linux-stable.git/include/linux/blk-cgroup.h, branch v5.6.2

blk-cgroup: remove blkcg_drain_queue

2019-12-12T16:26:55+00:00

Since blk_drain_queue had already been removed, so this function
is not needed anymore.

Signed-off-by: Guoqing Jiang 
Signed-off-by: Jens Axboe

blk-cgroup: cgroup_rstat_updated() shouldn't be called on cgroup1

2019-11-18T15:40:41+00:00

Currently, cgroup rstat is supported only on cgroup2 hierarchy and
rstat functions shouldn't be called on cgroup1 cgroups.  While
converting blk-cgroup core statistics to rstat, f73316482977
("blk-cgroup: reimplement basic IO stats using cgroup rstat")
accidentally ended up calling cgroup_rstat_updated() on cgroup1
cgroups causing crashes.

Longer term, we probably should add cgroup1 support to rstat but for
now let's mask the call directly.

Fixes: f73316482977 ("blk-cgroup: reimplement basic IO stats using cgroup rstat")
Tested-by: Faiz Abbas 
Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

blk-cgroup: separate out blkg_rwstat under CONFIG_BLK_CGROUP_RWSTAT

2019-11-07T19:28:13+00:00

blkg_rwstat is now only used by bfq-iosched and blk-throtl when on
cgroup1.  Let's move it into its own files and gate it behind a config
option.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

blk-cgroup: reimplement basic IO stats using cgroup rstat

2019-11-07T19:28:13+00:00

blk-cgroup has been using blkg_rwstat to track basic IO stats.
Unfortunately, reading recursive stats scales badly as itinvolves
walking all descendants.  On systems with a huge number of cgroups
(dead or alive), this can lead to substantial CPU cost when reading IO
stats.

This patch reimplements basic IO stats using cgroup rstat which uses
more memory but makes recursive stat reading O(# descendants which
have been active since last reading) instead of O(# descendants).

* blk-cgroup core no longer uses sync/async stats.  Introduce new stat
  enums - BLKG_IOSTAT_{READ|WRITE|DISCARD}.

* Add blkg_iostat[_set] which encapsulates byte and io stats, last
  values for propagation delta calculation and u64_stats_sync for
  correctness on 32bit archs.

* Update the new percpu stat counters directly and implement
  blkcg_rstat_flush() to implement propagation.

* blkg_print_stat() can now bring the stats up to date by calling
  cgroup_rstat_flush() and print them instead of directly summing up
  all descendants.

* It now allocates 96 bytes per cpu.  It used to be 40 bytes.

Signed-off-by: Tejun Heo 
Cc: Dan Schatzberg 
Cc: Daniel Xu 
Signed-off-by: Jens Axboe

blk-cgroup: remove now unused blkg_print_stat_{bytes|ios}_recursive()

2019-11-07T19:28:13+00:00

These don't have users anymore.  Remove them.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

blkcg: separate blkcg_conf_get_disk() out of blkg_conf_prep()

2019-08-29T03:17:04+00:00

Separate out blkcg_conf_get_disk() so that it can be used by blkcg
policy interface file input parsers before the policy is actually
enabled.  This doesn't introduce any functional changes.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

blkcg: pass @q and @blkcg into blkcg_pol_alloc_pd_fn()

2019-08-29T03:17:01+00:00

Instead of @node, pass in @q and @blkcg so that the alloc function has
more context.  This doesn't cause any behavior change and will be used
by io.weight implementation.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

block: Fix spelling in the header above blkg_lookup()

2019-08-05T03:41:29+00:00

See also commit 8f4236d9008b ("block: remove QUEUE_FLAG_BYPASS and ->bypass") # v5.0.

Cc: Christoph Hellwig 
Cc: Hannes Reinecke 
Signed-off-by: Bart Van Assche 
Signed-off-by: Jens Axboe

blkcg: allow blkcg_policy->pd_stat() to print non-debug info too

2019-07-16T16:06:39+00:00

Currently, ->pd_stat() is called only when moduleparam
blkcg_debug_stats is set which prevents it from printing non-debug
policy-specific statistics.  Let's move debug testing down so that
->pd_stat() can print non-debug stat too.  This patch doesn't cause
any visible behavior change.

Signed-off-by: Tejun Heo 
Cc: Josef Bacik 
Signed-off-by: Jens Axboe

blkcg: implement REQ_CGROUP_PUNT

2019-07-10T15:00:57+00:00

When a shared kthread needs to issue a bio for a cgroup, doing so
synchronously can lead to priority inversions as the kthread can be
trapped waiting for that cgroup.  This patch implements
REQ_CGROUP_PUNT flag which makes submit_bio() punt the actual issuing
to a dedicated per-blkcg work item to avoid such priority inversions.

This will be used to fix priority inversions in btrfs compression and
should be generally useful as we grow filesystem support for
comprehensive IO control.

Cc: Chris Mason 
Reviewed-by: Josef Bacik 
Reviewed-by: Jan Kara 
Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe