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* Merge branch 'for-3.3/core' of git://git.kernel.dk/linux-blockLinus Torvalds2012-01-15
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-3.3/core' of git://git.kernel.dk/linux-block: (37 commits) Revert "block: recursive merge requests" block: Stop using macro stubs for the bio data integrity calls blockdev: convert some macros to static inlines fs: remove unneeded plug in mpage_readpages() block: Add BLKROTATIONAL ioctl block: Introduce blk_set_stacking_limits function block: remove WARN_ON_ONCE() in exit_io_context() block: an exiting task should be allowed to create io_context block: ioc_cgroup_changed() needs to be exported block: recursive merge requests block, cfq: fix empty queue crash caused by request merge block, cfq: move icq creation and rq->elv.icq association to block core block, cfq: restructure io_cq creation path for io_context interface cleanup block, cfq: move io_cq exit/release to blk-ioc.c block, cfq: move icq cache management to block core block, cfq: move io_cq lookup to blk-ioc.c block, cfq: move cfqd->icq_list to request_queue and add request->elv.icq block, cfq: reorganize cfq_io_context into generic and cfq specific parts block: remove elevator_queue->ops block: reorder elevator switch sequence ... Fix up conflicts in: - block/blk-cgroup.c Switch from can_attach_task to can_attach - block/cfq-iosched.c conflict with now removed cic index changes (we now use q->id instead)
| * blockdev: convert some macros to static inlinesStephen Rothwell2012-01-12
| | | | | | | | | | | | | | | | | | | | | | We prefer to program in C rather than preprocessor and it fixes this warning when CONFIG_BLK_DEV_INTEGRITY is not set: drivers/md/dm-table.c: In function 'dm_table_set_integrity': drivers/md/dm-table.c:1285:3: warning: statement with no effect [-Wunused-value] Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: Introduce blk_set_stacking_limits functionMartin K. Petersen2012-01-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Stacking driver queue limits are typically bounded exclusively by the capabilities of the low level devices, not by the stacking driver itself. This patch introduces blk_set_stacking_limits() which has more liberal metrics than the default queue limits function. This allows us to inherit topology parameters from bottom devices without manually tweaking the default limits in each driver prior to calling the stacking function. Since there is now a clear distinction between stacking and low-level devices, blk_set_default_limits() has been modified to carry the more conservative values that we used to manually set in blk_queue_make_request(). Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block, cfq: move cfqd->icq_list to request_queue and add request->elv.icqTejun Heo2011-12-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most of icq management is about to be moved out of cfq into blk-ioc. This patch prepares for it. * Move cfqd->icq_list to request_queue->icq_list * Make request explicitly point to icq instead of through elevator private data. ->elevator_private[3] is replaced with sub struct elv which contains icq pointer and priv[2]. cfq is updated accordingly. * Meaningless clearing of ->elevator_private[0] removed from elv_set_request(). At that point in code, the field was guaranteed to be %NULL anyway. This patch doesn't introduce any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block, cfq: unlink cfq_io_context's immediatelyTejun Heo2011-12-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cic is association between io_context and request_queue. A cic is linked from both ioc and q and should be destroyed when either one goes away. As ioc and q both have their own locks, locking becomes a bit complex - both orders work for removal from one but not from the other. Currently, cfq tries to circumvent this locking order issue with RCU. ioc->lock nests inside queue_lock but the radix tree and cic's are also protected by RCU allowing either side to walk their lists without grabbing lock. This rather unconventional use of RCU quickly devolves into extremely fragile convolution. e.g. The following is from cfqd going away too soon after ioc and q exits raced. general protection fault: 0000 [#1] PREEMPT SMP CPU 2 Modules linked in: [ 88.503444] Pid: 599, comm: hexdump Not tainted 3.1.0-rc10-work+ #158 Bochs Bochs RIP: 0010:[<ffffffff81397628>] [<ffffffff81397628>] cfq_exit_single_io_context+0x58/0xf0 ... Call Trace: [<ffffffff81395a4a>] call_for_each_cic+0x5a/0x90 [<ffffffff81395ab5>] cfq_exit_io_context+0x15/0x20 [<ffffffff81389130>] exit_io_context+0x100/0x140 [<ffffffff81098a29>] do_exit+0x579/0x850 [<ffffffff81098d5b>] do_group_exit+0x5b/0xd0 [<ffffffff81098de7>] sys_exit_group+0x17/0x20 [<ffffffff81b02f2b>] system_call_fastpath+0x16/0x1b The only real hot path here is cic lookup during request initialization and avoiding extra locking requires very confined use of RCU. This patch makes cic removal from both ioc and request_queue perform double-locking and unlink immediately. * From q side, the change is almost trivial as ioc->lock nests inside queue_lock. It just needs to grab each ioc->lock as it walks cic_list and unlink it. * From ioc side, it's a bit more difficult because of inversed lock order. ioc needs its lock to walk its cic_list but can't grab the matching queue_lock and needs to perform unlock-relock dancing. Unlinking is now wholly done from put_io_context() and fast path is optimized by using the queue_lock the caller already holds, which is by far the most common case. If the ioc accessed multiple devices, it tries with trylock. In unlikely cases of fast path failure, it falls back to full double-locking dance from workqueue. Double-locking isn't the prettiest thing in the world but it's *far* simpler and more understandable than RCU trick without adding any meaningful overhead. This still leaves a lot of now unnecessary RCU logics. Future patches will trim them. -v2: Vivek pointed out that cic->q was being dereferenced after cic->release() was called. Updated to use local variable @this_q instead. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: misc updates to blk_get_queue()Tejun Heo2011-12-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * blk_get_queue() is peculiar in that it returns 0 on success and 1 on failure instead of 0 / -errno or boolean. Update it such that it returns %true on success and %false on failure. * Make sure the caller checks for the return value. * Separate out __blk_get_queue() which doesn't check whether @q is dead and put it in blk.h. This will be used later. This patch doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block, cfq: move cfqd->cic_index to q->idTejun Heo2011-12-13
| | | | | | | | | | | | | | | | | | | | | | | | cfq allocates per-queue id using ida and uses it to index cic radix tree from io_context. Move it to q->id and allocate on queue init and free on queue release. This simplifies cfq a bit and will allow for further improvements of io context life-cycle management. This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: add blk_queue_dead()Tejun Heo2011-12-13
| | | | | | | | | | | | | | | | | | | | There are a number of QUEUE_FLAG_DEAD tests. Add blk_queue_dead() macro and use it. This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block, sx8: kill blk_insert_request()Tejun Heo2011-12-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The only user left for blk_insert_request() is sx8 and it can be trivially switched to use blk_execute_rq_nowait() - special requests aren't included in io stat and sx8 doesn't use block layer tagging. Switch sx8 and kill blk_insert_requeset(). This patch doesn't introduce any functional difference. Only compile tested. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Jeff Garzik <jgarzik@pobox.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | block: fail SCSI passthrough ioctls on partition devicesPaolo Bonzini2012-01-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Linux allows executing the SG_IO ioctl on a partition or LVM volume, and will pass the command to the underlying block device. This is well-known, but it is also a large security problem when (via Unix permissions, ACLs, SELinux or a combination thereof) a program or user needs to be granted access only to part of the disk. This patch lets partitions forward a small set of harmless ioctls; others are logged with printk so that we can see which ioctls are actually sent. In my tests only CDROM_GET_CAPABILITY actually occurred. Of course it was being sent to a (partition on a) hard disk, so it would have failed with ENOTTY and the patch isn't changing anything in practice. Still, I'm treating it specially to avoid spamming the logs. In principle, this restriction should include programs running with CAP_SYS_RAWIO. If for example I let a program access /dev/sda2 and /dev/sdb, it still should not be able to read/write outside the boundaries of /dev/sda2 independent of the capabilities. However, for now programs with CAP_SYS_RAWIO will still be allowed to send the ioctls. Their actions will still be logged. This patch does not affect the non-libata IDE driver. That driver however already tests for bd != bd->bd_contains before issuing some ioctl; it could be restricted further to forbid these ioctls even for programs running with CAP_SYS_ADMIN/CAP_SYS_RAWIO. Cc: linux-scsi@vger.kernel.org Cc: Jens Axboe <axboe@kernel.dk> Cc: James Bottomley <JBottomley@parallels.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [ Make it also print the command name when warning - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | block: add and use scsi_blk_cmd_ioctlPaolo Bonzini2012-01-14
| | | | | | | | | | | | | | | | | | | | | | | | | | Introduce a wrapper around scsi_cmd_ioctl that takes a block device. The function will then be enhanced to detect partition block devices and, in that case, subject the ioctls to whitelisting. Cc: linux-scsi@vger.kernel.org Cc: Jens Axboe <axboe@kernel.dk> Cc: James Bottomley <JBottomley@parallels.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | block: initialize request_queue's numa node duringMike Snitzer2011-11-23
