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2013-01-09cfq-iosched: collect stats from dead cfqgsTejun Heo
To support hierarchical stats, it's necessary to remember stats from dead children. Add cfqg->dead_stats and make a dying cfqg transfer its stats to the parent's dead-stats. The transfer happens form ->pd_offline_fn() and it is possible that there are some residual IOs completing afterwards. Currently, we lose these stats. Given that cgroup removal isn't a very high frequency operation and the amount of residual IOs on offline are likely to be nil or small, this shouldn't be a big deal and the complexity needed to handle residual IOs - another callback and rather elaborate synchronization to reach and lock the matching q - doesn't seem justified. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09cfq-iosched: separate out cfqg_stats_reset() from cfq_pd_reset_stats()Tejun Heo
Separate out cfqg_stats_reset() which takes struct cfqg_stats * from cfq_pd_reset_stats() and move the latter to where other pd methods are defined. cfqg_stats_reset() will be used to implement hierarchical stats. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09blkcg: make blkcg_print_blkgs() grab q locks instead of blkcg lockTejun Heo
Instead of holding blkcg->lock while walking ->blkg_list and executing prfill(), RCU walk ->blkg_list and hold the blkg's queue lock while executing prfill(). This makes prfill() implementations easier as stats are mostly protected by queue lock. This will be used to implement hierarchical stats. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09block: RCU free request_queueTejun Heo
RCU free request_queue so that blkcg_gq->q can be dereferenced under RCU lock. This will be used to implement hierarchical stats. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09blkcg: implement blkg_[rw]stat_recursive_sum() and blkg_[rw]stat_merge()Tejun Heo
Implement blkg_[rw]stat_recursive_sum() and blkg_[rw]stat_merge(). The former two collect the [rw]stats designated by the target policy data and offset from the pd's subtree. The latter two add one [rw]stat to another. Note that the recursive sum functions require the queue lock to be held on entry to make blkg online test reliable. This is necessary to properly handle stats of a dying blkg. These will be used to implement hierarchical stats. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09blkcg: export __blkg_prfill_rwstat()Tejun Heo
Hierarchical stats for cfq-iosched will need __blkg_prfill_rwstat(). Export it. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
2013-01-09blkcg: s/blkg_rwstat_sum()/blkg_rwstat_total()/Tejun Heo
Rename blkg_rwstat_sum() to blkg_rwstat_total(). sum will be used for summing up stats from multiple blkgs. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09blkcg: implement blkcg_policy->on/offline_pd_fn() and blkcg_gq->onlineTejun Heo
Add two blkcg_policy methods, ->online_pd_fn() and ->offline_pd_fn(), which are invoked as the policy_data gets activated and deactivated while holding both blkcg and q locks. Also, add blkcg_gq->online bool, which is set and cleared as the blkcg_gq gets activated and deactivated. This flag also is toggled while holding both blkcg and q locks. These will be used to implement hierarchical stats. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09blkcg: add blkg_policy_data->plidTejun Heo
Add pd->plid so that the policy a pd belongs to can be identified easily. This will be used to implement hierarchical blkg_[rw]stats. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09cfq-iosched: enable full blkcg hierarchy supportTejun Heo
With the previous two patches, all cfqg scheduling decisions are based on vfraction and ready for hierarchy support. The only thing which keeps the behavior flat is cfqg_flat_parent() which makes vfraction calculation consider all non-root cfqgs children of the root cfqg. Replace it with cfqg_parent() which returns the real parent. This enables full blkcg hierarchy support for cfq-iosched. For example, consider the following hierarchy. root / \ A:500 B:250 / \ AA:500 AB:1000 For simplicity, let's say all the leaf nodes have active tasks and are on service tree. For each leaf node, vfraction would be AA: (500 / 1500) * (500 / 750) =~ 0.2222 AB: (1000 / 1500) * (500 / 750) =~ 0.4444 B: (250 / 750) =~ 0.3333 and vdisktime will be distributed accordingly. For more detail, please refer to Documentation/block/cfq-iosched.txt. v2: cfq-iosched.txt updated to describe group scheduling as suggested by Vivek. v3: blkio-controller.txt updated. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09cfq-iosched: convert cfq_group_slice() to use cfqg->vfractionTejun Heo
cfq_group_slice() calculates slice by taking a fraction of cfq_target_latency according to the ratio of cfqg->weight against service_tree->total_weight. This currently works only because all cfqgs are treated to be at the same level. To prepare for proper hierarchy support, convert cfq_group_slice() to base the calculation on cfqg->vfraction. As cfqg->vfraction is always a fraction of 1 and represents the fraction allocated to the cfqg with hierarchy considered, the slice can be simply calculated by multiplying cfqg->vfraction to cfq_target_latency (with fixed point shift factored in). As vfraction calculation currently treats all non-root cfqgs as children of the root cfqg, this patch doesn't introduce noticeable behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09cfq-iosched: implement hierarchy-ready cfq_group charge scalingTejun Heo
Currently, cfqg charges are scaled directly according to cfqg->weight. Regardless of the number of active cfqgs or the amount of active weights, a given weight value always scales charge the same way. This works fine as long as all cfqgs are treated equally regardless of their positions in the hierarchy, which is what cfq currently implements. It can't work in hierarchical settings because the interpretation of a given weight value depends on where the weight is located in the hierarchy. This patch reimplements cfqg charge scaling so that it can be used to support hierarchy properly. The scheme is fairly simple and light-weight. * When a cfqg is added to the service tree, v(disktime)weight is calculated. It walks up the tree to root calculating the fraction it has in the hierarchy. At each level, the fraction can be calculated as cfqg->weight / parent->level_weight By compounding these, the global fraction of vdisktime the cfqg has claim to - vfraction - can be determined. * When the cfqg needs to be charged, the charge is scaled inversely proportionally to the vfraction. The new scaling scheme uses the same CFQ_SERVICE_SHIFT for fixed point representation as before; however, the smallest scaling factor is now 1 (ie. 1 << CFQ_SERVICE_SHIFT). This is different from before where 1 was for CFQ_WEIGHT_DEFAULT and higher weight would result in smaller scaling factor. While this shifts the global scale of vdisktime a bit, it doesn't change the relative relationships among cfqgs and the scheduling result isn't different. cfq_group_notify_queue_add uses fixed CFQ_IDLE_DELAY when appending new cfqg to the service tree. The specific value of CFQ_IDLE_DELAY didn't have any relevance to vdisktime before and is unlikely to cause any visible behavior difference now especially as the scale shift isn't that large. As the new scheme now makes proper distinction between cfqg->weight and ->leaf_weight, reverse the weight aliasing for root cfqgs. For root, both weights are now mapped to ->leaf_weight instead of the other way around. Because we're still using cfqg_flat_parent(), this patch shouldn't change the scheduling behavior in any noticeable way. v2: Beefed up comments on vfraction as requested by Vivek. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09cfq-iosched: implement cfq_group->nr_active and ->children_weightTejun Heo
To prepare for blkcg hierarchy support, add cfqg->nr_active and ->children_weight. cfqg->nr_active counts the number of active cfqgs at the cfqg's level and ->children_weight is sum of weights of those cfqgs. The level covers itself (cfqg->leaf_weight) and immediate children. The two values are updated when a cfqg enters and leaves the group service tree. Unless the hierarchy is very deep, the added overhead should be negligible. Currently, the parent is determined using cfqg_flat_parent() which makes the root cfqg the parent of all other cfqgs. This is to make the transition to hierarchy-aware scheduling gradual. Scheduling logic will be converted to use cfqg->children_weight without actually changing the behavior. When everything is ready, blkcg_weight_parent() will be replaced with proper parent function. This patch doesn't introduce any behavior chagne. v2: s/cfqg->level_weight/cfqg->children_weight/ as per Vivek. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09cfq-iosched: add leaf_weightTejun Heo
cfq blkcg is about to grow proper hierarchy handling, where a child blkg's weight would nest inside the parent's. This makes tasks in a blkg to compete against both tasks in the sibling blkgs and the tasks of child blkgs. We're gonna use the existing weight as the group weight which decides the blkg's weight against its siblings. This patch introduces a new weight - leaf_weight - which decides the weight of a blkg against the child blkgs. It's named leaf_weight because another way to look at it is that each internal blkg nodes have a hidden child leaf node which contains all its tasks and leaf_weight is the weight of the leaf node and handled the same as the weight of the child blkgs. This patch only adds leaf_weight fields and exposes it to userland. The new weight isn't actually used anywhere yet. Note that cfq-iosched currently offcially supports only single level hierarchy and root blkgs compete with the first level blkgs - ie. root weight is basically being used as leaf_weight. For root blkgs, the two weights are kept in sync for backward compatibility. v2: cfqd->root_group->leaf_weight initialization was missing from cfq_init_queue() causing divide by zero when !CONFIG_CFQ_GROUP_SCHED. Fix it. Reported by Fengguang. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Fengguang Wu <fengguang.wu@intel.com>
2013-01-09blkcg: make blkcg_gq's hierarchicalTejun Heo
Currently a child blkg (blkcg_gq) can be created even if its parent doesn't exist. ie. Given a blkg, it's not guaranteed that its ancestors will exist. This makes it difficult to implement proper hierarchy support for blkcg policies. Always create blkgs recursively and make a child blkg hold a reference to its parent. blkg->parent is added so that finding the parent is easy. blkcg_parent() is also added in the process. This change can be visible to userland. e.g. while issuing IO in a nested cgroup didn't affect the ancestors at all, now it will initialize all ancestor blkgs and zero stats for the request_queue will always appear on them. While this is userland visible, this shouldn't cause any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09blkcg: cosmetic updates to blkg_create()Tejun Heo
* Rename out_* labels to err_*. * Do ERR_PTR() conversion once in the error return path. This patch is cosmetic and to prepare for the hierarchy support. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09blkcg: reorganize blkg_lookup_create() and friendsTejun Heo
Reorganize such that * __blkg_lookup() takes bool param @update_hint to determine whether to update hint. * __blkg_lookup_create() no longer performs lookup before trying to create. Renamed to blkg_create(). * blkg_lookup_create() now performs lookup and then invokes blkg_create() if lookup fails. * root_blkg creation in blkcg_activate_policy() updated accordingly. Note that blkcg_activate_policy() no longer updates lookup hint if root_blkg already exists. Except for the last lookup hint bit which is immaterial, this is pure reorganization and doesn't introduce any visible behavior change. This is to prepare for proper hierarchy support. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09blkcg: fix minor bug in blkg_alloc()Tejun Heo
blkg_alloc() was mistakenly checking blkcg_policy_enabled() twice. The latter test should have been on whether pol->pd_init_fn() exists. This doesn't cause actual problems because both blkcg policies implement pol->pd_init_fn(). Fix it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-01-09cfq-iosched: Print sync-noidle information in blktrace messagesVivek Goyal
Currently we attach a character "S" or "A" to the cfqq<pid>, to represent whether queues is sync or async. Add one more character "N" to represent whether it is sync-noidle queue or sync queue. So now three different type of queues will look as follows. cfq1234S --> sync queus cfq1234SN --> sync noidle queue cfq1234A --> Async queue Previously S/A classification was being printed only if group scheduling was enabled. This patch also makes sure that this classification is displayed even if group idling is disabled. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2013-01-09cfq-iosched: Get rid of unnecessary local variableVivek Goyal
Use of local varibale "n" seems to be unnecessary. Remove it. This brings it inline with function __cfq_group_st_add(), which is also doing the similar operation of adding a group to a rb tree. No functionality change here. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2013-01-09cfq-iosched: Rename few functions related to selecting workloadVivek Goyal
choose_service_tree() selects/sets both wl_class and wl_type. Rename it to choose_wl_class_and_type() to make it very clear. cfq_choose_wl() only selects and sets wl_type. It is easy to confuse it with choose_st(). So rename it to cfq_choose_wl_type() to make it clear what does it do. Just renaming. No functionality change. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2013-01-09cfq-iosched: Rename "service_tree" to "st" at some placesVivek Goyal
At quite a few places we use the keyword "service_tree". At some places, especially local variables, I have abbreviated it to "st". Also at couple of places moved binary operator "+" from beginning of line to end of previous line, as per Tejun's feedback. v2: Reverted most of the service tree name change based on Jeff Moyer's feedback. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2013-01-09cfq-iosched: More renaming to better represent wl_class and wl_typeVivek Goyal
