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2013-05-14blk-throttle: add throtl_qnode for dispatch fairnessTejun Heo
With flat hierarchy, there's only single level of dispatching happening and fairness beyond that point is the responsibility of the rest of the block layer and driver, which usually works out okay; however, with the planned hierarchy support, service_queue->bio_lists[] can be filled up by bios from a single source. While the limits would still be honored, it'd be very easy to starve IOs from siblings or children. To avoid such starvation, this patch implements throtl_qnode and converts service_queue->bio_lists[] to lists of per-source qnodes which in turn contains the bio's. For example, when a bio is dispatched from a child group, the bio doesn't get queued on ->bio_lists[] directly but it first gets queued on the group's qnode which in turn gets queued on service_queue->queued[]. When dispatching for the upper level, the ->queued[] list is consumed in round-robing order so that the dispatch windows is consumed fairly by all IO sources. There are two ways a bio can come to a throtl_grp - directly queued to the group or dispatched from a child. For the former throtl_grp->qnode_on_self[rw] is used. For the latter, the child's ->qnode_on_parent[rw]. Note that this means that the child which is contributing a bio to its parent should stay pinned until all its bios are dispatched to its grand-parent. This patch moves blkg refcnting from bio add/remove spots to qnode activation/deactivation so that the blkg containing an active qnode is always pinned. As child pins the parent, this is sufficient for keeping the relevant sub-tree pinned while bios are in flight. The starvation issue was spotted by Vivek Goyal. v2: The original patch used the same throtl_grp->qnode_on_self/parent for reads and writes causing RWs to be queued incorrectly if there already are outstanding IOs in the other direction. They should be throtl_grp->qnode_on_self/parent[2] so that READs and WRITEs can use different qnodes. Spotted by Vivek Goyal. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: make throtl_pending_timer_fn() ready for hierarchyTejun Heo
throtl_pending_timer_fn() currently assumes that the parent_sq is the top level one and the bio's dispatched are ready to be issued; however, this assumption will be wrong with proper hierarchy support. This patch makes the following changes to make throtl_pending_timer_fn() ready for hiearchy. * If the parent_sq isn't the top-level one, update the parent throtl_grp's dispatch time and schedule the next dispatch as necessary. If the parent's dispatch time is now, repeat the function for the parent throtl_grp. * If the parent_sq is the top-level one, kick issue work_item as before. * The debug message printed by throtl_log() now prints out the service_queue's nr_queued[] instead of the total nr_queued as the latter becomes uninteresting and misleading with hierarchical dispatch. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: make tg_dispatch_one_bio() ready for hierarchyTejun Heo
tg_dispatch_one_bio() currently assumes that the parent_sq is the top level one and the bio being dispatched is ready to be issued; however, this assumption will be wrong with proper hierarchy support. This patch makes the following changes to make tg_dispatch_on_bio() ready for hiearchy. * throtl_data->nr_queued[] is incremented in blk_throtl_bio() instead of throtl_add_bio_tg() so that throtl_add_bio_tg() can be used to transfer a bio from a child tg to its parent. * tg_dispatch_one_bio() is updated to distinguish whether its parent is another throtl_grp or the throtl_data. If former, the bio is transferred to the parent throtl_grp using throtl_add_bio_tg(). If latter, the bio is ready to be issued and put on the top-level service_queue's bio_lists[] and throtl_data->nr_queued is decremented. As all throtl_grps currently have the top level service_queue as their ->parent_sq, this patch in itself doesn't make any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: make blk_throtl_bio() ready for hierarchyTejun Heo
Currently, blk_throtl_bio() issues the passed in bio directly if it's within limits of its associated tg (throtl_grp). This behavior becomes incorrect with hierarchy support as the bio should be accounted to and throttled by the ancestor throtl_grps too. This patch makes the direct issue path of blk_throtl_bio() to loop until it reaches the top-level service_queue or gets throttled. If the former, the bio can be issued directly; otherwise, it gets queued at the first layer it was above limits. As tg->parent_sq is always the top-level service queue currently, this patch in itself doesn't make any behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: make blk_throtl_drain() ready for hierarchyTejun Heo
The current blk_throtl_drain() assumes that all active throtl_grps are queued on throtl_data->service_queue, which won't be true once hierarchy support is implemented. This patch makes blk_throtl_drain() perform post-order walk of the blkg hierarchy draining each associated throtl_grp, which guarantees that all bios will eventually be pushed to the top-level service_queue in throtl_data. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: dispatch from throtl_pending_timer_fn()Tejun Heo
Currently, blk_throtl_dispatch_work_fn() is responsible for both dispatching bio's from throtl_grp's according to their limits and then issuing the dispatched bios. This patch moves the dispatch part to throtl_pending_timer_fn() so that the work item is kicked iff there are bio's to issue. This is to avoid work item execution at each step when hierarchy support is enabled. bio's will be dispatched towards the top-level service_queue from the timers at each layer and the work item will only be used to issue the bio's which reached the top-level service_queue. While fetching bio's to issue from bio_lists[], blk_throtl_dispatch_work_fn() fetches all READs before WRITEs. While the original code also dispatched READs first, if multiple throtl_grps are dispatched on the same run, WRITEs from throtl_grp which is dispatched first would precede READs from throtl_grps which are dispatched later. While this is a behavior change, given that the previous code already prioritized READs and block layer generally prioritizes and segregates READs from WRITEs, this isn't likely to make any noticeable differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: implement dispatch loopingTejun Heo
throtl_select_dispatch() only dispatches throtl_quantum bios on each invocation. blk_throtl_dispatch_work_fn() in turn depends on throtl_schedule_next_dispatch() scheduling the next dispatch window immediately so that undue delays aren't incurred. This effectively chains multiple dispatch work item executions back-to-back when there are more than throtl_quantum bios to dispatch on a given tick. There is no reason to finish the current work item just to repeat it immediately. This patch makes throtl_schedule_next_dispatch() return %false without doing anything if the current dispatch window is still open and updates blk_throtl_dispatch_work_fn() repeat dispatching after cpu_relax() on %false return. This change will help implementing hierarchy support as dispatching will be done from pending_timer and immediate reschedule of timer function isn't supported and doesn't make much sense. While this patch changes how dispatch behaves when there are more than throtl_quantum bios to dispatch on a single tick, the behavior change is immaterial. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: separate out throtl_service_queue->pending_timer from ↵Tejun Heo
throtl_data->dispatch_work Currently, throtl_data->dispatch_work is a delayed_work item which handles both delayed dispatch and issuing bios. The two tasks will be separated to support proper hierarchy. To prepare for that, this patch separates out the timer into throtl_service_queue->pending_timer from throtl_data->dispatch_work and make the latter a work_struct. * As the timer is now per-service_queue, it's initialized and del_sync'd as its corresponding service_queue is created and destroyed. The timer, when triggered, simply schedules throtl_data->dispathc_work for execution. * throtl_schedule_delayed_work() is renamed to throtl_schedule_pending_timer() and takes @sq and @expires now. * Simiarly, throtl_schedule_next_dispatch() now takes @sq, which should be the parent_sq of the service_queue which just got a new bio or updated. As the parent_sq is always the top-level service_queue now, this doesn't change anything at this point. This patch doesn't introduce any behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: set REQ_THROTTLED from throtl_charge_bio() and gate stats ↵Tejun Heo
update with it With proper hierarchy support, a bio can be dispatched multiple times until it reaches the top-level service_queue and we don't want to update dispatch stats at each step. They are local stats and will be kept local. If recursive stats are necessary, they should be implemented separately and definitely not by updating counters recursively on each dispatch. This patch moves REQ_THROTTLED setting to throtl_charge_bio() and gate stats update with it so that dispatch stats are updated only on the first time the bio is charged to a throtl_grp, which will always be the throtl_grp the bio was originally queued to. This means that REQ_THROTTLED would be set even for bios which don't get throttled. As we don't want bios to leave blk-throtl with the flag set, move REQ_THROTLLED clearing to the end of blk_throtl_bio() and clear if the bio is being issued directly. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: implement sq_to_tg(), sq_to_td() and throtl_log()Tejun Heo
Now that both throtl_data and throtl_grp embed throtl_service_queue, we can unify throtl_log() and throtl_log_tg(). * sq_to_tg() is added. This returns the throtl_grp a service_queue is embedded in. If the service_queue is the top-level one embedded in throtl_data, NULL is returned. * sq_to_td() is added. A service_queue is always associated with a throtl_data. This function finds the associated td and returns it. * throtl_log() is updated to take throtl_service_queue instead of throtl_data. If the service_queue is one embedded in throtl_grp, it prints the same header as throtl_log_tg() did. If it's one embedded in throtl_data, it behaves the same as before. This renders throtl_log_tg() unnecessary. Removed. This change is necessary for hierarchy support as we're gonna be using the same code paths to dispatch bios to intermediate service_queues embedded in throtl_grps and the top-level service_queue embedded in throtl_data. This patch doesn't make any behavior changes. v2: throtl_log() didn't print a space after blkg path. Updated so that it prints a space after throtl_grp path. Spotted by Vivek. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: add throtl_service_queue->parent_sqTejun Heo
To prepare for hierarchy support, this patch adds throtl_service_queue->service_sq which points to the arent service_queue. Currently, for all service_queues embedded in throtl_grps, it points to throtl_data->service_queue. As throtl_data->service_queue doesn't have a parent its parent_sq is set to NULL. There are a number of functions which take both throtl_grp *tg and throtl_service_queue *parent_sq. With this patch, the parent service_queue can be determined from @tg and the @parent_sq arguments are removed. This patch doesn't make any behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: generalize update_disptime optimization in blk_throtl_bio()Tejun Heo
When blk_throtl_bio() wants to queue a bio to a tg (throtl_grp), it avoids invoking tg_update_disptime() and throtl_schedule_next_dispatch() if the tg already has bios queued in that direction. As a new bio is appeneded after the existing ones, it can't change the tg's next dispatch time or the parent's dispatch schedule. This optimization is currently open coded in blk_throtl_bio(). Whether the target biolist was occupied was recorded in a local variable and later used to skip disptime update. This patch moves generalizes it so that throtl_add_bio_tg() sets a new flag THROTL_TG_WAS_EMPTY if the biolist was empty before the new bio was added. tg_update_disptime() clears the flag automatically. blk_throtl_bio() is updated to simply test the flag before updating disptime. This patch doesn't make any functional differences now but will enable using the same optimization for recursive dispatch. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: dispatch to throtl_data->service_queue.bio_lists[]Tejun Heo
throtl_service_queues will eventually form a tree which is anchored at throtl_data->service_queue and queue bios will climb the tree to the top service_queue to be executed. This patch makes the dispatch paths in blk_throtl_dispatch_work_fn() and blk_throtl_drain() to dispatch bios to throtl_data->service_queue.bio_lists[] instead of the on-stack bio_lists. This will keep the final dispatch to the top level service_queue share the same mechanism as dispatches through the rest of the hierarchy. As bio's should be issued in a sleepable context, blk_throtl_dispatch_work_fn() transfers all dispatched bio's from the service_queue bio_lists[] into an onstack one before dropping queue_lock and issuing the bio's. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: move bio_lists[] and friends to throtl_service_queueTejun Heo
throtl_service_queues will eventually form a tree which is anchored at throtl_data->service_queue and queue bios will climb the tree to the top service_queue to be executed. This patch moves bio_lists[] and nr_queued[] from throtl_grp to its service_queue to prepare for that. As currently only the throtl_data->service_queue is in use, this patch just ends up moving throtl_grp->bio_lists[] and ->nr_queued[] to throtl_grp->service_queue.bio_lists[] and ->nr_queued[] without making any functional differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: add throtl_grp->service_queueTejun Heo
Currently, there's single service_queue per queue - throtl_data->service_queue. All active throtl_grp's are queued on the queue and dispatched according to their limits. To support hierarchy, this will be expanded such that active throtl_grp's form a tree anchored at throtl_data->service_queue and chained through each intermediate throtl_grp's service_queue. This patch adds throtl_grp->service_queue to prepare for hierarchy support. The initialization function - throtl_service_queue_init() - is added and replaces the macro initializer. The newly added tg->service_queue isn't used yet. Following patches will do. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: reorganize throtl_service_queue passed around as argumentTejun Heo
throtl_service_queue will be the building block of hierarchy support and will form a tree. This patch updates its usages as arguments to reduce confusion. * When a service queue is used as the parent role - the host of the rbtree - use @parent_sq instead of @sq. * For functions taking both @tg and @parent_sq, reorder them so that the order is (@tg, @parent_sq) not the other way around. This makes the code follow the usual convention of specifying the primary target of the operation as the first argument. This patch doesn't make any functional differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: pass around throtl_service_queue instead of throtl_dataTejun Heo
throtl_service_queue will be used as the basic block to implement hierarchy support. Pass around throtl_service_queue *sq instead of throtl_data *td in the following functions which will be used across multiple levels of hierarchy. * [__]throtl_enqueue/dequeue_tg() * throtl_add_bio_tg() * tg_update_disptime() * throtl_select_dispatch() Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: add backlink pointer from throtl_grp to throtl_dataTejun Heo
Add throtl_grp->td so that the td (throtl_data) a given tg (throtl_grp) belongs to can be determined, and remove @td argument from functions which take both @td and @tg as the former now can be determined from the latter. This generally simplifies the code and removes a number of cases where @td is passed as an argument without being actually used. This will also help hierarchy support implementation. While at it, in multi-line conditions, move the logical operators leading broken lines to the end of the previous line. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: simplify throtl_grp flag handlingTejun Heo
blk-throttle is still using function-defining macros to define flag handling functions, which went out style at least a decade ago. Just define the flag as bitmask and use direct bit operations. This patch doesn't make any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: rename throtl_rb_root to throtl_service_queueTejun Heo
throtl_rb_root will be expanded to cover more roles for hierarchy support. Rename it to throtl_service_queue and make its fields more descriptive. * rb -> pending_tree * left -> first_pending * count -> nr_pending * min_disptime -> first_pending_disptime This patch is purely cosmetic. Signed-off-by: Tejun Heo <tj@kernel.org Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: remove pointless throtl_nr_queued() optimizationsTejun Heo
throtl_nr_queued() is used in several places to avoid performing certain operations when the throtl_data is empty. This usually is useless as those paths usually aren't traveled if there's no bio queued. * throtl_schedule_delayed_work() skips scheduling dispatch work item if @td doesn't have any bios queued; however, the only case it can be called when @td is empty is from tg_set_conf() which isn't something we should be optimizing for. * throtl_schedule_next_dispatch() takes a quick exit if @td is empty; however, right after that it triggers BUG if the service tree is empty. The two conditions are equivalent and it can just test @st->count for the quick exit. * blk_throtl_dispatch_work_fn() skips dispatch if @td is empty. This work function isn't usually invoked when @td is empty. The only possibility is from tg_set_conf() and when it happens the normal dispatching path can handle empty @td fine. No need to add special skip path. This patch removes the above three unnecessary optimizations, which leave throtl_log() call in blk_throtl_dispatch_work_fn() the only user of throtl_nr_queued(). Remove throtl_nr_queued() and open code it in throtl_log(). I don't think we need td->nr_queued[] at all. Maybe we can remove it later. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: relocate throtl_schedule_delayed_work()Tejun Heo
Move throtl_schedule_delayed_work() above its first user so that the forward declaration can be removed. This patch is pure relocaiton. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: collapse throtl_dispatch() into the work functionTejun Heo
blk-throttle is about to go through major restructuring to support hierarchy. Do cosmetic updates in preparation. * s/throtl_data->throtl_work/throtl_data->dispatch_work/ * s/blk_throtl_work()/blk_throtl_dispatch_work_fn()/ * Collapse throtl_dispatch() into blk_throtl_dispatch_work_fn() This patch is purely cosmetic. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: remove deferred config application mechanismTejun Heo
When bps or iops configuration changes, blk-throttle records the new configuration and sets a flag indicating that the config has changed. The flag is checked in the bio dispatch path and applied. This deferred config application was necessary due to limitations in blkcg framework, which haven't existed for quite a while now. This patch removes the deferred config application mechanism and applies new configurations directly from tg_set_conf(), which is simpler. v2: Dropped unnecessary throtl_schedule_delayed_work() call from tg_set_conf() as suggested by Vivek Goyal. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blk-throttle: remove spurious throtl_enqueue_tg() call from ↵Tejun Heo
throtl_select_dispatch() throtl_select_dispatch() calls throtl_enqueue_tg() right after tg_update_disptime(), which always calls the function anyway. The call is, while harmless, unnecessary. Remove it. This patch doesn't introduce any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blkcg: move bulk of blkcg_gq release operations to the RCU callbackTejun Heo
Currently, when the last reference of a blkcg_gq is put, all then release operations sans the actual freeing happen directly in blkg_put(). As blkg_put() may be called under queue_lock, all pd_exit_fn()s may be too. This makes it impossible for pd_exit_fn()s to use del_timer_sync() on timers which grab the queue_lock which is an irq-safe lock due to the deadlock possibility described in the comment on top of del_timer_sync(). This can be easily avoided by perfoming the release operations in the RCU callback instead of directly from blkg_put(). This patch moves the blkcg_gq release operations to the RCU callback. As this leaves __blkg_release() with only call_rcu() invocation, blkg_rcu_free() is renamed to __blkg_release_rcu(), exported and call_rcu() invocation is now done directly from blkg_put() instead of going through __blkg_release() which is removed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blkcg: invoke blkcg_policy->pd_init() after parent is linkedTejun Heo
Currently, when creating a new blkcg_gq, each policy's pd_init_fn() is invoked in blkg_alloc() before the parent is linked. This makes it difficult for policies to perform initializations which are dependent on the parent. This patch moves pd_init_fn() invocations to blkg_create() after the parent blkg is linked where the new blkg is fully initialized. As this means that blkg_free() can't assume that pd's are initialized, pd_exit_fn() invocations are moved to __blkg_release(). This guarantees that pd_exit_fn() is also invoked with fully initialized blkgs with valid parent pointers. This will help implementing hierarchy support in blk-throttle. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blkcg: implement blkg_for_each_descendant_post()Tejun Heo
This will be used by blk-throttle hierarchy support. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blkcg: move blkg_for_each_descendant_pre() to block/blk-cgroup.hTejun Heo
blk-throttle hierarchy support will make use of it. Move blkg_for_each_descendant_pre() from block/blk-cgroup.c to block/blk-cgroup.h. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14blkcg: fix error return path in blkg_create()Tejun Heo
In blkg_create(), after lookup of parent fails, the control jumps to error path with the error code encoded into @blkg. The error path doesn't use @blkg for the return value. It returns ERR_PTR(ret). Make lookup fail path set @ret instead of @blkg. Note that the parent lookup is guaranteed to succeed at that point and the condition check is purely for sanity and triggers WARN when fails. As such, I don't think it's necessary to mark it for -stable. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14block: queue work on power efficient wqViresh Kumar
Block layer uses workqueues for multiple purposes. There is no real dependency of scheduling these on the cpu which scheduled them. On a idle system, it is observed that and idle cpu wakes up many times just to service this work. It would be better if we can schedule it on a cpu which the scheduler believes to be the most appropriate one. This patch replaces normal workqueues with power efficient versions. Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2013-05-08Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block core updates from Jens Axboe: - Major bit is Kents prep work for immutable bio vecs. - Stable candidate fix for a scheduling-while-atomic in the queue bypass operation. - Fix for the hang on exceeded rq->datalen 32-bit unsigned when merging discard bios. - Tejuns changes to convert the writeback thread pool to the generic workqueue mechanism. - Runtime PM framework, SCSI patches exists on top of these in James' tree. - A few random fixes. * 'for-3.10/core' of git://git.kernel.dk/linux-block: (40 commits) relay: move remove_buf_file inside relay_close_buf partitions/efi.c: replace useless kzalloc's by kmalloc's fs/block_dev.c: fix iov_shorten() criteria in blkdev_aio_read() block: fix max discard sectors limit blkcg: fix "scheduling while atomic" in blk_queue_bypass_start Documentation: cfq-iosched: update documentation help for cfq tunables writeback: expose the bdi_wq workqueue writeback: replace custom worker pool implementation with unbound workqueue writeback: remove unused bdi_pending_list aoe: Fix unitialized var usage bio-integrity: Add explicit field for owner of bip_buf block: Add an explicit bio flag for bios that own their bvec block: Add bio_alloc_pages() block: Convert some code to bio_for_each_segment_all() block: Add bio_for_each_segment_all() bounce: Refactor __blk_queue_bounce to not use bi_io_vec raid1: use bio_copy_data() pktcdvd: Use bio_reset() in disabled code to kill bi_idx usage pktcdvd: use bio_copy_data() block: Add bio_copy_data() ...
2013-05-07aio: don't include aio.h in sched.hKent Overstreet
Faster kernel compiles by way of fewer unnecessary includes. [akpm@linux-foundation.org: fix fallout] [akpm@linux-foundation.org: fix build] Signed-off-by: Kent Overstreet <koverstreet@google.com> Cc: Zach Brown <zab@redhat.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jens Axboe <axboe@kernel.dk> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Benjamin LaHaise <bcrl@kvack.org> Reviewed-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-02Merge tag 'virtio-next-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull virtio & lguest updates from Rusty Russell: "Lots of virtio work which wasn't quite ready for last merge window. Plus I dived into lguest again, reworking the pagetable code so we can move the switcher page: our fixmaps sometimes take more than 2MB now..." Ugh. Annoying conflicts with the tcm_vhost -> vhost_scsi rename. Hopefully correctly resolved. * tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (57 commits) caif_virtio: Remove bouncing email addresses lguest: improve code readability in lg_cpu_start. virtio-net: fill only rx queues which are being used lguest: map Switcher below fixmap. lguest: cache last cpu we ran on. lguest: map Switcher text whenever we allocate a new pagetable. lguest: don't share Switcher PTE pages between guests. lguest: expost switcher_pages array (as lg_switcher_pages). lguest: extract shadow PTE walking / allocating. lguest: make check_gpte et. al return bool. lguest: assume Switcher text is a single page. lguest: rename switcher_page to switcher_pages. lguest: remove RESERVE_MEM constant. lguest: check vaddr not pgd for Switcher protection. lguest: prepare to make SWITCHER_ADDR a variable. virtio: console: replace EMFILE with EBUSY for already-open port virtio-scsi: reset virtqueue affinity when doing cpu hotplug virtio-scsi: introduce multiqueue support virtio-scsi: push vq lock/unlock into virtscsi_vq_done virtio-scsi: pass struct virtio_scsi to virtqueue completion function ...
2013-04-30partitions/efi.c: replace useless kzalloc's by kmalloc'sPhilippe De Muyter
In alloc_read_gpt_entries and alloc_read_gpt_header, the kzalloc'ated zones are either totally overwritten by the following read_lba call, or freed. As kmalloc is cheaper than kzalloc, use kmalloc. Signed-off-by: Philippe De Muyter <phdm@macqel.be> Cc: Matt Domsch <Matt_Domsch@dell.com> Cc: Panagiotis Issaris <takis@issaris.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-04-29Merge branch 'for-3.10' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: - Fixes and a lot of cleanups. Locking cleanup is finally complete. cgroup_mutex is no longer exposed to individual controlelrs which used to cause nasty deadlock issues. Li fixed and cleaned up quite a bit including long standing ones like racy cgroup_path(). - device cgroup now supports proper hierarchy thanks to Aristeu. - perf_event cgroup now supports proper hierarchy. - A new mount option "__DEVEL__sane_behavior" is added. As indicated by the name, this option is to be used for development only at this point and generates a warning message when used. Unfortunately, cgroup interface currently has too many brekages and inconsistencies to implement a consistent and unified hierarchy on top. The new flag is used to collect the behavior changes which are necessary to implement consistent unified hierarchy. It's likely that this flag won't be used verbatim when it becomes ready but will be enabled implicitly along with unified hierarchy. The option currently disables some of broken behaviors in cgroup core and also .use_hierarchy switch in memcg (will be routed through -mm), which can be used to make very unusual hierarchy where nesting is partially honored. It will also be used to implement hierarchy support for blk-throttle which would be impossible otherwise without introducing a full separate set of control knobs. This is essentially versioning of interface which isn't very nice but at this point I can't see any other options which would allow keeping the interface the same while moving towards hierarchy behavior which is at least somewhat sane. The planned unified hierarchy is likely to require some level of adaptation from userland anyway, so I think it'd be best to take the chance and update the interface such that it's supportable in the long term. Maintaining the existing interface does complicate cgroup core but shouldn't put too much strain on individual controllers and I think it'd be manageable for the foreseeable future. Maybe we'll be able to drop it in a decade. Fix up conflicts (including a semantic one adding a new #include to ppc that was uncovered by header the file changes) as per Tejun. * 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (45 commits) cpuset: fix compile warning when CONFIG_SMP=n cpuset: fix cpu hotplug vs rebuild_sched_domains() race cpuset: use rebuild_sched_domains() in cpuset_hotplug_workfn() cgroup: restore the call to eventfd->poll() cgroup: fix use-after-free when umounting cgroupfs cgroup: fix broken file xattrs devcg: remove parent_cgroup. memcg: force use_hierarchy if sane_behavior cgroup: remove cgrp->top_cgroup cgroup: introduce sane_behavior mount option move cgroupfs_root to include/linux/cgroup.h cgroup: convert cgroupfs_root flag bits to masks and add CGRP_ prefix cgroup: make cgroup_path() not print double slashes Revert "cgroup: remove bind() method from cgroup_subsys." perf: make perf_event cgroup hierarchical cgroup: implement cgroup_is_descendant() cgroup: make sure parent won't be destroyed before its children cgroup: remove bind() method from cgroup_subsys. devcg: remove broken_hierarchy tag cgroup: remove cgroup_lock_is_held() ...
2013-04-29Merge tag 'driver-core-3.10-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core update from Greg Kroah-Hartman: "Here's the merge request for the driver core tree for 3.10-rc1 It's pretty small, just a number of driver core and sysfs updates and fixes, all of which have been in linux-next for a while now. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>" Fixed conflict in kernel/rtmutex-tester.c, the locking tree had a better fix for the same sysfs file mode problem. * tag 'driver-core-3.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: PM / Runtime: Idle devices asynchronously after probe|release driver core: handle user namespaces properly with the uid/gid devtmpfs change driver core: devtmpfs: fix compile failure with CONFIG_UIDGID_STRICT_TYPE_CHECKS devtmpfs: add base.h include driver core: add uid and gid to devtmpfs sysfs: check if one entry has been removed before freeing sysfs: fix crash_notes_size build warning sysfs: fix use after free in case of concurrent read/write and readdir rtmutex-tester: fix mode of sysfs files Documentation: Add ABI entry for crash_notes and crash_notes_size sysfs: Add crash_notes_size to export percpu note size driver core: platform_device.h: fix checkpatch errors and warnings driver core: platform.c: fix checkpatch errors and warnings driver core: warn that platform_driver_probe can not use deferred probing sysfs: use atomic_inc_unless_negative in sysfs_get_active base: core: WARN() about bogus permissions on device attributes device: separate all subsys mutexes
2013-04-18Revert "block: add missing block_bio_complete() tracepoint"Linus Torvalds
This reverts commit 3a366e614d0837d9fc23f78cdb1a1186ebc3387f. Wanlong Gao reports that it causes a kernel panic on his machine several minutes after boot. Reverting it removes the panic. Jens says: "It's not quite clear why that is yet, so I think we should just revert the commit for 3.9 final (which I'm assuming is pretty close). The wifi is crap at the LSF hotel, so sending this email instead of queueing up a revert and pull request." Reported-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> Requested-by: Jens Axboe <axboe@kernel.dk> Cc: Tejun Heo <tj@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-14Merge 3.9-rc7 into driver-core-nextGreg Kroah-Hartman
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-04-11driver core: handle user namespaces properly with the uid/gid devtmpfs changeGreg Kroah-Hartman
Now that devtmpfs is caring about uid/gid, we need to use the correct internal types so users who have USER_NS enabled will have things work properly for them. Thanks to Eric for pointing this out, and the patch review. Reported-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Cc: Ming Lei <ming.lei@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-04-09blkcg: fix "scheduling while atomic" in blk_queue_bypass_startJun'ichi Nomura
Since 749fefe677 in v3.7 ("block: lift the initial queue bypass mode on blk_register_queue() instead of blk_init_allocated_queue()"), the following warning appears when multipath is used with CONFIG_PREEMPT=y. This patch moves blk_queue_bypass_start() before radix_tree_preload() to avoid the sleeping call while preemption is disabled. BUG: scheduling while atomic: multipath/2460/0x00000002 1 lock held by multipath/2460: #0: (&md->type_lock){......}, at: [<ffffffffa019fb05>] dm_lock_md_type+0x17/0x19 [dm_mod] Modules linked in: ... Pid: 2460, comm: multipath Tainted: G W 3.7.0-rc2 #1 Call Trace: [<ffffffff810723ae>] __schedule_bug+0x6a/0x78 [<ffffffff81428ba2>] __schedule+0xb4/0x5e0 [<ffffffff814291e6>] schedule+0x64/0x66 [<ffffffff8142773a>] schedule_timeout+0x39/0xf8 [<ffffffff8108ad5f>] ? put_lock_stats+0xe/0x29 [<ffffffff8108ae30>] ? lock_release_holdtime+0xb6/0xbb [<ffffffff814289e3>] wait_for_common+0x9d/0xee [<ffffffff8107526c>] ? try_to_wake_up+0x206/0x206 [<ffffffff810c0eb8>] ? kfree_call_rcu+0x1c/0x1c [<ffffffff81428aec>] wait_for_completion+0x1d/0x1f [<ffffffff810611f9>] wait_rcu_gp+0x5d/0x7a [<ffffffff81061216>] ? wait_rcu_gp+0x7a/0x7a [<ffffffff8106fb18>] ? complete+0x21/0x53 [<ffffffff810c0556>] synchronize_rcu+0x1e/0x20 [<ffffffff811dd903>] blk_queue_bypass_start+0x5d/0x62 [<ffffffff811ee109>] blkcg_activate_policy+0x73/0x270 [<ffffffff81130521>] ? kmem_cache_alloc_node_trace+0xc7/0x108 [<ffffffff811f04b3>] cfq_init_queue+0x80/0x28e [<ffffffffa01a1600>] ? dm_blk_ioctl+0xa7/0xa7 [dm_mod] [<ffffffff811d8c41>] elevator_init+0xe1/0x115 [<ffffffff811e229f>] ? blk_queue_make_request+0x54/0x59 [<ffffffff811dd743>] blk_init_allocated_queue+0x8c/0x9e [<ffffffffa019ffcd>] dm_setup_md_queue+0x36/0xaa [dm_mod] [<ffffffffa01a60e6>] table_load+0x1bd/0x2c8 [dm_mod] [<ffffffffa01a7026>] ctl_ioctl+0x1d6/0x236 [dm_mod] [<ffffffffa01a5f29>] ? table_clear+0xaa/0xaa [dm_mod] [<ffffffffa01a7099>] dm_ctl_ioctl+0x13/0x17 [dm_mod] [<ffffffff811479fc>] do_vfs_ioctl+0x3fb/0x441 [<ffffffff811b643c>] ? file_has_perm+0x8a/0x99 [<ffffffff81147aa0>] sys_ioctl+0x5e/0x82 [<ffffffff812010be>] ? trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff814310d9>] system_call_fastpath+0x16/0x1b Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: Alasdair G Kergon <agk@redhat.com> Cc: stable@kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-04-08driver core: add uid and gid to devtmpfsKay Sievers
Some drivers want to tell userspace what uid and gid should be used for their device nodes, so allow that information to percolate through the driver core to userspace in order to make this happen. This means that some systems (i.e. Android and friends) will not need to even run a udev-like daemon for their device node manager and can just rely in devtmpfs fully, reducing their footprint even more. Signed-off-by: Kay Sievers <kay@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-04-08Revert "loop: cleanup partitions when detaching loop device"Jens Axboe
This reverts commit 8761a3dc1f07b163414e2215a2cadbb4cfe2a107. There are situations where the destruction path is called with the bdev->bd_mutex already held, which then deadlocks in loop_clr_fd(). The normal partition cleanup does a trylock() on the mutex, but it'd be nice to have a more bullet proof method in loop. So punt this more involved fix to the next merge window, and just back out this buggy fix for now. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-04-03block: avoid using uninitialized value in from queue_var_storeArnd Bergmann
As found by gcc-4.8, the QUEUE_SYSFS_BIT_FNS macro creates functions that use a value generated by queue_var_store independent of whether that value was set or not. block/blk-sysfs.c: In function 'queue_store_nonrot': block/blk-sysfs.c:244:385: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized] Unlike most other such warnings, this one is not a false positive, writing any non-number string into the sysfs files indeed has an undefined result, rather than returning an error. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-04-02Merge branch 'writeback-workqueue' of ↵Jens Axboe