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | struct request_queue is allocated with __GFP_ZERO so its "node" field is zero before initialization. This causes an oops if node 0 is offline in the page allocator because its zonelists are not initialized. From Dave Young's dmesg: SRAT: Node 1 PXM 2 0-d0000000 SRAT: Node 1 PXM 2 100000000-330000000 SRAT: Node 0 PXM 1 330000000-630000000 Initmem setup node 1 0000000000000000-000000000affb000 ... Built 1 zonelists in Node order, mobility grouping on. ... BUG: unable to handle kernel paging request at 0000000000001c08 IP: [<ffffffff8111c355>] __alloc_pages_nodemask+0xb5/0x870 and __alloc_pages_nodemask+0xb5 translates to a NULL pointer on zonelist->_zonerefs. The fix is to initialize q->node at the time of allocation so the correct node is passed to the slab allocator later. Since blk_init_allocated_queue_node() is no longer needed, merge it with blk_init_allocated_queue(). [rientjes@google.com: changelog, initializing q->node] Cc: stable@vger.kernel.org [2.6.37+] Reported-by: Dave Young <dyoung@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: David Rientjes <rientjes@google.com> Tested-by: Dave Young <dyoung@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge branch 'modsplit-Oct31_2011' of ↵Linus Torvalds2011-11-06
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux * 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits) Revert "tracing: Include module.h in define_trace.h" irq: don't put module.h into irq.h for tracking irqgen modules. bluetooth: macroize two small inlines to avoid module.h ip_vs.h: fix implicit use of module_get/module_put from module.h nf_conntrack.h: fix up fallout from implicit moduleparam.h presence include: replace linux/module.h with "struct module" wherever possible include: convert various register fcns to macros to avoid include chaining crypto.h: remove unused crypto_tfm_alg_modname() inline uwb.h: fix implicit use of asm/page.h for PAGE_SIZE pm_runtime.h: explicitly requires notifier.h linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h miscdevice.h: fix up implicit use of lists and types stop_machine.h: fix implicit use of smp.h for smp_processor_id of: fix implicit use of errno.h in include/linux/of.h of_platform.h: delete needless include <linux/module.h> acpi: remove module.h include from platform/aclinux.h miscdevice.h: delete unnecessary inclusion of module.h device_cgroup.h: delete needless include <linux/module.h> net: sch_generic remove redundant use of <linux/module.h> net: inet_timewait_sock doesnt need <linux/module.h> ... Fix up trivial conflicts (other header files, and removal of the ab3550 mfd driver) in - drivers/media/dvb/frontends/dibx000_common.c - drivers/media/video/{mt9m111.c,ov6650.c} - drivers/mfd/ab3550-core.c - include/linux/dmaengine.h
| * include: replace linux/module.h with "struct module" wherever possiblePaul Gortmaker2011-10-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The <linux/module.h> pretty much brings in the kitchen sink along with it, so it should be avoided wherever reasonably possible in terms of being included from other commonly used <linux/something.h> files, as it results in a measureable increase on compile times. The worst culprit was probably device.h since it is used everywhere. This file also had an implicit dependency/usage of mutex.h which was masked by module.h, and is also fixed here at the same time. There are over a dozen other headers that simply declare the struct instead of pulling in the whole file, so follow their lead and simply make it a few more. Most of the implicit dependencies on module.h being present by these headers pulling it in have been now weeded out, so we can finally make this change with hopefully minimal breakage. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
* | block: move blk_throtl prototypes to block/blk.hTejun Heo2011-10-19
| | | | | | | | | | | | | | | | | | | | | | blk_throtl interface is block internal and there's no reason to have them in linux/blkdev.h. Move them to block/blk.h. This patch doesn't introduce any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | Merge branch 'v3.1-rc10' into for-3.2/coreJens Axboe2011-10-19
|\| | | | | | | | | | | | | | | Conflicts: block/blk-core.c include/linux/blkdev.h Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: simplify force plug flush code a little bitShaohua Li2011-08-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Cleaning up the code a little bit. attempt_plug_merge() traverses the plug list anyway, we can do the request counting there, so stack size is reduced a little bit. The motivation here is I suspect if we should count the requests for each queue (task could handle multiple disks in the meantime), but my test doesn't show it's worthy doing. If somebody proves we should do it, below change will make that more easier. Signed-off-by: Shaohua Li <shli@kernel.org> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * block: fix flush machinery for stacking drivers with differring flush flagsJeff Moyer2011-08-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit ae1b1539622fb46e51b4d13b3f9e5f4c713f86ae, block: reimplement FLUSH/FUA to support merge, introduced a performance regression when running any sort of fsyncing workload using dm-multipath and certain storage (in our case, an HP EVA). The test I ran was fs_mark, and it dropped from ~800 files/sec on ext4 to ~100 files/sec. It turns out that dm-multipath always advertised flush+fua support, and passed commands on down the stack, where those flags used to get stripped off. The above commit changed that behavior: static inline struct request *__elv_next_request(struct request_queue *q) { struct request *rq; while (1) { - while (!list_empty(&q->queue_head)) { + if (!list_empty(&q->queue_head)) { rq = list_entry_rq(q->queue_head.next); - if (!(rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) || - (rq->cmd_flags & REQ_FLUSH_SEQ)) - return rq; - rq = blk_do_flush(q, rq); - if (rq) - return rq; + return rq; } Note that previously, a command would come in here, have REQ_FLUSH|REQ_FUA set, and then get handed off to blk_do_flush: struct request *blk_do_flush(struct request_queue *q, struct request *rq) { unsigned int fflags = q->flush_flags; /* may change, cache it */ bool has_flush = fflags & REQ_FLUSH, has_fua = fflags & REQ_FUA; bool do_preflush = has_flush && (rq->cmd_flags & REQ_FLUSH); bool do_postflush = has_flush && !has_fua && (rq->cmd_flags & REQ_FUA); unsigned skip = 0; ... if (blk_rq_sectors(rq) && !do_preflush && !do_postflush) { rq->cmd_flags &= ~REQ_FLUSH; if (!has_fua) rq->cmd_flags &= ~REQ_FUA; return rq; } So, the flush machinery was bypassed in such cases (q->flush_flags == 0 && rq->cmd_flags & (REQ_FLUSH|REQ_FUA)). Now, however, we don't get into the flush machinery at all. Instead, __elv_next_request just hands a request with flush and fua bits set to the scsi_request_fn, even if the underlying request_queue does not support flush or fua. The agreed upon approach is to fix the flush machinery to allow stacking. While this isn't used in practice (since there is only one request-based dm target, and that target will now reflect the flush flags of the underlying device), it does future-proof the solution, and make it function as designed. In order to make this work, I had to add a field to the struct request, inside the flush structure (to store the original req->end_io). Shaohua had suggested overloading the union with rb_node and completion_data, but the completion data is used by device mapper and can also be used by other drivers. So, I didn't see a way around the additional field. I tested this patch on an HP EVA with both ext4 and xfs, and it recovers the lost performance. Comments and other testers, as always, are appreciated. Cheers, Jeff Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * block: add bsg helper libraryMike Christie2011-07-31
| | | | | | | | | | | | | | | | | | | | | | | | | | This moves the FC classes bsg code to the block layer and makes it a lib so that other classes like iscsi and SAS can use it. It is helpful because working with the request queue, bios, creating scatterlists, etc are a pain that the LLD does not have to worry about with normal IOs and should not have to worry about for bsg requests. Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | block: document blk-plugSuresh Jayaraman2011-09-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Thus spake Andrew Morton: "And I have the usual maintainability whine. If someone comes up to vmscan.c and sees it calling blk_start_plug(), how are they supposed to work out why that call is there? They go look at the blk_start_plug() definition and it is undocumented. I think we can do better than this?" Adapted from the LWN article - http://lwn.net/Articles/438256/ by Jens Axboe and from an earlier attempt by Shaohua Li to document blk-plug. [akpm@linux-foundation.org: grammatical and spelling tweaks] Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | block: remove support for bio remapping from ->make_requestChristoph Hellwig2011-09-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is very little benefit in allowing to let a ->make_request instance update the bios device and sector and loop around it in __generic_make_request when we can archive the same through calling generic_make_request from the driver and letting the loop in generic_make_request handle it. Note that various drivers got the return value from ->make_request and returned non-zero values for errors. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: NeilBrown <neilb@suse.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | block: rename __make_request() to blk_queue_bio()Jens Axboe2011-09-12
| | | | | | | | | | | | Now that it's exported, lets put it in a more sane namespace. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | block: export __make_requestChristoph Hellwig2011-09-12