Some more renaming. Again making the code uniform w.r.t use of wl_class/class to represent IO class (RT, BE, IDLE) and using wl_type/type to represent subclass (SYNC, SYNC-IDLE, ASYNC). At places this patch shortens the string "workload" to "wl". Renamed "saved_workload" to "saved_wl_type". Renamed "saved_serving_class" to "saved_wl_class". For uniformity with "saved_wl_*" variables, renamed "serving_class" to "serving_wl_class" and renamed "serving_type" to "serving_wl_type". Again, just trying to improve upon code uniformity and improve readability. No functional change. v2: - Restored the usage of keyword "service" based on Jeff Moyer's feedback. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2013-01-09cfq-iosched: Properly name all references to IO classVivek Goyal
Currently CFQ has three IO classes, RT, BE and IDLE. At many a places we are calling workloads belonging to these classes as "prio". This gets very confusing as one starts to associate it with ioprio. So this patch just does bunch of renaming so that reading code becomes easier. All reference to RT, BE and IDLE workload are done using keyword "class" and all references to subclass, SYNC, SYNC-IDLE, ASYNC are made using keyword "type". This makes me feel much better while I am reading the code. There is no functionality change due to this patch. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2012-12-19block: prevent race/cleanupDerek Basehore
Remove a race condition which causes a warning in disk_clear_events. This is a race between disk_clear_events() and disk_flush_events(). ev->clearing will be altered by disk_flush_events() even though we are blocking event checking through disk_flush_events(). If this happens after ev->clearing was cleared for disk_clear_events(), this can cause the WARN_ON_ONCE() in that function to be triggered. This change also has disk_clear_events() not go through a workqueue. Since we have to wait for the work to complete, we should just call the function directly. Also, since this work cannot be put on a freezable workqueue, it will have to contend with increased demand, so calling the function directly avoids this. [akpm@linux-foundation.org: fix spello in comment] Signed-off-by: Derek Basehore <dbasehore@chromium.org> Cc: Mandeep Singh Baines <msb@chromium.org> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-19block: remove deadlock in disk_clear_eventsDerek Basehore
In disk_clear_events, do not put work on system_nrt_freezable_wq. Instead, put it on system_nrt_wq. There is a race between probing a usb and suspending the device. Since probing a usb calls disk_clear_events, which puts work on a frozen workqueue, probing cannot finish after the workqueue is frozen. However, suspending cannot finish until the usb probe is finished, so we get a deadlock, causing the system to reboot. The way to reproduce this bug is to wake up from suspend with a usb storage device plugged in, or plugging in a usb storage device right before suspend. The window of time is on the order of time it takes to probe the usb device. As long as the workqueues are frozen before the call to add_disk within sd_probe_async finishes, there will be a deadlock (which calls blkdev_get, sd_open, check_disk_change, then disk_clear_events). This is not difficult to reproduce after figuring out the timings. [akpm@linux-foundation.org: fix up comment] Signed-off-by: Derek Basehore <dbasehore@chromium.org> Reviewed-by: Mandeep Singh Baines <msb@chromium.org> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-17Merge branch 'akpm' (Andrew's patch-bomb)Linus Torvalds
Merge misc patches from Andrew Morton: "Incoming: - lots of misc stuff - backlight tree updates - lib/ updates - Oleg's percpu-rwsem changes - checkpatch - rtc - aoe - more checkpoint/restart support I still have a pile of MM stuff pending - Pekka should be merging later today after which that is good to go. A number of other things are twiddling thumbs awaiting maintainer merges." * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (180 commits) scatterlist: don't BUG when we can trivially return a proper error. docs: update documentation about /proc/<pid>/fdinfo/<fd> fanotify output fs, fanotify: add @mflags field to fanotify output docs: add documentation about /proc/<pid>/fdinfo/<fd> output fs, notify: add procfs fdinfo helper fs, exportfs: add exportfs_encode_inode_fh() helper fs, exportfs: escape nil dereference if no s_export_op present fs, epoll: add procfs fdinfo helper fs, eventfd: add procfs fdinfo helper procfs: add ability to plug in auxiliary fdinfo providers tools/testing/selftests/kcmp/kcmp_test.c: print reason for failure in kcmp_test breakpoint selftests: print failure status instead of cause make error kcmp selftests: print fail status instead of cause make error kcmp selftests: make run_tests fix mem-hotplug selftests: print failure status instead of cause make error cpu-hotplug selftests: print failure status instead of cause make error mqueue selftests: print failure status instead of cause make error vm selftests: print failure status instead of cause make error ubifs: use prandom_bytes mtd: nandsim: use prandom_bytes ...
