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2012-05-17cfq-iosched: fix a rcu warningShaohua Li
commit 3181faa85bda3dc3f5e630a1846526c9caaa38e3 upstream. I got a rcu warnning at boot. the ioc->ioc_data is rcu_deferenced, but doesn't hold rcu_read_lock. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-05-17cfq-iosched: fix locking around ioc->ioc_data assignmentJens Axboe
commit ab4bd22d3cce6977dc039664cc2d052e3147d662 upstream. Since we are modifying this RCU pointer, we need to hold the lock protecting it around it. This fixes a potential reuse and double free of a cfq io_context structure. The bug has been in CFQ for a long time, it hit very few people but those it did hit seemed to see it a lot. Tracked in RH bugzilla here: https://bugzilla.redhat.com/show_bug.cgi?id=577968 Credit goes to Paul Bolle for figuring out that the issue was around the one-hit ioc->ioc_data cache. Thanks to his hard work the issue is now fixed. Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-05-17block: export blk_{get,put}_queue()Jens Axboe
commit d86e0e83b32bc84600adb0b6ea1fce389b266682 upstream. We need them in SCSI to fix a bug, but currently they are not exported to modules. Export them. Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-05-17block: add proper state guards to __elv_next_requestJames Bottomley
commit 0a58e077eb600d1efd7e54ad9926a75a39d7f8ae upstream. blk_cleanup_queue() calls elevator_exit() and after this, we can't touch the elevator without oopsing. __elv_next_request() must check for this state because in the refcounted queue model, we can still call it after blk_cleanup_queue() has been called. This was reported as causing an oops attributable to scsi. Signed-off-by: James Bottomley <James.Bottomley@suse.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-03-14block, blk-sysfs: Fix an err return path in blk_register_queue()Liu Yuan
commit ed5302d3c25006a9edc7a7fbea97a30483f89ef7 upstream. We do not call blk_trace_remove_sysfs() in err return path if kobject_add() fails. This path fixes it. Signed-off-by: Liu Yuan <tailai.ly@taobao.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-04-17block: check for proper length of iov entries earlier in blk_rq_map_user_iov()Xiaotian Feng
commit 5478755616ae2ef1ce144dded589b62b2a50d575 upstream. commit 9284bcf checks for proper length of iov entries in blk_rq_map_user_iov(). But if the map is unaligned, kernel will break out the loop without checking for the proper length. So we need to check the proper length before the unalign check. Signed-off-by: Xiaotian Feng <dfeng@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-04-17block: Deprecate QUEUE_FLAG_CLUSTER and use queue_limits insteadMartin K. Petersen
commit e692cb668fdd5a712c6ed2a2d6f2a36ee83997b4 upstream. When stacking devices, a request_queue is not always available. This forced us to have a no_cluster flag in the queue_limits that could be used as a carrier until the request_queue had been set up for a metadevice. There were several problems with that approach. First of all it was up to the stacking device to remember to set queue flag after stacking had completed. Also, the queue flag and the queue limits had to be kept in sync at all times. We got that wrong, which could lead to us issuing commands that went beyond the max scatterlist limit set by the driver. The proper fix is to avoid having two flags for tracking the same thing. We deprecate QUEUE_FLAG_CLUSTER and use the queue limit directly in the block layer merging functions. The queue_limit 'no_cluster' is turned into 'cluster' to avoid double negatives and to ease stacking. Clustering defaults to being enabled as before. The queue flag logic is removed from the stacking function, and explicitly setting the cluster flag is no longer necessary in DM and MD. Reported-by: Ed Lin <ed.lin@promise.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-04-17block: check for proper length of iov entries in blk_rq_map_user_iov()Jens Axboe
