I no longer see the bug. Signed-off by: Linas Vepstas <linas@austin.ibm.com> Signed-off-by: Jens Axboe <axboe@suse.de> Cc: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-12-21[PATCH] elevator: fixup typo in merge logicJens Axboe
The recent io scheduler allow_merge commit left the block layer with no merging, oops. This patch fixes that up. That means the CFQ change needs to be verified again, it might not fix the original bug now. But that's a seperate thing, I'll double check that tomorrow. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-20[PATCH] cfq-iosched: don't allow sync merges across queuesJens Axboe
Currently we allow any merge, even if the io originates from different processes. This can cause really bad starvation and unfairness, if those ios happen to be synchronous (reads or direct writes). So add a allow_merge hook to the io scheduler ops, so an io scheduler can help decide whether a bio/process combination may be merged with an existing request. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2006-12-01[BLOCK] Cleanup unused variable passingJens Axboe
- ->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>
2006-10-12[PATCH] block layer: elv_iosched_show should get elv_list_lockVasily Tarasov
elv_iosched_show function iterates other elv_list, hence elv_list_lock should be got. Signed-off-by: Vasily Tarasov <vtaras@openvz.org> Signed-off-by: Vasily Tarasov <jens.axboe@oracle.com>
2006-10-12[PATCH] block layer: elevator_find function cleanupVasily Tarasov
We can easily produce search through the elevator list without introducing additional elevator_type variable. Signed-off-by: Vasily Tarasov <vtaras@openvz.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>