2012-12-17percpu_rw_semaphore: introduce CONFIG_PERCPU_RWSEMOleg Nesterov
Currently only block_dev and uprobes use percpu_rw_semaphore, add the config option selected by BLOCK || UPROBES. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Anton Arapov <anton@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Marek <mmarek@suse.cz> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-17Merge branch 'for-3.8/drivers' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block driver update from Jens Axboe: "Now that the core bits are in, here are the driver bits for 3.8. The branch contains: - A huge pile of drbd bits that were dumped from the 3.7 merge window. Following that, it was both made perfectly clear that there is going to be no more over-the-wall pulls and how the situation on individual pulls can be improved. - A few cleanups from Akinobu Mita for drbd and cciss. - Queue improvement for loop from Lukas. This grew into adding a generic interface for waiting/checking an even with a specific lock, allowing this to be pulled out of md and now loop and drbd is also using it. - A few fixes for xen back/front block driver from Roger Pau Monne. - Partition improvements from Stephen Warren, allowing partiion UUID to be used as an identifier." * 'for-3.8/drivers' of git://git.kernel.dk/linux-block: (609 commits) drbd: update Kconfig to match current dependencies drbd: Fix drbdsetup wait-connect, wait-sync etc... commands drbd: close race between drbd_set_role and drbd_connect drbd: respect no-md-barriers setting also when changed online via disk-options drbd: Remove obsolete check drbd: fixup after wait_even_lock_irq() addition to generic code loop: Limit the number of requests in the bio list wait: add wait_event_lock_irq() interface xen-blkfront: free allocated page xen-blkback: move free persistent grants code block: partition: msdos: provide UUIDs for partitions init: reduce PARTUUID min length to 1 from 36 block: store partition_meta_info.uuid as a string cciss: use check_signature() cciss: cleanup bitops usage drbd: use copy_highpage drbd: if the replication link breaks during handshake, keep retrying drbd: check return of kmalloc in receive_uuids drbd: Broadcast sync progress no more often than once per second drbd: don't try to clear bits once the disk has failed ...