commit 9284bcf4e335e5f18a8bc7b26461c33ab60d0689 upstream. Ensure that we pass down properly validated iov segments before calling into the mapping or copy functions. Reported-by: Dan Rosenberg <drosenberg@vsecurity.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-04-17block: take care not to overflow when calculating total iov lengthJens Axboe
commit 9f864c80913467312c7b8690e41fb5ebd1b50e92 upstream. Reported-by: Dan Rosenberg <drosenberg@vsecurity.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-04-17block: Ensure physical block size is unsigned intMartin K. Petersen
commit 892b6f90db81cccb723d5d92f4fddc2d68b206e1 upstream. Physical block size was declared unsigned int to accomodate the maximum size reported by READ CAPACITY(16). Make sure we use the right type in the related functions. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-01-06bsg: fix incorrect device_status valueFUJITA Tomonori
commit 478971600e47cb83ff2d3c63c5c24f2b04b0d6a1 upstream. bsg incorrectly returns sg's masked_status value for device_status. [jejb: fix up expression logic] Reported-by: Douglas Gilbert <dgilbert@interlog.com> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: James Bottomley <James.Bottomley@suse.de> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2010-08-02block: Don't count_vm_events for discard bio in submit_bio.Tao Ma
commit 1b99973f1c82707e46e8cb9416865a1e955e8f8c upstream. In submit_bio, we count vm events by check READ/WRITE. But actually DISCARD_NOBARRIER also has the WRITE flag set. It looks as if in blkdev_issue_discard, we also add a page as the payload and the bio_has_data check isn't enough. So add another check for discard bio. Signed-off-by: Tao Ma <tao.ma@oracle.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-08-02cfq: Don't allow queue merges for queues that have no process referencesJeff Moyer
commit c10b61f0910466b4b99c266a7d76ac4390743fb5 upstream. Hi, A user reported a kernel bug when running a particular program that did the following: created 32 threads - each thread took a mutex, grabbed a global offset, added a buffer size to that offset, released the lock - read from the given offset in the file - created a new thread to do the same - exited The result is that cfq's close cooperator logic would trigger, as the threads were issuing I/O within the mean seek distance of one another. This workload managed to routinely trigger a use after free bug when walking the list of merge candidates for a particular cfqq (cfqq->new_cfqq). The logic used for merging queues looks like this: static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) { int process_refs, new_process_refs; struct cfq_queue *__cfqq; /* Avoid a circular list and skip interim queue merges */ while ((__cfqq = new_cfqq->new_cfqq)) { if (__cfqq == cfqq) return; new_cfqq = __cfqq; } process_refs = cfqq_process_refs(cfqq); /* * If the process for the cfqq has gone away, there is no * sense in merging the queues. */ if (process_refs == 0) return; /* * Merge in the direction of the lesser amount of work. */ new_process_refs = cfqq_process_refs(new_cfqq); if (new_process_refs >= process_refs) { cfqq->new_cfqq = new_cfqq; atomic_add(process_refs, &new_cfqq->ref); } else { new_cfqq->new_cfqq = cfqq; atomic_add(new_process_refs, &cfqq->ref); } } When a merge candidate is found, we add the process references for the queue with less references to the queue with more. The actual merging of queues happens when a new request is issued for a given cfqq. In the case of the test program, it only does a single pread call to read in 1MB, so the actual merge never happens. Normally, this is fine, as when the queue exits, we simply drop the references we took on the other cfqqs in the merge chain: /* * If this queue was scheduled to merge with another queue, be * sure to drop the reference taken on that queue (and others in * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. */ __cfqq = cfqq->new_cfqq; while (__cfqq) { if (__cfqq == cfqq) { WARN(1, "cfqq->new_cfqq loop detected\n"); break; } next = __cfqq->new_cfqq; cfq_put_queue(__cfqq); __cfqq = next; } However, there is a hole in this logic. Consider the following (and keep in mind that each I/O keeps a reference to the cfqq): q1->new_cfqq = q2 // q2 now has 2 process references q3->new_cfqq = q2 // q2 now has 3 process references // the process associated with q2 exits // q2 now has 2 process references // queue 1 exits, drops its reference on q2 // q2 now has 1 process reference // q3 exits, so has 0 process references, and hence drops its references // to q2, which leaves q2 also with 0 process references q4 comes along and wants to merge with q3 q3->new_cfqq still points at q2! We follow that link and end up at an already freed cfqq. So, the fix is to not follow a merge chain if the top-most queue does not have a process reference, otherwise any queue in the chain could be already freed. I also changed the logic to disallow merging with a queue that does not have any process references. Previously, we did this check for one of the merge candidates, but not the other. That doesn't really make sense. Without the attached patch, my system would BUG within a couple of seconds of running the reproducer program. With the patch applied, my system ran the program for over an hour without issues. This addresses the following bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=16217 Thanks a ton to Phil Carns for providing the bug report and an excellent reproducer. [ Note for stable: this applies to 2.6.32/33/34 ]. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Reported-by: Phil Carns <carns@mcs.anl.gov> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-07-05cfq-iosched: fix an oops caused by slab leakShaohua Li
commit d02a2c077fb81f3224c770be62a318165b23b486 upstream. I got below oops when unloading cfq-iosched. Considering scenario: queue A merge to B, C merge to D and B will be merged to D. Before B is merged to D, we do split B. We should put B's reference for D. [ 807.768536] ============================================================================= [ 807.768539] BUG cfq_queue: Objects remaining on kmem_cache_close() [ 807.768541] ----------------------------------------------------------------------------- [ 807.768543] [ 807.768546] INFO: Slab 0xffffea0003e6b4e0 objects=26 used=1 fp=0xffff88011d584fd8 flags=0x200000000004082 [ 807.768550] Pid: 5946, comm: rmmod Tainted: G W 2.6.34-07097-gf4b87de-dirty #724 [ 807.768552] Call Trace: [ 807.768560] [<ffffffff81104e8d>] slab_err+0x8f/0x9d [ 807.768564] [<ffffffff811059e1>] ? flush_cpu_slab+0x0/0x93 [ 807.768569] [<ffffffff8164be52>] ? add_preempt_count+0xe/0xca [ 807.768572] [<ffffffff8164bd9c>] ? sub_preempt_count+0xe/0xb6 [ 807.768577] [<ffffffff81648871>] ? _raw_spin_unlock+0x15/0x30 [ 807.768580] [<ffffffff8164bd9c>] ? sub_preempt_count+0xe/0xb6 [ 807.768584] [<ffffffff811061bc>] list_slab_objects+0x9b/0x19f [ 807.768588] [<ffffffff8164bf0a>] ? add_preempt_count+0xc6/0xca [ 807.768591] [<ffffffff81109e27>] kmem_cache_destroy+0x13f/0x21d [ 807.768597] [<ffffffffa000ff13>] cfq_slab_kill+0x1a/0x43 [cfq_iosched] [ 807.768601] [<ffffffffa000ffcf>] cfq_exit+0x93/0x9e [cfq_iosched] [ 807.768606] [<ffffffff810973a2>] sys_delete_module+0x1b1/0x219 [ 807.768612] [<ffffffff8102fb5b>] system_call_fastpath+0x16/0x1b [ 807.768618] INFO: Object 0xffff88011d584618 @offset=1560 [ 807.768622] INFO: Allocated in cfq_get_queue+0x11e/0x274 [cfq_iosched] age=7173 cpu=1 pid=5496 [ 807.768626] ============================================================================= Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-05-07blk-cgroup: Fix an RCU warning in blkiocg_create()Li Zefan
with CONFIG_PROVE_RCU=y, a warning can be triggered: # mount -t cgroup -o blkio xxx /mnt # mkdir /mnt/subgroup ... kernel/cgroup.c:4442 invoked rcu_dereference_check() without protection! ... To fix this, we avoid caling css_depth() here, which is a bit simpler than the original code. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-05-06blk-cgroup: Fix RCU correctness warning in cfq_init_queue()Vivek Goyal
It is necessary to be in an RCU read-side critical section when invoking css_id(), so this patch adds one to blkiocg_add_blkio_group(). This is actually a false positive, because this is called at initialization time and hence always refers to the root cgroup, which cannot go away. [ 103.790505] =================================================== [ 103.790509] [ INFO: suspicious rcu_dereference_check() usage. ] [ 103.790511] --------------------------------------------------- [ 103.790514] kernel/cgroup.c:4432 invoked rcu_dereference_check() without protection! [ 103.790517] [ 103.790517] other info that might help us debug this: [ 103.790519] [ 103.790521] [ 103.790521] rcu_scheduler_active = 1, debug_locks = 1 [ 103.790524] 4 locks held by bash/4422: [ 103.790526] #0: (&buffer->mutex){+.+.+.}, at: [<ffffffff8114befa>] sysfs_write_file+0x3c/0x144 [ 103.790537] #1: (s_active#102){.+.+.+}, at: [<ffffffff8114bfa5>] sysfs_write_file+0xe7/0x144 [ 103.790544] #2: (&q->sysfs_lock){+.+.+.}, at: [<ffffffff812263b1>] queue_attr_store+0x49/0x8f [ 103.790552] #3: (&(&blkcg->lock)->rlock){......}, at: [<ffffffff8122e4db>] blkiocg_add_blkio_group+0x2b/0xad [ 103.790560] [ 103.790561] stack backtrace: [ 103.790564] Pid: 4422, comm: bash Not tainted 2.6.34-rc4-blkio-second-crash #81 [ 103.790567] Call Trace: [ 103.790572] [<ffffffff81068f57>] lockdep_rcu_dereference+0x9d/0xa5 [ 103.790577] [<ffffffff8107fac1>] css_id+0x44/0x57 [ 103.790581] [<ffffffff8122e503>] blkiocg_add_blkio_group+0x53/0xad [ 103.790586] [<ffffffff81231936>] cfq_init_queue+0x139/0x32c [ 103.790591] [<ffffffff8121f2d0>] elv_iosched_store+0xbf/0x1bf [ 103.790595] [<ffffffff812263d8>] queue_attr_store+0x70/0x8f [ 103.790599] [<ffffffff8114bfa5>] ? sysfs_write_file+0xe7/0x144 [ 103.790603] [<ffffffff8114bfc6>] sysfs_write_file+0x108/0x144 [ 103.790609] [<ffffffff810f527f>] vfs_write+0xae/0x10b [ 103.790612] [<ffffffff81069863>] ? trace_hardirqs_on_caller+0x10c/0x130 [ 103.790616] [<ffffffff810f539c>] sys_write+0x4a/0x6e [ 103.790622] [<ffffffff81002b5b>] system_call_fastpath+0x16/0x1b [ 103.790625] Located-by: Miles Lane <miles.lane@gmail.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-04-21block: ensure jiffies wrap is handled correctly in blk_rq_timed_out_timerRichard Kennedy
blk_rq_timed_out_timer() relied on blk_add_timer() never returning a timer value of zero, but commit 7838c15b8dd18e78a523513749e5b54bda07b0cb removed the code that bumped this value when it was zero. Therefore when jiffies is near wrap we could get unlucky & not set the timeout value correctly. This patch uses a flag to indicate that the timeout value was set and so handles jiffies wrap correctly, and it keeps all the logic in one function so should be easier to maintain in the future. Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk> Cc: stable@kernel.org Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-04-09Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-linus' of git://git.kernel.dk/linux-2.6-block: (34 commits) cfq-iosched: Fix the incorrect timeslice accounting with forced_dispatch loop: Update mtime when writing using aops block: expose the statistics in blkio.time and blkio.sectors for the root cgroup backing-dev: Handle class_create() failure Block: Fix block/elevator.c elevator_get() off-by-one error drbd: lc_element_by_index() never returns NULL cciss: unlock on error path cfq-iosched: Do not merge queues of BE and IDLE classes cfq-iosched: Add additional blktrace log messages in CFQ for easier debugging i2o: Remove the dangerous kobj_to_i2o_device macro block: remove 16 bytes of padding from struct request on 64bits cfq-iosched: fix a kbuild regression block: make CONFIG_BLK_CGROUP visible Remove GENHD_FL_DRIVERFS block: Export max number of segments and max segment size in sysfs block: Finalize conversion of block limits functions block: Fix overrun in lcm() and move it to lib vfs: improve writeback_inodes_wb() paride: fix off-by-one test drbd: fix al-to-on-disk-bitmap for 4k logical_block_size ...