|/ | | | | | | | Avoid the hacks need for request based device mappers currently by simply exporting the symbol instead of trying to get it through the back door. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: strict rq_affinityDan Williams2011-07-23
| | | | | | | | | | | | | | | | | | | | | Some systems benefit from completions always being steered to the strict requester cpu rather than the looser "per-socket" steering that blk_cpu_to_group() attempts by default. This is because the first CPU in the group mask ends up being completely overloaded with work, while the others (including the original submitter) has power left to spare. Allow the strict mode to be set by writing '2' to the sysfs control file. This is identical to the scheme used for the nomerges file, where '2' is a more aggressive setting than just being turned on. echo 2 > /sys/block/<bdev>/queue/rq_affinity Cc: Christoph Hellwig <hch@infradead.org> Cc: Roland Dreier <roland@purestorage.com> Tested-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: reorder request_queue to remove 64 bit alignment paddingRichard Kennedy2011-07-13
| | | | | | | | | | | | | | | Reorder request_queue to remove 16 bytes of alignment padding in 64 bit builds. On my config this shrinks the size of this structure from 1608 to 1592 bytes and therefore needs one fewer cachelines. Also trivially move the open bracket { to be on the same line as the structure name to make it easier to grep. Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: document blk_plug list accessShaohua Li2011-07-08
| | | | | | | | I'm often confused why not disable preempt when changing blk_plug list. It would be better to add comments here in case others have the similar concerns. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: avoid building too big plug listShaohua Li2011-07-08
| | | | | | | | | | | | | | | | | | | When I test fio script with big I/O depth, I found the total throughput drops compared to some relative small I/O depth. The reason is the thread accumulates big requests in its plug list and causes some delays (surely this depends on CPU speed). I thought we'd better have a threshold for requests. When a threshold reaches, this means there is no request merge and queue lock contention isn't severe when pushing per-task requests to queue, so the main advantages of blk plug don't exist. We can force a plug list flush in this case. With this, my test throughput actually increases and almost equals to small I/O depth. Another side effect is irq off time decreases in blk_flush_plug_list() for big I/O depth. The BLK_MAX_REQUEST_COUNT is choosen arbitarily, but 16 is efficiently to reduce lock contention to me. But I'm open here, 32 is ok in my test too. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* Merge branch 'for-linus' into for-3.1/coreJens Axboe2011-07-01
|\ | | | | | | | | | | | | | | Conflicts: block/blk-throttle.c block/cfq-iosched.c Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * block: remove unwanted semicolonsNamhyung Kim2011-05-31
| | | | | | | | | | | | | | | | | | | | Since those defined functions require additional semicolon from the caller, they could cause potential syntax errors when used in if-else statements. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | block:fix the comment error in blkdev.hWanlong Gao2011-06-13
|/ | | | | | | There is not a function rq_init but blk_rq_init in block/blk-core.c. Signed-off-by: Wanlong Gao <wanlong.gao@gmail.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* Merge commit 'v2.6.39' into for-2.6.40/coreJens Axboe2011-05-20
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since for-2.6.40/core was forked off the 2.6.39 devel tree, we've had churn in the core area that makes it difficult to handle patches for eg cfq or blk-throttle. Instead of requiring that they be based in older versions with bugs that have been fixed later in the rc cycle, merge in 2.6.39 final. Also fixes up conflicts in the below files. Conflicts: drivers/block/paride/pcd.c drivers/cdrom/viocd.c drivers/ide/ide-cd.c Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * block: get rid of QUEUE_FLAG_REENTERJens Axboe2011-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We are currently using this flag to check whether it's safe to call into ->request_fn(). If it is set, we punt to kblockd. But we get a lot of false positives and excessive punts to kblockd, which hurts performance. The only real abuser of this infrastructure is SCSI. So export the async queue run and convert SCSI over to use that. There's room for improvement in that SCSI need not always use the async call, but this fixes our performance issue and they can fix that up in due time. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | block: Fix discard topology stacking and reportingMartin K. Petersen2011-05-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In some cases we would end up stacking discard_zeroes_data incorrectly. Fix this by enabling the feature by default for stacking drivers and clearing it for low-level drivers. Incorporating a device that does not support dzd will then cause the feature to be disabled in the stacking driver. Also ensure that the maximum discard value does not overflow when exported in sysfs and return 0 in the alignment and dzd fields for devices that don't support discard. Reported-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@kernel.org Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | block: hold queue if flush is running for non-queueable flush driveshaohua.li@intel.com2011-05-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In some drives, flush requests are non-queueable. When flush request is running, normal read/write requests can't run. If block layer dispatches such request, driver can't handle it and requeue it. Tejun suggested we can hold the queue when flush is running. This can avoid unnecessary requeue. Also this can improve performance. For example, we have request flush1, write1, flush 2. flush1 is dispatched, then queue is hold, write1 isn't inserted to queue. After flush1 is finished, flush2 will be dispatched. Since disk cache is already clean, flush2 will be finished very soon, so looks like flush2 is folded to flush1. In my test, the queue holding completely solves a regression introduced by commit 53d63e6b0dfb95882ec0219ba6bbd50cde423794: block: make the flush insertion use the tail of the dispatch list It's not a preempt type request, in fact we have to insert it behind requests that do specify INSERT_FRONT. which causes about 20% regression running a sysbench fileio workload. Stable: 2.6.39 only Cc: stable@kernel.org Signed-off-by: Shaohua Li <shaohua.li@intel.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | block: add a non-queueable flush flagshaohua.li@intel.com2011-05-06
|/ | | | | | | | | | | | | flush request isn't queueable in some drives. Add a flag to let driver notify block layer about this. We can optimize flush performance with the knowledge. Stable: 2.6.39 only Cc: stable@kernel.org Signed-off-by: Shaohua Li <shaohua.li@intel.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: add blk_run_queue_asyncChristoph Hellwig2011-04-18
| | | | | | | | | | Instead of overloading __blk_run_queue to force an offload to kblockd add a new blk_run_queue_async helper to do it explicitly. I've kept the blk_queue_stopped check for now, but I suspect it's not needed as the check we do when the workqueue items runs should be enough. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* Revert "block: add callback function for unplug notification"Jens Axboe2011-04-18
| | | | | | | | | | | | | | | MD can't use this since it really requires us to be able to keep more than a single piece of state for the unplug. Commit 048c9374 added the required support for MD, so get rid of this now unused code. This reverts commit f75664570d8b75469cc468f23c2b27220984983b. Conflicts: block/blk-core.c Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: Enhance new plugging support to support general callbacksNeilBrown2011-04-18
| | | | | | | | | | md/raid requires an unplug callback, but as it does not uses requests the current code cannot provide one. So allow arbitrary callbacks to be attached to the blk_plug. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: let io_schedule() flush the plug inlineJens Axboe2011-04-16
| | | | | | | | | | | | | | Linus correctly observes that the most important dispatch cases are now done from kblockd, this isn't ideal for latency reasons. The original reason for switching dispatches out-of-line was to avoid too deep a stack, so by _only_ letting the "accidental" flush directly in schedule() be guarded by offload to kblockd, we should be able to get the best of both worlds. So add a blk_schedule_flush_plug() that offloads to kblockd, and only use that from the schedule() path. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: only force kblockd unplugging from the schedule() pathJens Axboe2011-04-15
| | | | | | | | | For the explicit unplugging, we'd prefer to kick things off immediately and not pay the penalty of the latency to switch to kblockd. So let blk_finish_plug() do the run inline, while the implicit-on-schedule-out unplug will punt to kblockd. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: cleanup the block plug helper functionsChristoph Hellwig2011-04-15
| | | | | | | | | | | | It's a bit of a mess currently. task->plug is being cleared and reset in __blk_finish_plug(), and blk_finish_plug() is testing for a NULL plug which cannot happen even from schedule() anymore since it uses blk_needs_flush_plug() to determine whether to call into this function at all. So get rid of some of the cruft. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: add callback function for unplug notificationJens Axboe2011-04-12
| | | | | | | MD would like to know when a queue is unplugged, so it can flush it's bitmap writes. Add such a callback. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* dm: improve block integrity supportMike Snitzer2011-04-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current block integrity (DIF/DIX) support in DM is verifying that all devices' integrity profiles match during DM device resume (which is past the point of no return). To some degree that is unavoidable (stacked DM devices force this late checking). But for most DM devices (which aren't stacking on other DM devices) the ideal time to verify all integrity profiles match is during table load. Introduce the notion of an "initialized" integrity profile: a profile that was blk_integrity_register()'d with a non-NULL 'blk_integrity' template. Add blk_integrity_is_initialized() to allow checking if a profile was initialized. Update DM integrity support to: - check all devices with _initialized_ integrity profiles match during table load; uninitialized profiles (e.g. for underlying DM device(s) of a stacked DM device) are ignored. - disallow a table load that would result in an integrity profile that conflicts with a DM device's existing (in-use) integrity profile - avoid clearing an existing integrity profile - validate all integrity profiles match during resume; but if they don't all we can do is report the mismatch (during resume we're past the point of no return) Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: fixup plugging stubs for !CONFIG_BLOCKJens Axboe2011-03-11
| | | | | | | They used an older prototype, fix it up. Reported-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* Merge branch 'for-2.6.39/stack-plug' into for-2.6.39/coreJens Axboe2011-03-10
|\ | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: block/blk-core.c block/blk-flush.c drivers/md/raid1.c drivers/md/raid10.c drivers/md/raid5.c fs/nilfs2/btnode.c fs/nilfs2/mdt.c Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * block: remove per-queue pluggingJens Axboe2011-03-10
| | | | | | | | | | | | | | | | Code has been converted over to the new explicit on-stack plugging, and delay users have been converted to use the new API for that. So lets kill off the old plugging along with aops->sync_page(). Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * block: initial patch for on-stack per-task pluggingJens Axboe2011-03-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds support for creating a queuing context outside of the queue itself. This enables us to batch up pieces of IO before grabbing the block device queue lock and submitting them to the IO scheduler. The context is created on the stack of the process and assigned in the task structure, so that we can auto-unplug it if we hit a schedule event. The current queue plugging happens implicitly if IO is submitted to an empty device, yet callers have to remember to unplug that IO when they are going to wait for it. This is an ugly API and has caused bugs in the past. Additionally, it requires hacks in the vm (->sync_page() callback) to handle that logic. By switching to an explicit plugging scheme we make the API a lot nicer and can get rid of the ->sync_page() hack in the vm. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * block: add API for delaying work/request_fn a little bitJens Axboe2011-03-10
| | | | | | | | | | | | | | Currently we use plugging for that, but as plugging is going away, we need an alternative mechanism. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | Merge branch 'for-linus' of ../linux-2.6-block into block-for-2.6.39/coreTejun Heo2011-03-04
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This merge creates two set of conflicts. One is simple context conflicts caused by removal of throtl_scheduled_delayed_work() in for-linus and removal of throtl_shutdown_timer_wq() in for-2.6.39/core. The other is caused by commit 255bb490c8 (block: blk-flush shouldn't call directly into q->request_fn() __blk_run_queue()) in for-linus crashing with FLUSH reimplementation in for-2.6.39/core. The conflict isn't trivial but the resolution is straight-forward. * __blk_run_queue() calls in flush_end_io() and flush_data_end_io() should be called with @force_kblockd set to %true. * elv_insert() in blk_kick_flush() should use %ELEVATOR_INSERT_REQUEUE. Both changes are to avoid invoking ->request_fn() directly from request completion path and closely match the changes in the commit 255bb490c8. Signed-off-by: Tejun Heo <tj@kernel.org>
| * | block: add @force_kblockd to __blk_run_queue()Tejun Heo2011-03-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __blk_run_queue() automatically either calls q->request_fn() directly or schedules kblockd depending on whether the function is recursed. blk-flush implementation needs to be able to explicitly choose kblockd. Add @force_kblockd. All the current users are converted to specify %false for the parameter and this patch doesn't introduce any behavior change. stable: This is prerequisite for fixing ide oops caused by the new blk-flush implementation. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jan Beulich <JBeulich@novell.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: stable@kernel.org Signed-off-by: Jens Axboe <jaxboe@fusionio.com>