2012-12-17Merge branch 'for-3.8/core' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block layer core updates from Jens Axboe: "Here are the core block IO bits for 3.8. The branch contains: - The final version of the surprise device removal fixups from Bart. - Don't hide EFI partitions under advanced partition types. It's fairly wide spread these days. This is especially dangerous for systems that have both msdos and efi partition tables, where you want to keep them in sync. - Cleanup of using -1 instead of the proper NUMA_NO_NODE - Export control of bdi flusher thread CPU mask and default to using the home node (if known) from Jeff. - Export unplug tracepoint for MD. - Core improvements from Shaohua. Reinstate the recursive merge, as the original bug has been fixed. Add plugging for discard and also fix a problem handling non pow-of-2 discard limits. There's a trivial merge in block/blk-exec.c due to a fix that went into 3.7-rc at a later point than -rc4 where this is based." * 'for-3.8/core' of git://git.kernel.dk/linux-block: block: export block_unplug tracepoint block: add plug for blkdev_issue_discard block: discard granularity might not be power of 2 deadline: Allow 0ms deadline latency, increase the read speed partitions: enable EFI/GPT support by default bsg: Remove unused function bsg_goose_queue() block: Make blk_cleanup_queue() wait until request_fn finished block: Avoid scheduling delayed work on a dead queue block: Avoid that request_fn is invoked on a dead queue block: Let blk_drain_queue() caller obtain the queue lock block: Rename queue dead flag bdi: add a user-tunable cpu_list for the bdi flusher threads block: use NUMA_NO_NODE instead of -1 block: recursive merge requests block CFQ: avoid moving request to different queue
2012-12-14block: export block_unplug tracepointNeilBrown
This allows stacked devices (like md/raid5) to provide blktrace tracing, including unplug events. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-14block: add plug for blkdev_issue_discardShaohua Li
Last post of this patch appears lost, so I resend this. Now discard merge works, add plug for blkdev_issue_discard. This will help discard request merge especially for raid0 case. In raid0, a big discard request is split to small requests, and if correct plug is added, such small requests can be merged in low layer. Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-14block: discard granularity might not be power of 2Shaohua Li
In MD raid case, discard granularity might not be power of 2, for example, a 4-disk raid5 has 3*chunk_size discard granularity. Correct the calculation for such cases. Reported-by: Neil Brown <neilb@suse.de> Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-12Merge branch 'for-3.8' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup changes from Tejun Heo: "A lot of activities on cgroup side. The big changes are focused on making cgroup hierarchy handling saner. - cgroup_rmdir() had peculiar semantics - it allowed cgroup destruction to be vetoed by individual controllers and tried to drain refcnt synchronously. The vetoing never worked properly and caused good deal of contortions in cgroup. memcg was the last reamining user. Michal Hocko removed the usage and cgroup_rmdir() path has been simplified significantly. This was done in a separate branch so that the memcg people can base further memcg changes on top. - The above allowed cleaning up cgroup lifecycle management and implementation of generic cgroup iterators which are used to improve hierarchy support. - cgroup_freezer updated to allow migration in and out of a frozen cgroup and handle hierarchy. If a cgroup is frozen, all descendant cgroups are frozen. - netcls_cgroup and netprio_cgroup updated to handle hierarchy properly. - Various fixes and cleanups. - Two merge commits. One to pull in memcg and rmdir cleanups (needed to build iterators). The other pulled in cgroup/for-3.7-fixes for device_cgroup fixes so that further device_cgroup patches can be stacked on top." Fixed up a trivial conflict in mm/memcontrol.c as per Tejun (due to commit bea8c150a7 ("memcg: fix hotplugged memory zone oops") in master touching code close to commit 2ef37d3fe4 ("memcg: Simplify mem_cgroup_force_empty_list error handling") in for-3.8) * 'for-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (65 commits) cgroup: update Documentation/cgroups/00-INDEX cgroup_rm_file: don't delete the uncreated files cgroup: remove subsystem files when remounting cgroup cgroup: use cgroup_addrm_files() in cgroup_clear_directory() cgroup: warn about broken hierarchies only after css_online cgroup: list_del_init() on removed events cgroup: fix lockdep warning for event_control cgroup: move list add after list head initilization netprio_cgroup: allow nesting and inherit config on cgroup creation netprio_cgroup: implement netprio[_set]_prio() helpers netprio_cgroup: use cgroup->id instead of cgroup_netprio_state->prioidx netprio_cgroup: reimplement priomap expansion netprio_cgroup: shorten variable names in extend_netdev_table() netprio_cgroup: simplify write_priomap() netcls_cgroup: move config inheritance to ->css_online() and remove .broken_hierarchy marking cgroup: remove obsolete guarantee from cgroup_task_migrate. cgroup: add cgroup->id cgroup, cpuset: remove cgroup_subsys->post_clone() cgroup: s/CGRP_CLONE_CHILDREN/CGRP_CPUSET_CLONE_CHILDREN/ cgroup: rename ->create/post_create/pre_destroy/destroy() to ->css_alloc/online/offline/free() ...
2012-12-09deadline: Allow 0ms deadline latency, increase the read speedxiaobing tu
Change a timer compare from after to after-equals, thus allowing 0 timeout and making deadline schedule FIFO. Signed-off-by: xiaobing tu <xiaobing.tu@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-06partitions: enable EFI/GPT support by defaultDiego Calleja
The Kconfig currently enables MSDOS partitions by default because they are assumed to be essential, but it's necessary to enable "advanced partition selection" in order to get GPT support. IMO GPT partitions are becoming common enought to deserve the same treatment MSDOS partitions get. (Side note: I got bit by a disk that had MSDOS and GPT partition tables, but for some reason the MSDOS table was different from the GPT one. I was stupid enought to disable "advanced partition selection" in my .config, which disabled GPT partitioning and made my btrfs pool unbootable because it couldn't find the partitions) Signed-off-by: Diego Calleja <diegocg@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-06bsg: Remove unused function bsg_goose_queue()Bart Van Assche
The function bsg_goose_queue() does not have any in-tree callers, so let's remove it. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-06block: Make blk_cleanup_queue() wait until request_fn finishedBart Van Assche
Some request_fn implementations, e.g. scsi_request_fn(), unlock the queue lock internally. This may result in multiple threads executing request_fn for the same queue simultaneously. Keep track of the number of active request_fn calls and make sure that blk_cleanup_queue() waits until all active request_fn invocations have finished. A block driver may start cleaning up resources needed by its request_fn as soon as blk_cleanup_queue() finished, so blk_cleanup_queue() must wait for all outstanding request_fn invocations to finish. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reported-by: Chanho Min <chanho.min@lge.com> Cc: James Bottomley <JBottomley@Parallels.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-06block: Avoid scheduling delayed work on a dead queueBart Van Assche
Running a queue must continue after it has been marked dying until it has been marked dead. So the function blk_run_queue_async() must not schedule delayed work after blk_cleanup_queue() has marked a queue dead. Hence add a test for that queue state in blk_run_queue_async() and make sure that queue_unplugged() invokes that function with the queue lock held. This avoids that the queue state can change after it has been tested and before mod_delayed_work() is invoked. Drop the queue dying test in queue_unplugged() since it is now superfluous: __blk_run_queue() already tests whether or not the queue is dead. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Cc: Mike Christie <michaelc@cs.wisc.edu> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-06block: Avoid that request_fn is invoked on a dead queueBart Van Assche
A block driver may start cleaning up resources needed by its request_fn as soon as blk_cleanup_queue() finished, so request_fn must not be invoked after draining finished. This is important when blk_run_queue() is invoked without any requests in progress. As an example, if blk_drain_queue() and scsi_run_queue() run in parallel, blk_drain_queue() may have finished all requests after scsi_run_queue() has taken a SCSI device off the starved list but before that last function has had a chance to run the queue. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Cc: James Bottomley <JBottomley@Parallels.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Chanho Min <chanho.min@lge.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-06block: Let blk_drain_queue() caller obtain the queue lockBart Van Assche
Let the caller of blk_drain_queue() obtain the queue lock to improve readability of the patch called "Avoid that request_fn is invoked on a dead queue". Signed-off-by: Bart Van Assche <bvanassche@acm.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: James Bottomley <JBottomley@Parallels.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Jens Axboe <axboe@kernel.dk> Cc: Chanho Min <chanho.min@lge.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-06block: Rename queue dead flagBart Van Assche
QUEUE_FLAG_DEAD is used to indicate that queuing new requests must stop. After this flag has been set queue draining starts. However, during the queue draining phase it is still safe to invoke the queue's request_fn, so QUEUE_FLAG_DYING is a better name for this flag. This patch has been generated by running the following command over the kernel source tree: git grep -lEw 'blk_queue_dead|QUEUE_FLAG_DEAD' | xargs sed -i.tmp -e 's/blk_queue_dead/blk_queue_dying/g' \ -e 's/QUEUE_FLAG_DEAD/QUEUE_FLAG_DYING/g'; \ sed -i.tmp -e "s/QUEUE_FLAG_DYING$(printf \\t)*5/QUEUE_FLAG_DYING$(printf \\t)5/g" \ include/linux/blkdev.h; \ sed -i.tmp -e 's/ DEAD/ DYING/g' -e 's/dead queue/a dying queue/' \ -e 's/Dead queue/A dying queue/' block/blk-core.c Signed-off-by: Bart Van Assche <bvanassche@acm.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: James Bottomley <JBottomley@Parallels.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Jens Axboe <axboe@kernel.dk> Cc: Chanho Min <chanho.min@lge.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-11-23block: Don't access request after it might be freedRoland Dreier
After we've done __elv_add_request() and __blk_run_queue() in blk_execute_rq_nowait(), the request might finish and be freed immediately. Therefore checking if the type is REQ_TYPE_PM_RESUME isn't safe afterwards, because if it isn't, rq might be gone. Instead, check beforehand and stash the result in a temporary. This fixes crashes in blk_execute_rq_nowait() I get occasionally when running with lots of memory debugging options enabled -- I think this race is usually harmless because the window for rq to be reallocated is so small. Signed-off-by: Roland Dreier <roland@purestorage.com> Cc: stable@kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-11-23block: partition: msdos: provide UUIDs for partitionsStephen Warren
The MSDOS/MBR partition table includes a 32-bit unique ID, often referred to as the NT disk signature. When combined with a partition number within the table, this can form a unique ID similar in concept to EFI/GPT's partition UUID. Constructing and recording this value in struct partition_meta_info allows MSDOS partitions to be referred to on the kernel command-line using the following syntax: root=PARTUUID=0002dd75-01 Signed-off-by: Stephen Warren <swarren@nvidia.com> Cc: Tejun Heo <tj@kernel.org> Cc: Will Drewry <wad@chromium.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-11-23block: store partition_meta_info.uuid as a stringStephen Warren
This will allow other types of UUID to be stored here, aside from true UUIDs. This also simplifies code that uses this field, since it's usually constructed from a, used as a, or compared to other, strings. Note: A simplistic approach here would be to set uuid_str[36]=0 whenever a /PARTNROFF option was found to be present. However, this modifies the input string, and causes subsequent calls to devt_from_partuuid() not to see the /PARTNROFF option, which causes different results. In order to avoid misleading future maintainers, this parameter is marked const. Signed-off-by: Stephen Warren <swarren@nvidia.com> Cc: Tejun Heo <tj@kernel.org> Cc: Will Drewry <wad@chromium.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-11-19cgroup: rename ->create/post_create/pre_destroy/destroy() to ↵Tejun Heo
->css_alloc/online/offline/free() Rename cgroup_subsys css lifetime related callbacks to better describe what their roles are. Also, update documentation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-10block: use NUMA_NO_NODE instead of -1Ezequiel Garcia
Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com> Modified by me to cover blk_init_queue() as well. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-11-09block: recursive merge requestsShaohua Li
In a workload, thread 1 accesses a, a+2, ..., thread 2 accesses a+1, a+3,.... When the requests are flushed to queue, a and a+1 are merged to (a, a+1), a+2 and a+3 too to (a+2, a+3), but (a, a+1) and (a+2, a+3) aren't merged. If we do recursive merge for such interleave access, some workloads throughput get improvement. A recent worload I'm checking on is swap, below change boostes the throughput around 5% ~ 10%. Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-11-06Merge branch 'cgroup/for-3.7-fixes' into cgroup/for-3.8Tejun Heo
This is to receive device_cgroup fixes so that further device_cgroup changes can be made in cgroup/for-3.8. Signed-off-by: Tejun Heo <tj@kernel.org>
2012-11-06block CFQ: avoid moving request to different queueShaohua Li
request is queued in cfqq->fifo list. Looks it's possible we are moving a request from one cfqq to another in request merge case. In such case, adjusting the fifo list order doesn't make sense and is impossible if we don't iterate the whole fifo list. My test does hit one case the two cfqq are different, but didn't cause kernel crash, maybe it's because fifo list isn't used frequently. Anyway, from the code logic, this is buggy. I thought we can re-enable the recusive merge logic after this is fixed. Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>