2010-04-09cfq-iosched: Fix the incorrect timeslice accounting with forced_dispatchDivyesh Shah
When CFQ dispatches requests forcefully due to a barrier or changing iosched, it runs through all cfqq's dispatching requests and then expires each queue. However, it does not activate a cfqq before flushing its IOs resulting in using stale values for computing slice_used. This patch fixes it by calling activate queue before flushing reuqests from each queue. This is useful mostly for barrier requests because when the iosched is changing it really doesnt matter if we have incorrect accounting since we're going to break down all structures anyway. We also now expire the current timeslice before moving on with the dispatch to accurately account slice used for that cfqq. Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-04-05block: expose the statistics in blkio.time and blkio.sectors for the root cgroupRicky Benitez
Currently, the io statistics for the root cgroup are maintained, but they are not shown because the device information is not available at the point that the root blkio cgroup is created. This patch updates the device information when the statistics are updated so that the statistics become visible. Signed-off-by: Ricky Benitez <rickyb@google.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-04-02Block: Fix block/elevator.c elevator_get() off-by-one errorwzt.wzt@gmail.com
elevator_get() not check the name length, if the name length > sizeof(elv), elv will miss the '\0'. And elv buffer will be replace "-iosched" as something like aaaaaaaaa, then call request_module() can load an not trust module. Signed-off-by: Zhitong Wang <zhitong.wangzt@alibaba-inc.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-25cfq-iosched: Do not merge queues of BE and IDLE classesDivyesh Shah
Even if they are found to be co-operating. The prio_trees do not have any IDLE cfqqs on them. cfq_close_cooperator() is called from cfq_select_queue() and cfq_completed_request(). The latter ensures that the close cooperator code does not get invoked if the current cfqq is of class IDLE but the former doesn't seem to have any such checks. So an IDLE cfqq may get merged with a BE cfqq from the same group which should be avoided. Signed-off-by: Divyesh Shah<dpshah@google.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-25cfq-iosched: Add additional blktrace log messages in CFQ for easier debuggingDivyesh Shah
These have helped us debug some issues we've noticed in earlier IO controller versions and should be useful now as well. The extra logging covers: - idling behavior. Since there are so many conditions based on which we decide to idle or not, this patch adds a log message for some conditions that we've found useful. - workload slices and current prio and workload type Changelog from v1: o moved log message from cfq_set_active_queue() to __cfq_set_active_queue() o changed queue_count to st->count Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-19Merge branch 'master' into for-linusJens Axboe
Conflicts: block/Kconfig Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-19cfq-iosched: fix a kbuild regressionShaohua Li
Alex Shi reported a kbuild regression which is about 10% performance lost. He bisected to this commit: 3dde36ddea3e07dd025c4c1ba47edec91606fec0. The reason is cfqq_close() can't find close cooperator. Restoring cfq_rq_close()'s threshold to original value makes the regression go away. Since for_preempt parameter isn't used anymore, this patch deletes it. Reported-by: Alex Shi <alex.shi@intel.com> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Acked-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-16block: make CONFIG_BLK_CGROUP visibleLi Zefan
Make the config visible, so we can choose from CONFIG_BLK_CGROUP=y and CONFIG_BLK_CGROUP=m when CONFIG_IOSCHED_CFQ=m. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-15block: Export max number of segments and max segment size in sysfsMartin K. Petersen
These two values are useful when debugging issues surrounding maximum I/O size. Put them in sysfs with the rest of the queue limits. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-15block: Fix overrun in lcm() and move it to libMartin K. Petersen
lcm() was defined to take integer-sized arguments. The supplied arguments are multiplied, however, causing us to overflow given sufficiently large input. That in turn led to incorrect optimal I/O size reporting in some cases (RAID over RAID). Switch lcm() over to unsigned long similar to gcd() and move the function from blk-settings.c to lib. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-12Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (56 commits) doc: fix typo in comment explaining rb_tree usage Remove fs/ntfs/ChangeLog doc: fix console doc typo doc: cpuset: Update the cpuset flag file Fix of spelling in arch/sparc/kernel/leon_kernel.c no longer needed Remove drivers/parport/ChangeLog Remove drivers/char/ChangeLog doc: typo - Table 1-2 should refer to "status", not "statm" tree-wide: fix typos "ass?o[sc]iac?te" -> "associate" in comments No need to patch AMD-provided drivers/gpu/drm/radeon/atombios.h devres/irq: Fix devm_irq_match comment Remove reference to kthread_create_on_cpu tree-wide: Assorted spelling fixes tree-wide: fix 'lenght' typo in comments and code drm/kms: fix spelling in error message doc: capitalization and other minor fixes in pnp doc devres: typo fix s/dev/devm/ Remove redundant trailing semicolons from macros fix typo "definetly" -> "definitely" in comment tree-wide: s/widht/width/g typo in comments ... Fix trivial conflict in Documentation/laptops/00-INDEX
2010-03-12cgroups: blkio subsystem as moduleBen Blum
Modify the Block I/O cgroup subsystem to be able to be built as a module. As the CFQ disk scheduler optionally depends on blk-cgroup, config options in block/Kconfig, block/Kconfig.iosched, and block/blk-cgroup.h are enhanced to support the new module dependency. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.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>
2010-03-08Merge branch 'for-next' into for-linusJiri Kosina
Conflicts: Documentation/filesystems/proc.txt arch/arm/mach-u300/include/mach/debug-macro.S drivers/net/qlge/qlge_ethtool.c drivers/net/qlge/qlge_main.c drivers/net/typhoon.c
2010-03-07Driver core: Constify struct sysfs_ops in struct kobj_typeEmese Revfy
Constify struct sysfs_ops. This is part of the ops structure constification effort started by Arjan van de Ven et al. Benefits of this constification: * prevents modification of data that is shared (referenced) by many other structure instances at runtime * detects/prevents accidental (but not intentional) modification attempts on archs that enforce read-only kernel data at runtime * potentially better optimized code as the compiler can assume that the const data cannot be changed * the compiler/linker move const data into .rodata and therefore exclude them from false sharing Signed-off-by: Emese Revfy <re.emese@gmail.com> Acked-by: David Teigland <teigland@redhat.com> Acked-by: Matt Domsch <Matt_Domsch@dell.com> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Acked-by: Hans J. Koch <hjk@linutronix.de> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: Jens Axboe <jens.axboe@oracle.com> Acked-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-03-01block: don't access jiffies when initialising io_contextRichard Kennedy
As the comment says the initial value of last_waited is never used, so there is no need to initialise it with the current jiffies. Jiffies is hot enough without accessing it for no reason. Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-01cfq: remove 8 bytes of padding from cfq_rb_root on 64 bit buildsRichard Kennedy
Reorder cfq_rb_root to remove 8 bytes of padding on 64 bit builds. Consequently removing 56 bytes from cfq_group and 64 bytes from cfq_data. Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-01cfq-iosched: quantum check tweakShaohua Li
Currently a queue can only dispatch up to 4 requests if there are other queues. This isn't optimal, device can handle more requests, for example, AHCI can handle 31 requests. I can understand the limit is for fairness, but we could do a tweak: if the queue still has a lot of slice left, sounds we could ignore the limit. Test shows this boost my workload (two thread randread of a SSD) from 78m/s to 100m/s. Thanks for suggestions from Corrado and Vivek for the patch. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-28cfq-iosched: requests "in flight" vs "in driver" clarificationCorrado Zoccolo
Counters for requests "in flight" and "in driver" are used asymmetrically in cfq_may_dispatch, and have slightly different meaning. We split the rq_in_flight counter (was sync_flight) to count both sync and async requests, in order to use this one, which is more accurate in some corner cases. The rq_in_driver counter is coalesced, since individual sync/async counts are not used any more. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-28cfq-iosched: rethink seeky detection for SSDsCorrado Zoccolo
CFQ currently applies the same logic of detecting seeky queues and grouping them together for rotational disks as well as SSDs. For SSDs, the time to complete a request doesn't depend on the request location, but only on the size. This patch therefore changes the criterion to group queues by request size in case of SSDs, in order to achieve better fairness. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-28cfq-iosched: rework seeky detectionCorrado Zoccolo
Current seeky detection is based on average seek lenght. This is suboptimal, since the average will not distinguish between: * a process doing medium sized seeks * a process doing some sequential requests interleaved with larger seeks and even a medium seek can take lot of time, if the requested sector happens to be behind the disk head in the rotation (50% probability). Therefore, we change the seeky queue detection to work as follows: * each request can be classified as sequential if it is very close to the current head position, i.e. it is likely in the disk cache (disks usually read more data than requested, and put it in cache for subsequent reads). Otherwise, the request is classified as seeky. * an history window of the last 32 requests is kept, storing the classification result. * A queue is marked as seeky if more than 1/8 of the last 32 requests were seeky. This patch fixes a regression reported by Yanmin, on mmap 64k random reads. Reported-by: Yanmin Zhang <yanmin_zhang@linux.intel.com> Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26block: Consolidate phys_segment and hw_segment limitsMartin K. Petersen
Except for SCSI no device drivers distinguish between physical and hardware segment limits. Consolidate the two into a single segment limit. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26block: Rename blk_queue_max_sectors to blk_queue_max_hw_sectorsMartin K. Petersen
The block layer calling convention is blk_queue_<limit name>. blk_queue_max_sectors predates this practice, leading to some confusion. Rename the function to appropriately reflect that its intended use is to set max_hw_sectors. Also introduce a temporary wrapper for backwards compability. This can be removed after the merge window is closed. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26block: Add BLK_ prefix to definitionsMartin K. Petersen
Add a BLK_ prefix to block layer constants. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26block: Remove unused accessor functionMartin K. Petersen
blk_queue_max_hw_sectors is no longer called by any subsystem and can be removed. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26block: Update blk_queue_max_sectors and documentationMartin K. Petersen
Clarify blk_queue_max_sectors and update documentation. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26cfq: Remove useless css reference getGui Jianfeng
There's no need to take css reference here, for the caller has already called rcu_read_lock() to prevent cgroup from being removed. Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-25Merge branch 'master' into for-2.6.34Jens Axboe
Conflicts: include/linux/blkdev.h Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-23blk-core: use BIO list management functionsAkinobu Mita
Now that the bio list management stuff is generic, convert generic_make_request to use bio lists instead of its own private bio list implementation. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-23Revert "block: improve queue_should_plug() by looking at IO depths"Jens Axboe
This reverts commit fb1e75389bd06fd5987e9cda1b4e0305c782f854. "Benjamin S." <sbenni@gmx.de> reports that the patch in question causes a big drop in sequential throughput for him, dropping from 200MB/sec down to only 70MB/sec. Needs to be investigated more fully, for now lets just revert the offending commit. Conflicts: include/linux/blkdev.h Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-22cfq: reorder cfq_queue removing padding on 64bitRichard Kennedy
This removes 8 bytes of padding from struct cfq_queue on 64 bit builds, shrinking it's size to 256 bytes, so fitting into 1 fewer cachelines and allowing 1 more object/slab in it's kmem_cache. Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> ---- patch against 2.6.33-rc8 tested on x86_64 AMDX2 Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-22Merge branch 'master' into for-2.6.34Jens Axboe