diff options
| author | Johannes Weiner <hannes@cmpxchg.org> | 2018-12-06 09:06:47 -0500 |
|---|---|---|
| committer | Michael Bestas <mkbestas@lineageos.org> | 2022-04-19 00:51:40 +0300 |
| commit | 8be9674bf85ce2d4c6c44e0d89b0510e5ae1e7d4 (patch) | |
| tree | ddffe7729bd5b02e23086892fc383c5cfd76d7a8 | |
| parent | 689be33ae1a6d75922183aa0de1f0a8a46a941bf (diff) | |
FROMLIST: kernel: cgroup: add poll file operation
Cgroup has a standardized poll/notification mechanism for waking all
pollers on all fds when a filesystem node changes. To allow polling for
custom events, add a .poll callback that can override the default.
This is in preparation for pollable cgroup pressure files which have
per-fd trigger configurations.
Link: http://lkml.kernel.org/r/20190124211518.244221-3-surenb@google.com
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
(in linux-next: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=c88177361203be291a49956b6c9d5ec164ea24b2)
Conflicts:
include/linux/cgroup-defs.h
kernel/cgroup.c
1. made changes in kernel/cgroup.c instead of kernel/cgroup/cgroup.c
2. replaced __poll_t with unsigned int
Bug: 111308141
Test: modified lmkd to use PSI and tested using lmkd_unit_test
Change-Id: Ie3d914197d1f150e1d83c6206865566a7cbff1b4
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
| -rw-r--r-- | include/linux/cgroup-defs.h | 4 | ||||
| -rw-r--r-- | kernel/cgroup.c | 12 |
2 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index e5ecb29d1fb1..2475cc15b50a 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -28,6 +28,7 @@ struct kernfs_node; struct kernfs_ops; struct kernfs_open_file; struct seq_file; +struct poll_table_struct; #define MAX_CGROUP_TYPE_NAMELEN 32 #define MAX_CGROUP_ROOT_NAMELEN 64 @@ -431,6 +432,9 @@ struct cftype { ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off); + unsigned int (*poll)(struct kernfs_open_file *of, + struct poll_table_struct *pt); + #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lock_class_key lockdep_key; #endif diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 377755875623..3ebed4a84625 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -3529,6 +3529,16 @@ static ssize_t cgroup_file_write(struct kernfs_open_file *of, char *buf, return ret ?: nbytes; } +static unsigned int cgroup_file_poll(struct kernfs_open_file *of, poll_table *pt) +{ + struct cftype *cft = of->kn->priv; + + if (cft->poll) + return cft->poll(of, pt); + + return kernfs_generic_poll(of, pt); +} + static void *cgroup_seqfile_start(struct seq_file *seq, loff_t *ppos) { return seq_cft(seq)->seq_start(seq, ppos); @@ -3567,6 +3577,7 @@ static struct kernfs_ops cgroup_kf_single_ops = { .open = cgroup_file_open, .release = cgroup_file_release, .write = cgroup_file_write, + .poll = cgroup_file_poll, .seq_show = cgroup_seqfile_show, }; @@ -3575,6 +3586,7 @@ static struct kernfs_ops cgroup_kf_ops = { .open = cgroup_file_open, .release = cgroup_file_release, .write = cgroup_file_write, + .poll = cgroup_file_poll, .seq_start = cgroup_seqfile_start, .seq_next = cgroup_seqfile_next, .seq_stop = cgroup_seqfile_stop, |