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| * | | | | writeback: add dirty_throttle_control->wb_completionsTejun Heo2015-06-021-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | wb->completions measures the wb's proportional write bandwidth in global_wb_domain and thus naturally tied to the wb_domain. This patch adds dirty_throttle_control->wb_completions which is initialized to wb->completions by GDTC_INIT() and updates __wb_dirty_limits() to use it instead of dereferencing wb->completions directly. This will allow dirty_throttle_control to represent different wb_domains and the matching wb completions. This patch doesn't introduce any behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: add dirty_throttle_control->pos_ratioTejun Heo2015-06-021-15/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | wb_position_ratio() is used to calculate pos_ratio, which is used for two purposes. wb_update_dirty_ratelimit() uses it to adjust wb->[balanced_]dirty_ratelimit gradually and balance_dirty_pages() to immediately adjust dirty_ratelimit right before applying it to determine pause duration. While wb_update_dirty_ratelimit() is separately rate limited from balance_dirty_pages(), on the run where the ratelimit is updated, we end up calculating pos_ratio twice with the same parameters. This patch adds dirty_throttle_control->pos_ratio. balance_dirty_pages() calculates it once per run and wb_update_dirty_ratelimit() uses the value stored in dirty_throttle_control. This removes the duplicate calculation and also will help implementing memcg wb_domain. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make __wb_calc_thresh() take dirty_throttle_controlTejun Heo2015-06-021-7/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | wb_calc_thresh() calculates wb_thresh by scaling thresh according to the wb's portion in the system-wide write bandwidth. cgroup writeback support would need to calculate wb_thresh against memcg domain too. This patch renames wb_calc_thresh() to __wb_calc_thresh() and makes it take dirty_throttle_control so that the function can later be updated to calculate against different domains according to dirty_throttle_control. wb_calc_thresh() is now a thin wrapper around __wb_calc_thresh(). v2: The original version was incorrectly scaling dtc->dirty instead of dtc->thresh. This was due to the extremely confusing function and variable names. Added a rename patch and fixed this one. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: add dirty_throttle_control->wb_bg_threshTejun Heo2015-06-021-16/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | wb_bg_thresh is currently treated as a second-class citizen. It's only used when BDI_CAP_STRICTLIMIT is set and balance_dirty_pages() doesn't calculate it unless the cap is set. When the cap is set, the calculated value is not passed around but instead recalculated whenever it's used. wb_position_ratio() calculates it by scaling wb_thresh proportional to bg_thresh / thresh. wb_update_dirty_ratelimit() uses wb_dirty_limit() on bg_thresh, which should generally lead to a similar result as the proportional scaling but can also be way off in the presence of max/min_ratio settings. Avoiding wb_bg_thresh calculation saves us one u64 multiplication and divsion when BDI_CAP_STRICTLIMIT is not set. Given that balance_dirty_pages() is already ratelimited, this doesn't justify the incurred extra complexity. This patch adds wb_bg_thresh to dirty_throttle_control and makes wb_dirty_limits() always calculate it and updates the users to use the pre-calculated value. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: consolidate dirty throttle parameters into dirty_throttle_controlTejun Heo2015-06-021-111/+101
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dirty throttling implemented in balance_dirty_pages() and its subroutines makes use of a number of parameters which are passed around individually. This renders these functions somewhat unwieldy and makes it difficult to add or change the involved parameters. Also some functions use different or conflicting naming schemes for the same parameters making the code confusing to follow. This patch consolidates the main parameters into struct dirty_throttle_control so that they can be passed around easily and adding new paramters isn't painful. This also unifies how a given parameter is named and accessed. The drawback of using this type of control structure rather than explicit paramters is that it isn't immediately obvious which function accesses and modifies what; however, it's fairly clear that the benefits outweigh in this case. GDTC_INIT() macro is provided to ease initializing dirty_throttle_control for the global_wb_domain and balance_dirty_pages() uses a separate pointer to point to its global dirty_throttle_control. This is to make it uniform with memcg domain handling which will be added later. This patch doesn't introduce any behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: move global_dirty_limit into wb_domainTejun Heo2015-06-021-23/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is a part of the series to define wb_domain which represents a domain that wb's (bdi_writeback's) belong to and are measured against each other in. This will enable IO backpressure propagation for cgroup writeback. global_dirty_limit exists to regulate the global dirty threshold which is a property of the wb_domain. This patch moves hard_dirty_limit, dirty_lock, and update_time into wb_domain. This is pure reorganization and doesn't introduce any behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement wb_domainTejun Heo2015-06-021-45/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dirtyable memory is distributed to a wb (bdi_writeback) according to the relative bandwidth the wb is writing out in the whole system. This distribution is global - each wb is measured against all other wb's and gets the proportinately sized portion of the memory in the whole system. For cgroup writeback, the amount of dirtyable memory is scoped by memcg and thus each wb would need to be measured and controlled in its memcg. IOW, a wb will belong to two writeback domains - the global and memcg domains. Currently, what constitutes the global writeback domain are scattered across a number of global states. This patch starts collecting them into struct wb_domain. * fprop_global which serves as the basis for proportional bandwidth measurement and its period timer are moved into struct wb_domain. * global_wb_domain hosts the states for the global domain. * While at it, flatten wb_writeout_fraction() into its callers. This thin wrapper doesn't provide any actual benefits while getting in the way. This is pure reorganization and doesn't introduce any behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: reorganize [__]wb_update_bandwidth()Tejun Heo2015-06-021-23/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __wb_update_bandwidth() is called from two places - fs/fs-writeback.c::balance_dirty_pages() and mm/page-writeback.c::wb_writeback(). The latter updates only the write bandwidth while the former also deals with the dirty ratelimit. The two callsites are distinguished by whether @thresh parameter is zero or not, which is cryptic. In addition, the two files define their own different versions of wb_update_bandwidth() on top of __wb_update_bandwidth(), which is confusing to say the least. This patch cleans up [__]wb_update_bandwidth() in the following ways. * __wb_update_bandwidth() now takes explicit @update_ratelimit parameter to gate dirty ratelimit handling. * mm/page-writeback.c::wb_update_bandwidth() is flattened into its caller - balance_dirty_pages(). * fs/fs-writeback.c::wb_update_bandwidth() is moved to mm/page-writeback.c and __wb_update_bandwidth() is made static. * While at it, add a lockdep assertion to __wb_update_bandwidth(). Except for the lockdep addition, this is pure reorganization and doesn't introduce any behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: clean up wb_dirty_limit()Tejun Heo2015-06-022-18/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The function name wb_dirty_limit(), its argument @dirty and the local variable @wb_dirty are mortally confusing given that the function calculates per-wb threshold value not dirty pages, especially given that @dirty and @wb_dirty are used elsewhere for dirty pages. Let's rename the function to wb_calc_thresh() and wb_dirty to wb_thresh. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | memcg: make mem_cgroup_read_{stat|event}() iterate possible cpus instead of ↵Tejun Heo2015-06-021-49/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | online cpu_possible_mask represents the CPUs which are actually possible during that boot instance. For systems which don't support CPU hotplug, this will match cpu_online_mask exactly in most cases. Even for systems which support CPU hotplug, the number of possible CPU slots is highly unlikely to diverge greatly from the number of online CPUs. The only cases where the difference between possible and online caused problems were when the boot code failed to initialize the possible mask and left it fully set at NR_CPUS - 1. As such, most per-cpu constructs allocate for all possible CPUs and often iterate over the possibles, which also has the benefit of avoiding the blocking CPU hotplug synchronization. memcg open codes per-cpu stat counting for mem_cgroup_read_stat() and mem_cgroup_read_events(), which iterates over online CPUs and handles CPU hotplug operations explicitly. This complexity doesn't actually buy anything. Switch to iterating over the possibles and drop the explicit CPU hotplug handling. Eventually, we want to convert memcg to use percpu_counter instead of its own custom implementation which also benefits from quick access w/o summing for cases where larger error margin is acceptable. This will allow mem_cgroup_read_stat() to be called from non-sleepable contexts which will be used by cgroup writeback. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Michal Hocko <mhocko@suse.cz> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement bdi_wait_for_completion()Tejun Heo2015-06-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the completion of a wb_writeback_work can be waited upon by setting its ->done to a struct completion and waiting on it; however, for cgroup writeback support, it's necessary to issue multiple work items to multiple bdi_writebacks and wait for the completion of all. This patch implements wb_completion which can wait for multiple work items and replaces the struct completion with it. It can be defined using DEFINE_WB_COMPLETION_ONSTACK(), used for multiple work items and waited for by wb_wait_for_completion(). Nobody currently issues multiple work items and this patch doesn't introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make bdi_start_background_writeback() take bdi_writeback instead ↵Tejun Heo2015-06-021-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | of backing_dev_info bdi_start_background_writeback() currently takes @bdi and kicks the root wb (bdi_writeback). In preparation for cgroup writeback support, make it take wb instead. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make writeback_in_progress() take bdi_writeback instead of ↵Tejun Heo2015-06-021-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | backing_dev_info writeback_in_progress() currently takes @bdi and returns whether writeback is in progress on its root wb (bdi_writeback). In preparation for cgroup writeback support, make it take wb instead. While at it, make it an inline function. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make laptop_mode_timer_fn() handle multiple bdi_writeback'sTejun Heo2015-06-021-3/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For cgroup writeback support, all bdi-wide operations should be distributed to all its wb's (bdi_writeback's). This patch updates laptop_mode_timer_fn() so that it invokes wb_start_writeback() on all wb's rather than just the root one. As the intent is writing out all dirty data, there's no reason to split the number of pages to write. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: remove bdi_start_writeback()Tejun Heo2015-06-021-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | bdi_start_writeback() is a thin wrapper on top of __wb_start_writeback() which is used only by laptop_mode_timer_fn(). This patches removes bdi_start_writeback(), renames __wb_start_writeback() to wb_start_writeback() and makes laptop_mode_timer_fn() use it instead. This doesn't cause any functional difference and will ease making laptop_mode_timer_fn() cgroup writeback aware. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make bdi->min/max_ratio handling cgroup writeback awareTejun Heo2015-06-021-4/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | bdi->min/max_ratio are user-configurable per-bdi knobs which regulate dirty limit of each bdi. For cgroup writeback, they need to be further distributed across wb's (bdi_writeback's) belonging to the configured bdi. This patch introduces wb_min_max_ratio() which distributes bdi->min/max_ratio according to a wb's proportion in the total active bandwidth of its bdi. v2: Update wb_min_max_ratio() to fix a bug where both min and max were assigned the min value and avoid calculations when possible. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make bdi_has_dirty_io() take multiple bdi_writeback's into accountTejun Heo2015-06-022-8/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | bdi_has_dirty_io() used to only reflect whether the root wb (bdi_writeback) has dirty inodes. For cgroup writeback support, it needs to take all active wb's into account. If any wb on the bdi has dirty inodes, bdi_has_dirty_io() should return true. To achieve that, as inode_wb_list_{move|del}_locked() now keep track of the dirty state transition of each wb, the number of dirty wbs can be counted in the bdi; however, bdi is already aggregating wb->avg_write_bandwidth which can easily be guaranteed to be > 0 when there are any dirty inodes by ensuring wb->avg_write_bandwidth can't dip below 1. bdi_has_dirty_io() can simply test whether bdi->tot_write_bandwidth is zero or not. While this bumps the value of wb->avg_write_bandwidth to one when it used to be zero, this shouldn't cause any meaningful behavior difference. bdi_has_dirty_io() is made an inline function which tests whether ->tot_write_bandwidth is non-zero. Also, WARN_ON_ONCE()'s on its value are added to inode_wb_list_{move|del}_locked(). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement backing_dev_info->tot_write_bandwidthTejun Heo2015-06-021-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup writeback support needs to keep track of the sum of avg_write_bandwidth of all wb's (bdi_writeback's) with dirty inodes to distribute write workload. This patch adds bdi->tot_write_bandwidth and updates inode_wb_list_move_locked(), inode_wb_list_del_locked() and wb_update_write_bandwidth() to adjust it as wb's gain and lose dirty inodes and its avg_write_bandwidth gets updated. As the update events are not synchronized with each other, bdi->tot_write_bandwidth is an atomic_long_t. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement WB_has_dirty_io wb_state flagTejun Heo2015-06-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, wb_has_dirty_io() determines whether a wb (bdi_writeback) has any dirty inode by testing all three IO lists on each invocation without actively keeping track. For cgroup writeback support, a single bdi will host multiple wb's each of which will host dirty inodes separately and we'll need to make bdi_has_dirty_io(), which currently only represents the root wb, aggregate has_dirty_io from all member wb's, which requires tracking transitions in has_dirty_io state on each wb. This patch introduces inode_wb_list_{move|del}_locked() to consolidate IO list operations leaving queue_io() the only other function which directly manipulates IO lists (via move_expired_inodes()). All three functions are updated to call wb_io_lists_[de]populated() which keep track of whether the wb has dirty inodes or not and record it using the new WB_has_dirty_io flag. inode_wb_list_moved_locked()'s return value indicates whether the wb had no dirty inodes before. mark_inode_dirty() is restructured so that the return value of inode_wb_list_move_locked() can be used for deciding whether to wake up the wb. While at it, change {bdi|wb}_has_dirty_io()'s return values to bool. These functions were returning 0 and 1 before. Also, add a comment explaining the synchronization of wb_state flags. v2: Updated to accommodate b_dirty_time. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement and use inode_congested()Tejun Heo2015-06-023-8/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In several places, bdi_congested() and its wrappers are used to determine whether more IOs should be issued. With cgroup writeback support, this question can't be answered solely based on the bdi (backing_dev_info). It's dependent on whether the filesystem and bdi support cgroup writeback and the blkcg the inode is associated with. This patch implements inode_congested() and its wrappers which take @inode and determines the congestion state considering cgroup writeback. The new functions replace bdi_*congested() calls in places where the query is about specific inode and task. There are several filesystem users which also fit this criteria but they should be updated when each filesystem implements cgroup writeback support. v2: Now that a given inode is associated with only one wb, congestion state can be determined independent from the asking task. Drop @task. Spotted by Vivek. Also, converted to take @inode instead of @mapping and renamed to inode_congested(). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make congestion functions per bdi_writebackTejun Heo2015-06-021-11/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, all congestion functions take bdi (backing_dev_info) and always operate on the root wb (bdi->wb) and the congestion state from the block layer is propagated only for the root blkcg. This patch introduces {set|clear}_wb_congested() and wb_congested() which take a bdi_writeback_congested and bdi_writeback respectively. The bdi counteparts are now wrappers invoking the wb based functions on @bdi->wb. While converting clear_bdi_congested() to clear_wb_congested(), the local variable declaration order between @wqh and @bit is swapped for cosmetic reason. This patch just adds the new wb based functions. The following patches will apply them. v2: Updated for bdi_writeback_congested. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: let balance_dirty_pages() work on the matching cgroup bdi_writebackTejun Heo2015-06-021-5/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, balance_dirty_pages() always work on bdi->wb. This patch updates it to work on the wb (bdi_writeback) matching memcg and blkcg of the current task as that's what the inode is being dirtied against. balance_dirty_pages_ratelimited() now pins the current wb and passes it to balance_dirty_pages(). As no filesystem has FS_CGROUP_WRITEBACK yet, this doesn't lead to visible behavior differences. v2: Updated for per-inode wb association. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: attribute stats to the matching per-cgroup bdi_writebackTejun Heo2015-06-021-9/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Until now, all WB_* stats were accounted against the root wb (bdi_writeback), now that multiple wb (bdi_writeback) support is in place, let's attributes the stats to the respective per-cgroup wb's. As no filesystem has FS_CGROUP_WRITEBACK yet, this doesn't lead to visible behavior differences. v2: Updated for per-inode wb association. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make backing_dev_info host cgroup-specific bdi_writebacksTejun Heo2015-06-023-4/+423
