[PATCH 5/5] blkcg: Add cgroup file to configure blkcg::blkg_aio_max_nr
From: Kirill Tkhai <hidden>
Date: 2017-12-04 16:13:58
Also in:
lkml
Subsystem:
block layer, control group - block io controller (blkio), the rest · Maintainers:
Jens Axboe, Tejun Heo, Josef Bacik, Linus Torvalds
Add a file to configure per-cgroup maximum number of available aio requests. Allow write the values, which are less then currently allocated numbers of requests. Show numbers of currently allocated and maximum available requests. Signed-off-by: Kirill Tkhai <redacted> --- block/blk-cgroup.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 9cc6e9574946..dc5600ef4523 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c@@ -981,12 +981,52 @@ static int blkcg_print_stat(struct seq_file *sf, void *v) return 0; } +#ifdef CONFIG_AIO +static int blkcg_write_aio_max_nr(struct cgroup_subsys_state *css, + struct cftype *cftype, u64 val) +{ + struct blkcg *blkg = css_to_blkcg(css); + int ret = 0; + + percpu_down_read(&cgroup_threadgroup_rwsem); + spin_lock(&aio_nr_lock); + if (val >= blkg->blkg_aio_nr) + blkg->blkg_aio_max_nr = val; + else + ret = -EBUSY; + spin_unlock(&aio_nr_lock); + percpu_up_read(&cgroup_threadgroup_rwsem); + return ret; +} + +static int blkcg_show_aio_nrs(struct seq_file *sf, void *v) +{ + struct blkcg *blkg = css_to_blkcg(seq_css(sf)); + unsigned long max_nr, nr; + + spin_lock(&aio_nr_lock); + max_nr = blkg->blkg_aio_max_nr; + nr = blkg->blkg_aio_nr; + spin_unlock(&aio_nr_lock); + + seq_printf(sf, "used=%lu, max=%lu\n", nr, max_nr); + return 0; +} +#endif /* CONFIG_AIO */ + static struct cftype blkcg_files[] = { { .name = "stat", .flags = CFTYPE_NOT_ON_ROOT, .seq_show = blkcg_print_stat, }, +#ifdef CONFIG_AIO + { + .name = "aio_nr", + .write_u64 = blkcg_write_aio_max_nr, + .seq_show = blkcg_show_aio_nrs, + }, +#endif { } /* terminate */ };