git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq into for-3.10/core Tejun writes: ----- This is the pull request for the earlier patchset[1] with the same name. It's only three patches (the first one was committed to workqueue tree) but the merge strategy is a bit involved due to the dependencies. * Because the conversion needs features from wq/for-3.10, block/for-3.10/core is based on rc3, and wq/for-3.10 has conflicts with rc3, I pulled mainline (rc5) into wq/for-3.10 to prevent those workqueue conflicts from flaring up in block tree. * Resolving the issue that Jan and Dave raised about debugging requires arch-wide changes. The patchset is being worked on[2] but it'll have to go through -mm after these changes show up in -next, and not included in this pull request. The three commits are located in the following git branch. git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git writeback-workqueue Pulling it into block/for-3.10/core produces a conflict in drivers/md/raid5.c between the following two commits. e3620a3ad5 ("MD RAID5: Avoid accessing gendisk or queue structs when not available") 2f6db2a707 ("raid5: use bio_reset()") The conflict is trivial - one removes an "if ()" conditional while the other removes "rbi->bi_next = NULL" right above it. We just need to remove both. The merged branch is available at git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git block-test-merge so that you can use it for verification. The test merge commit has proper merge description. While these changes are a bit of pain to route, they make code simpler and even have, while minute, measureable performance gain[3] even on a workload which isn't particularly favorable to showing the benefits of this conversion. ---- Fixed up the conflict. Conflicts: drivers/md/raid5.c Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-03-24Merge branch 'for-jens' of http://evilpiepirate.org/git/linux-bcache into ↵Jens Axboe
for-3.10/core This contains Kents prep work for the immutable bio_vecs.
2013-03-23block: Add bio_end_sector()Kent Overstreet
Just a little convenience macro - main reason to add it now is preparing for immutable bio vecs, it'll reduce the size of the patch that puts bi_sector/bi_size/bi_idx into a struct bvec_iter. Signed-off-by: Kent Overstreet <koverstreet@google.com> CC: Jens Axboe <axboe@kernel.dk> CC: Lars Ellenberg <drbd-dev@lists.linbit.com> CC: Jiri Kosina <jkosina@suse.cz> CC: Alasdair Kergon <agk@redhat.com> CC: dm-devel@redhat.com CC: Neil Brown <neilb@suse.de> CC: Martin Schwidefsky <schwidefsky@de.ibm.com> CC: Heiko Carstens <heiko.carstens@de.ibm.com> CC: linux-s390@vger.kernel.org CC: Chris Mason <chris.mason@fusionio.com> CC: Steven Whitehouse <swhiteho@redhat.com> Acked-by: Steven Whitehouse <swhiteho@redhat.com>
2013-03-23block: Refactor blk_update_request()Kent Overstreet
Converts it to use bio_advance(), simplifying it quite a bit in the process. Note that req_bio_endio() now always calls bio_advance() - which means it always loops over the biovec, not just on partial completions. Don't expect it to affect performance, but worth noting. Tested it by forcing partial updates, and dumping before and after on various bio/bvec fields when doing a partial update. Signed-off-by: Kent Overstreet <koverstreet@google.com> CC: Jens Axboe <axboe@kernel.dk>
2013-03-22block: implement runtime pm strategyLin Ming
When a request is added: If device is suspended or is suspending and the request is not a PM request, resume the device. When the last request finishes: Call pm_runtime_mark_last_busy(). When pick a request: If device is resuming/suspending, then only PM request is allowed to go. The idea and API is designed by Alan Stern and described here: http://marc.info/?l=linux-scsi&m=133727953625963&w=2 Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-03-22block: add runtime pm helpersLin Ming
Add runtime pm helper functions: void blk_pm_runtime_init(struct request_queue *q, struct device *dev) - Initialization function for drivers to call. int blk_pre_runtime_suspend(struct request_queue *q) - If any requests are in the queue, mark last busy and return -EBUSY. Otherwise set q->rpm_status to RPM_SUSPENDING and return 0. void blk_post_runtime_suspend(struct request_queue *q, int err) - If the suspend succeeded then set q->rpm_status to RPM_SUSPENDED. Otherwise set it to RPM_ACTIVE and mark last busy. void blk_pre_runtime_resume(struct request_queue *q) - Set q->rpm_status to RPM_RESUMING. void blk_post_runtime_resume(struct request_queue *q, int err) - If the resume succeeded then set q->rpm_status to RPM_ACTIVE and call __blk_run_queue, then mark last busy and autosuspend. Otherwise set q->rpm_status to RPM_SUSPENDED. The idea and API is designed by Alan Stern and described here: http://marc.info/?l=linux-scsi&m=133727953625963&w=2 Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Jens Axboe <axboe@kernel.dk>