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For the planned cgroup writeback support, on each bdi (backing_dev_info), each memcg will be served by a separate wb (bdi_writeback). This patch updates bdi so that a bdi can host multiple wbs (bdi_writebacks). On the default hierarchy, blkcg implicitly enables memcg. This allows using memcg's page ownership for attributing writeback IOs, and every memcg - blkcg combination can be served by its own wb by assigning a dedicated wb to each memcg. This means that there may be multiple wb's of a bdi mapped to the same blkcg. As congested state is per blkcg - bdi combination, those wb's should share the same congested state. This is achieved by tracking congested state via bdi_writeback_congested structs which are keyed by blkcg. bdi->wb remains unchanged and will keep serving the root cgroup. cgwb's (cgroup wb's) for non-root cgroups are created on-demand or looked up while dirtying an inode according to the memcg of the page being dirtied or current task. Each cgwb is indexed on bdi->cgwb_tree by its memcg id. Once an inode is associated with its wb, it can be retrieved using inode_to_wb(). Currently, none of the filesystems has FS_CGROUP_WRITEBACK and all pages will keep being associated with bdi->wb. v3: inode_attach_wb() in account_page_dirtied() moved inside mapping_cap_account_dirty() block where it's known to be !NULL. Also, an unnecessary NULL check before kfree() removed. Both detected by the kbuild bot. v2: Updated so that wb association is per inode and wb is per memcg rather than blkcg. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: kbuild test robot <fengguang.wu@intel.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | bdi: separate out congested state into a separate structTejun Heo2015-06-021-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, a wb's (bdi_writeback) congestion state is carried in its ->state field; however, cgroup writeback support will require multiple wb's sharing the same congestion state. This patch separates out congestion state into its own struct - struct bdi_writeback_congested. A new field wb field, wb_congested, points to its associated congested struct. The default wb, bdi->wb, always points to bdi->wb_congested. While this patch adds a layer of indirection, it doesn't introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: add @gfp to wb_init()Tejun Heo2015-06-021-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | wb_init() currently always uses GFP_KERNEL but the planned cgroup writeback support needs using other allocation masks. Add @gfp to wb_init(). This patch doesn't introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | bdi: make inode_to_bdi() inlineTejun Heo2015-06-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that bdi definitions are moved to backing-dev-defs.h, backing-dev.h can include blkdev.h and inline inode_to_bdi() without worrying about introducing circular include dependency. The function gets called from hot paths and fairly trivial. This patch makes inode_to_bdi() and sb_is_blkdev_sb() that the function calls inline. blockdev_superblock and noop_backing_dev_info are EXPORT_GPL'd to allow the inline functions to be used from modules. While at it, make sb_is_blkdev_sb() return bool instead of int. v2: Fixed typo in description as suggested by Jan. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: separate out include/linux/backing-dev-defs.hTejun Heo2015-06-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the planned cgroup writeback support, backing-dev related declarations will be more widely used across block and cgroup; unfortunately, including backing-dev.h from include/linux/blkdev.h makes cyclic include dependency quite likely. This patch separates out backing-dev-defs.h which only has the essential definitions and updates blkdev.h to include it. c files which need access to more backing-dev details now include backing-dev.h directly. This takes backing-dev.h off the common include dependency chain making it a lot easier to use it across block and cgroup. v2: fs/fat build failure fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: reorganize mm/backing-dev.cTejun Heo2015-06-021-87/+87
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move wb_shutdown(), bdi_register(), bdi_register_dev(), bdi_prune_sb(), bdi_remove_from_list() and bdi_unregister() so that init / exit functions are grouped together. This will make updating init / exit paths for cgroup writeback support easier. This is pure source file reorganization. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: move backing_dev_info->wb_lock and ->worklist into bdi_writebackTejun Heo2015-06-021-31/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback) and the role of the separation is unclear. For cgroup support for writeback IOs, a bdi will be updated to host multiple wb's where each wb serves writeback IOs of a different cgroup on the bdi. To achieve that, a wb should carry all states necessary for servicing writeback IOs for a cgroup independently. This patch moves bdi->wb_lock and ->worklist into wb. * The lock protects bdi->worklist and bdi->wb.dwork scheduling. While moving, rename it to wb->work_lock as wb->wb_lock is confusing. Also, move wb->dwork downwards so that it's colocated with the new ->work_lock and ->work_list fields. * bdi_writeback_workfn() -> wb_workfn() bdi_wakeup_thread_delayed(bdi) -> wb_wakeup_delayed(wb) bdi_wakeup_thread(bdi) -> wb_wakeup(wb) bdi_queue_work(bdi, ...) -> wb_queue_work(wb, ...) __bdi_start_writeback(bdi, ...) -> __wb_start_writeback(wb, ...) get_next_work_item(bdi) -> get_next_work_item(wb) * bdi_wb_shutdown() is renamed to wb_shutdown() and now takes @wb. The function contained parts which belong to the containing bdi rather than the wb itself - testing cap_writeback_dirty and bdi_remove_from_list() invocation. Those are moved to bdi_unregister(). * bdi_wb_{init|exit}() are renamed to wb_{init|exit}(). Initializations of the moved bdi->wb_lock and ->work_list are relocated from bdi_init() to wb_init(). * As there's still only one bdi_writeback per backing_dev_info, all uses of bdi->state are mechanically replaced with bdi->wb.state introducing no behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: s/bdi/wb/ in mm/page-writeback.cTejun Heo2015-06-021-136/+134
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Writeback operations will now be per wb (bdi_writeback) instead of bdi. Replace the relevant bdi references in symbol names and comments with wb. This patch is purely cosmetic and doesn't make any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: move bandwidth related fields from backing_dev_info into ↵Tejun Heo2015-06-022-155/+152
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | bdi_writeback Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback) and the role of the separation is unclear. For cgroup support for writeback IOs, a bdi will be updated to host multiple wb's where each wb serves writeback IOs of a different cgroup on the bdi. To achieve that, a wb should carry all states necessary for servicing writeback IOs for a cgroup independently. This patch moves bandwidth related fields from backing_dev_info into bdi_writeback. * The moved fields are: bw_time_stamp, dirtied_stamp, written_stamp, write_bandwidth, avg_write_bandwidth, dirty_ratelimit, balanced_dirty_ratelimit, completions and dirty_exceeded. * writeback_chunk_size() and over_bground_thresh() now take @wb instead of @bdi. * bdi_writeout_fraction(bdi, ...) -> wb_writeout_fraction(wb, ...) bdi_dirty_limit(bdi, ...) -> wb_dirty_limit(wb, ...) bdi_position_ration(bdi, ...) -> wb_position_ratio(wb, ...) bdi_update_writebandwidth(bdi, ...) -> wb_update_write_bandwidth(wb, ...) [__]bdi_update_bandwidth(bdi, ...) -> [__]wb_update_bandwidth(wb, ...) bdi_{max|min}_pause(bdi, ...) -> wb_{max|min}_pause(wb, ...) bdi_dirty_limits(bdi, ...) -> wb_dirty_limits(wb, ...) * Init/exits of the relocated fields are moved to bdi_wb_init/exit() respectively. Note that explicit zeroing is dropped in the process as wb's are cleared in entirety anyway. * As there's still only one bdi_writeback per backing_dev_info, all uses of bdi->stat[] are mechanically replaced with bdi->wb.stat[] introducing no behavior changes. v2: Typo in description fixed as suggested by Jan. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: move backing_dev_info->bdi_stat[] into bdi_writebackTejun Heo2015-06-022-51/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback) and the role of the separation is unclear. For cgroup support for writeback IOs, a bdi will be updated to host multiple wb's where each wb serves writeback IOs of a different cgroup on the bdi. To achieve that, a wb should carry all states necessary for servicing writeback IOs for a cgroup independently. This patch moves bdi->bdi_stat[] into wb. * enum bdi_stat_item is renamed to wb_stat_item and the prefix of all enums is changed from BDI_ to WB_. * BDI_STAT_BATCH() -> WB_STAT_BATCH() * [__]{add|inc|dec|sum}_wb_stat(bdi, ...) -> [__]{add|inc}_wb_stat(wb, ...) * bdi_stat[_error]() -> wb_stat[_error]() * bdi_writeout_inc() -> wb_writeout_inc() * stat init is moved to bdi_wb_init() and bdi_wb_exit() is added and frees stat. * As there's still only one bdi_writeback per backing_dev_info, all uses of bdi->stat[] are mechanically replaced with bdi->wb.stat[] introducing no behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: move backing_dev_info->state into bdi_writebackTejun Heo2015-06-021-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback) and the role of the separation is unclear. For cgroup support for writeback IOs, a bdi will be updated to host multiple wb's where each wb serves writeback IOs of a different cgroup on the bdi. To achieve that, a wb should carry all states necessary for servicing writeback IOs for a cgroup independently. This patch moves bdi->state into wb. * enum bdi_state is renamed to wb_state and the prefix of all enums is changed from BDI_ to WB_. * Explicit zeroing of bdi->state is removed without adding zeoring of wb->state as the whole data structure is zeroed on init anyway. * As there's still only one bdi_writeback per backing_dev_info, all uses of bdi->state are mechanically replaced with bdi->wb.state introducing no behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: drbd-dev@lists.linbit.com Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | memcg: implement mem_cgroup_css_from_page()Tejun Heo2015-06-021-0/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement mem_cgroup_css_from_page() which returns the cgroup_subsys_state of the memcg associated with a given page on the default hierarchy. This will be used by cgroup writeback support. This function assumes that page->mem_cgroup association doesn't change until the page is released, which is true on the default hierarchy as long as replace_page_cache_page() is not used. As the only user of replace_page_cache_page() is FUSE which won't support cgroup writeback for the time being, this works for now, and replace_page_cache_page() will soon be updated so that the invariant actually holds. Note that the RCU protected page->mem_cgroup access is consistent with other usages across memcg but ultimately incorrect. These unlocked accesses are missing required barriers. page->mem_cgroup should be made an RCU pointer and updated and accessed using RCU operations. v4: Instead of triggering WARN, return the root css on the traditional hierarchies. This makes the function a lot easier to deal with especially as there's no light way to synchronize against hierarchy rebinding. v3: s/mem_cgroup_migrate()/mem_cgroup_css_from_page()/ v2: Trigger WARN if the function is used on the traditional hierarchies and add comment about the assumed invariant. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | memcg: add mem_cgroup_root_cssTejun Heo2015-06-021-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add global mem_cgroup_root_css which points to the root memcg css. This will be used by cgroup writeback support. If memcg is disabled, it's defined as ERR_PTR(-EINVAL). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> aCc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | memcg: add per cgroup dirty page accountingGreg Thelen2015-06-026-27/+111
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When modifying PG_Dirty on cached file pages, update the new MEM_CGROUP_STAT_DIRTY counter. This is done in the same places where global NR_FILE_DIRTY is managed. The new memcg stat is visible in the per memcg memory.stat cgroupfs file. The most recent past attempt at this was http://thread.gmane.org/gmane.linux.kernel.cgroups/8632 The new accounting supports future efforts to add per cgroup dirty page throttling and writeback. It also helps an administrator break down a container's memory usage and provides evidence to understand memcg oom kills (the new dirty count is included in memcg oom kill messages). The ability to move page accounting between memcg (memory.move_charge_at_immigrate) makes this accounting more complicated than the global counter. The existing mem_cgroup_{begin,end}_page_stat() lock is used to serialize move accounting with stat updates. Typical update operation: memcg = mem_cgroup_begin_page_stat(page) if (TestSetPageDirty()) { [...] mem_cgroup_update_page_stat(memcg) } mem_cgroup_end_page_stat(memcg) Summary of mem_cgroup_end_page_stat() overhead: - Without CONFIG_MEMCG it's a no-op - With CONFIG_MEMCG and no inter memcg task movement, it's just rcu_read_lock() - With CONFIG_MEMCG and inter memcg task movement, it's rcu_read_lock() + spin_lock_irqsave() A memcg parameter is added to several routines because their callers now grab mem_cgroup_begin_page_stat() which returns the memcg later needed by for mem_cgroup_update_page_stat(). Because mem_cgroup_begin_page_stat() may disable interrupts, some adjustments are needed: - move __mark_inode_dirty() from __set_page_dirty() to its caller. __mark_inode_dirty() locking does not want interrupts disabled. - use spin_lock_irqsave(tree_lock) rather than spin_lock_irq() in __delete_from_page_cache(), replace_page_cache_page(), invalidate_complete_page2(), and __remove_mapping(). text data bss dec hex filename 8925147 1774832 1785856 12485835 be84cb vmlinux-!CONFIG_MEMCG-before 8925339 1774832 1785856 12486027 be858b vmlinux-!CONFIG_MEMCG-after +192 text bytes 8965977 1784992 1785856 12536825 bf4bf9 vmlinux-CONFIG_MEMCG-before 8966750 1784992 1785856 12537598 bf4efe vmlinux-CONFIG_MEMCG-after +773 text bytes Performance tests run on v4.0-rc1-36-g4f671fe2f952. Lower is better for all metrics, they're all wall clock or cycle counts. The read and write fault benchmarks just measure fault time, they do not include I/O time. * CONFIG_MEMCG not set: baseline patched kbuild 1m25.030000(+-0.088% 3 samples) 1m25.426667(+-0.120% 3 samples) dd write 100 MiB 0.859211561 +-15.10% 0.874162885 +-15.03% dd write 200 MiB 1.670653105 +-17.87% 1.669384764 +-11.99% dd write 1000 MiB 8.434691190 +-14.15% 8.474733215 +-14.77% read fault cycles 254.0(+-0.000% 10 samples) 253.0(+-0.000% 10 samples) write fault cycles 2021.2(+-3.070% 10 samples) 1984.5(+-1.036% 10 samples) * CONFIG_MEMCG=y root_memcg: baseline patched kbuild 1m25.716667(+-0.105% 3 samples) 1m25.686667(+-0.153% 3 samples) dd write 100 MiB 0.855650830 +-14.90% 0.887557919 +-14.90% dd write 200 MiB 1.688322953 +-12.72% 1.667682724 +-13.33% dd write 1000 MiB 8.418601605 +-14.30% 8.673532299 +-15.00% read fault cycles 266.0(+-0.000% 10 samples) 266.0(+-0.000% 10 samples) write fault cycles 2051.7(+-1.349% 10 samples) 2049.6(+-1.686% 10 samples) * CONFIG_MEMCG=y non-root_memcg: baseline patched kbuild 1m26.120000(+-0.273% 3 samples) 1m25.763333(+-0.127% 3 samples) dd write 100 MiB 0.861723964 +-15.25% 0.818129350 +-14.82% dd write 200 MiB 1.669887569 +-13.30% 1.698645885 +-13.27% dd write 1000 MiB 8.383191730 +-14.65% 8.351742280 +-14.52% read fault cycles 265.7(+-0.172% 10 samples) 267.0(+-0.000% 10 samples) write fault cycles 2070.6(+-1.512% 10 samples) 2084.4(+-2.148% 10 samples) As expected anon page faults are not affected by this patch. tj: Updated to apply on top of the recent cancel_dirty_page() changes. Signed-off-by: Sha Zhengju <handai.szj@gmail.com> Signed-off-by: Greg Thelen <gthelen@google.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | page_writeback: revive cancel_dirty_page() in a restricted formTejun Heo2015-06-022-10/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cancel_dirty_page() had some issues and b9ea25152e56 ("page_writeback: clean up mess around cancel_dirty_page()") replaced it with account_page_cleaned() which makes the caller responsible for clearing the dirty bit; unfortunately, the planned changes for cgroup writeback support requires synchronization between dirty bit manipulation and stat updates. While we can open-code such synchronization in each account_page_cleaned() callsite, that's gonna be unnecessarily awkward and verbose. This patch revives cancel_dirty_page() but in a more restricted form. All it does is TestClearPageDirty() followed by account_page_cleaned() invocation if the page was dirty. This helper covers all account_page_cleaned() usages except for __delete_from_page_cache() which is a special case anyway and left alone. As this leaves no module user for account_page_cleaned(), EXPORT_SYMBOL() is dropped from it. This patch just revives cancel_dirty_page() as a trivial wrapper to replace equivalent usages and doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Jens Axboe <axboe@fb.com>
* | | | | | Merge branch 'for-4.2/core' of git://git.kernel.dk/linux-blockLinus Torvalds2015-06-251-1/+1
|\| | | | | | |/ / / / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull core block IO update from Jens Axboe: "Nothing really major in here, mostly a collection of smaller optimizations and cleanups, mixed with various fixes. In more detail, this contains: - Addition of policy specific data to blkcg for block cgroups. From Arianna Avanzini. - Various cleanups around command types from Christoph. - Cleanup of the suspend block I/O path from Christoph. - Plugging updates from Shaohua and Jeff Moyer, for blk-mq. - Eliminating atomic inc/dec of both remaining IO count and reference count in a bio. From me. - Fixes for SG gap and chunk size support for data-less (discards) IO, so we can merge these better. From me. - Small restructuring of blk-mq shared tag support, freeing drivers from iterating hardware queues. From Keith Busch. - A few cfq-iosched tweaks, from Tahsin Erdogan and me. Makes the IOPS mode the default for non-rotational storage" * 'for-4.2/core' of git://git.kernel.dk/linux-block: (35 commits) cfq-iosched: fix other locations where blkcg_to_cfqgd() can return NULL cfq-iosched: fix sysfs oops when attempting to read unconfigured weights cfq-iosched: move group scheduling functions under ifdef cfq-iosched: fix the setting of IOPS mode on SSDs blktrace: Add blktrace.c to BLOCK LAYER in MAINTAINERS file block, cgroup: implement policy-specific per-blkcg data block: Make CFQ default to IOPS mode on SSDs block: add blk_set_queue_dying() to blkdev.h blk-mq: Shared tag enhancements block: don't honor chunk sizes for data-less IO block: only honor SG gap prevention for merges that contain data block: fix returnvar.cocci warnings block, dm: don't copy bios for request clones block: remove management of bi_remaining when restoring original bi_end_io block: replace trylock with mutex_lock in blkdev_reread_part() block: export blkdev_reread_part() and __blkdev_reread_part() suspend: simplify block I/O handling block: collapse bio bit space block: remove unused BIO_RW_BLOCK and BIO_EOF flags block: remove BIO_EOPNOTSUPP ...
| * | | | suspend: simplify block I/O handlingChristoph Hellwig2015-05-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Stop abusing struct page functionality and the swap end_io handler, and instead add a modified version of the blk-lib.c bio_batch helpers. Also move the block I/O code into swap.c as they are directly tied into each other. Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Pavel Machek <pavel@ucw.cz> Tested-by: Ming Lin <mlin@kernel.org> Acked-by: Pavel Machek <pavel@ucw.cz> Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net> Signed-off-by: Jens Axboe <axboe@fb.com>
* | | | | Merge branch 'akpm' (patches from Andrew)Linus Torvalds2015-06-2433-871/+1009
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge first patchbomb from Andrew Morton: - a few misc things - ocfs2 udpates - kernel/watchdog.c feature work (took ages to get right) - most of MM. A few tricky bits are held up and probably won't make 4.2. * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (91 commits) mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc() mm, thp: respect MPOL_PREFERRED policy with non-local node tmpfs: truncate prealloc blocks past i_size mm/memory hotplug: print the last vmemmap region at the end of hot add memory mm/mmap.c: optimization of do_mmap_pgoff function mm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scan mm: kmemleak: avoid deadlock on the kmemleak object insertion error path mm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup() mm: kmemleak: fix delete_object_*() race when called on the same memory block mm: kmemleak: allow safe memory scanning during kmemleak disabling memcg: convert mem_cgroup->under_oom from atomic_t to int memcg: remove unused mem_cgroup->oom_wakeups frontswap: allow multiple backends x86, mirror: x86 enabling - find mirrored memory ranges mm/memblock: allocate boot time data structures from mirrored memory mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute mm: do not ignore mapping_gfp_mask in page cache allocation paths mm/cma.c: fix typos in comments mm/oom_kill.c: print points as unsigned int mm/hugetlb: handle races in alloc_huge_page and hugetlb_reserve_pages ...
| * | | | | mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc()Larry Finger2015-06-242-5/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Beginning at commit d52d3997f843 ("ipv6: Create percpu rt6_info"), the following INFO splat is logged: =============================== [ INFO: suspicious RCU usage. ] 4.1.0-rc7-next-20150612 #1 Not tainted ------------------------------- kernel/sched/core.c:7318 Illegal context switch in RCU-bh read-side critical section! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 3 locks held by systemd/1: #0: (rtnl_mutex){+.+.+.}, at: [<ffffffff815f0c8f>] rtnetlink_rcv+0x1f/0x40 #1: (rcu_read_lock_bh){......}, at: [<ffffffff816a34e2>] ipv6_add_addr+0x62/0x540 #2: (addrconf_hash_lock){+...+.}, at: [<ffffffff816a3604>] ipv6_add_addr+0x184/0x540 stack backtrace: CPU: 0 PID: 1 Comm: systemd Not tainted 4.1.0-rc7-next-20150612 #1 Hardware name: TOSHIBA TECRA A50-A/TECRA A50-A, BIOS Version 4.20 04/17/2014 Call Trace: dump_stack+0x4c/0x6e lockdep_rcu_suspicious+0xe7/0x120 ___might_sleep+0x1d5/0x1f0 __might_sleep+0x4d/0x90 kmem_cache_alloc+0x47/0x250 create_object+0x39/0x2e0 kmemleak_alloc_percpu+0x61/0xe0 pcpu_alloc+0x370/0x630 Additional backtrace lines are truncated. In addition, the above splat is followed by several "BUG: sleeping function called from invalid context at mm/slub.c:1268" outputs. As suggested by Martin KaFai Lau, these are the clue to the fix. Routine kmemleak_alloc_percpu() always uses GFP_KERNEL for its allocations, whereas it should follow the gfp from its callers. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net> Cc: Martin KaFai Lau <kafai@fb.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: <stable@vger.kernel.org> [3.18+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | mm, thp: respect MPOL_PREFERRED policy with non-local nodeVlastimil Babka2015-06-241-16/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since commit 077fcf116c8c ("mm/thp: allocate transparent hugepages on local node"), we handle THP allocations on page fault in a special way - for non-interleave memory policies, the allocation is only attempted on the node local to the current CPU, if the policy's nodemask allows the node. This is motivated by the assumption that THP benefits cannot offset the cost of remote accesses, so it's better to fallback to base pages on the local node (which might still be available, while huge pages are not due to fragmentation) than to allocate huge pages on a remote node. The nodemask check prevents us from violating e.g. MPOL_BIND policies where the local node is not among the allowed nodes. However, the current implementation can still give surprising results for the MPOL_PREFERRED policy when the preferred node is different than the current CPU's local node. In such case we should honor the preferred node and not use the local node, which is what this patch does. If hugepage allocation on the preferred node fails, we fall back to base pages and don't try other nodes, with the same motivation as is done for the local node hugepage allocations. The patch also moves the MPOL_INTERLEAVE check around to simplify the hugepage specific test. The difference can be demonstrated using in-tree transhuge-stress test on the following 2-node machine where half memory on one node was occupied to show the difference. > numactl --hardware available: 2 nodes (0-1) node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 24 25 26 27 28 29 30 31 32 33 34 35 node 0 size: 7878 MB node 0 free: 3623 MB node 1 cpus: 12 13 14 15 16 17 18 19 20 21 22 23 36 37 38 39 40 41 42 43 44 45 46 47 node 1 size: 8045 MB node 1 free: 7818 MB node distances: node 0 1 0: 10 21 1: 21 10 Before the patch: > numactl -p0 -C0 ./transhuge-stress transhuge-stress: 2.197 s/loop, 0.276 ms/page, 7249.168 MiB/s 7962 succeed, 0 failed, 1786 different pages > numactl -p0 -C12 ./transhuge-stress transhuge-stress: 2.962 s/loop, 0.372 ms/page, 5376.172 MiB/s 7962 succeed, 0 failed, 3873 different pages Number of successful THP allocations corresponds to free memory on node 0 in the first case and node 1 in the second case, i.e. -p parameter is ignored and cpu binding "wins". After the patch: > numactl -p0 -C0 ./transhuge-stress transhuge-stress: 2.183 s/loop, 0.274 ms/page, 7295.516 MiB/s 7962 succeed, 0 failed, 1760 different pages > numactl -p0 -C12 ./transhuge-stress transhuge-stress: 2.878 s/loop, 0.361 ms/page, 5533.638 MiB/s 7962 succeed, 0 failed, 1750 different pages > numactl -p1 -C0 ./transhuge-stress transhuge-stress: 4.628 s/loop, 0.581 ms/page, 3440.893 MiB/s 7962 succeed, 0 failed, 3918 different pages The -p parameter is respected regardless of cpu binding. > numactl -C0 ./transhuge-stress transhuge-stress: 2.202 s/loop, 0.277 ms/page, 7230.003 MiB/s 7962 succeed, 0 failed, 1750 different pages > numactl -C12 ./transhuge-stress transhuge-stress: 3.020 s/loop, 0.379 ms/page, 5273.324 MiB/s 7962 succeed, 0 failed, 3916 different pages Without -p parameter, hugepage restriction to CPU-local node works as before. Fixes: 077fcf116c8c ("mm/thp: allocate transparent hugepages on local node") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | tmpfs: truncate prealloc blocks past i_sizeJosef Bacik2015-06-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | One of the rocksdb people noticed that when you do something like this fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, 10M) pwrite(fd, buf, 5M, 0) ftruncate(5M) on tmpfs, the file would still take up 10M: which led to super fun issues because we were getting ENOSPC before we thought we should be getting ENOSPC. This patch fixes the problem, and mirrors what all the other fs'es do (and was agreed to be the correct behaviour at LSF). I tested it locally to make sure it worked properly with the following xfs_io -f -c "falloc -k 0 10M" -c "pwrite 0 5M" -c "truncate 5M" file Without the patch we have "Blocks: 20480", with the patch we have the correct value of "Blocks: 10240". Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | mm/memory hotplug: print the last vmemmap region at the end of hot add memoryZhu Guihua2015-06-241-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When hot add two nodes continuously, we found the vmemmap region info is a bit messed. The last region of node 2 is printed when node 3 hot added, like the following: Initmem setup node 2 [mem 0x0000000000000000-0xffffffffffffffff] On node 2 totalpages: 0 Built 2 zonelists in Node order, mobility grouping on. Total pages: 16090539 Policy zone: Normal init_memory_mapping: [mem 0x40000000000-0x407ffffffff] [mem 0x40000000000-0x407ffffffff] page 1G [ffffea1000000000-ffffea10001fffff] PMD -> [ffff8a077d800000-ffff8a077d9fffff] on node 2 [ffffea1000200000-ffffea10003fffff] PMD -> [ffff8a077de00000-ffff8a077dffffff] on node 2 ... [ffffea101f600000-ffffea101f9fffff] PMD -> [ffff8a074ac00000-ffff8a074affffff] on node 2 [ffffea101fa00000-ffffea101fdfffff] PMD -> [ffff8a074a800000-ffff8a074abfffff] on node 2 Initmem setup node 3 [mem 0x0000000000000000-0xffffffffffffffff] On node 3 totalpages: 0 Built 3 zonelists in Node order, mobility grouping on. Total pages: 16090539 Policy zone: Normal init_memory_mapping: [mem 0x60000000000-0x607ffffffff] [mem 0x60000000000-0x607ffffffff] page 1G [ffffea101fe00000-ffffea101fffffff] PMD -> [ffff8a074a400000-ffff8a074a5fffff] on node 2 <=== node 2 ??? [ffffea1800000000-ffffea18001fffff] PMD -> [ffff8a074a600000-ffff8a074a7fffff] on node 3 [ffffea1800200000-ffffea18005fffff] PMD -> [ffff8a074a000000-ffff8a074a3fffff] on node 3 [ffffea1800600000-ffffea18009fffff] PMD -> [ffff8a0749c00000-ffff8a0749ffffff] on node 3 ... The cause is the last region was missed at the and of hot add memory, and p_start, p_end, node_start were not reset, so when hot add memory to a new node, it will consider they are not contiguous blocks and print the previous one. So we print the last vmemmap region at the end of hot add memory to avoid the confusion. Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | mm/mmap.c: optimization of do_mmap_pgoff functionPiotr Kwapulinski2015-06-241-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The simple check for zero length memory mapping may be performed earlier. So that in case of zero length memory mapping some unnecessary code is not executed at all. It does not make the code less readable and saves some CPU cycles. Signed-off-by: Piotr Kwapulinski <kwapulinski.piotr@gmail.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | mm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scanCatalin Marinas2015-06-241-34/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kmemleak memory scanning uses finer grained object->lock spinlocks primarily to avoid races with the memory block freeing. However, the pointer lookup in the rb tree requires the kmemleak_lock to be held. This is currently done in the find_and_get_object() function for each pointer-like location read during scanning. While this allows a low latency on kmemleak_*() callbacks on other CPUs, the memory scanning is slower. This patch moves the kmemleak_lock outside the scan_block() loop, acquiring/releasing it only once per scanned memory block. The allow_resched logic is moved outside scan_block() and a new scan_large_block() function is implemented which splits large blocks in MAX_SCAN_SIZE chunks with cond_resched() calls in-between. A redundant (object->flags & OBJECT_NO_SCAN) check is also removed from scan_object(). With this patch, the kmemleak scanning performance is significantly improved: at least 50% with lock debugging disabled and over an order of magnitude with lock proving enabled (on an arm64 system). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | mm: kmemleak: avoid deadlock on the kmemleak object insertion error pathCatalin Marinas2015-06-241-4/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While very unlikely (usually kmemleak or sl*b bug), the create_object() function in mm/kmemleak.c may fail to insert a newly allocated object into the rb tree. When this happens, kmemleak disables itself and prints additional information about the object already found in the rb tree. Such printing is done with the parent->lock acquired, however the kmemleak_lock is already held. This is a potential race with the scanning thread which acquires object->lock and kmemleak_lock in a This patch removes the locking around the 'parent' object information printing. Such object cannot be freed or removed from object_tree_root and object_list since kmemleak_lock is already held. There is a very small risk that some of the object data is being modified on another CPU but the only downside is inconsistent information printing. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | mm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup()Catalin Marinas2015-06-241-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kmemleak_do_cleanup() work thread already waits for the kmemleak_scan thread to finish via kthread_stop(). Waiting in kthread_stop() while scan_mutex is held may lead to deadlock if kmemleak_scan_thread() also waits to acquire for scan_mutex. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | mm: kmemleak: fix delete_object_*() race when called on the same memory blockCatalin Marinas2015-06-241-13/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Calling delete_object_*() on the same pointer is not a standard use case (unless there is a bug in the code calling kmemleak_free()). However, during kmemleak disabling (error or user triggered via /sys), there is a potential race between kmemleak_free() calls on a CPU and __kmemleak_do_cleanup() on a different CPU. The current delete_object_*() implementation first performs a look-up holding kmemleak_lock, increments the object->use_count and then re-acquires kmemleak_lock to remove the object from object_tree_root and object_list. This patch simplifies the delete_object_*() mechanism to both look up and remove an object from the object_tree_root and object_list atomically (guarded by kmemleak_lock). This allows safe concurrent calls to delete_object_*() on the same pointer without additional locking for synchronising the kmemleak_free_enabled flag. A side effect is a slight improvement in the delete_object_*() performance by avoiding acquiring kmemleak_lock twice and incrementing/decrementing object->use_count. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>