diff options
Diffstat (limited to 'block/blk-cgroup.c')
| -rw-r--r-- | block/blk-cgroup.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index c195365c9817..d33dd6be1d9c 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1613,16 +1613,24 @@ static void blkcg_scale_delay(struct blkcg_gq *blkg, u64 now) static void blkcg_maybe_throttle_blkg(struct blkcg_gq *blkg, bool use_memdelay) { unsigned long pflags; + bool clamp; u64 now = ktime_to_ns(ktime_get()); u64 exp; u64 delay_nsec = 0; int tok; while (blkg->parent) { - if (atomic_read(&blkg->use_delay)) { + int use_delay = atomic_read(&blkg->use_delay); + + if (use_delay) { + u64 this_delay; + blkcg_scale_delay(blkg, now); - delay_nsec = max_t(u64, delay_nsec, - atomic64_read(&blkg->delay_nsec)); + this_delay = atomic64_read(&blkg->delay_nsec); + if (this_delay > delay_nsec) { + delay_nsec = this_delay; + clamp = use_delay > 0; + } } blkg = blkg->parent; } @@ -1634,10 +1642,13 @@ static void blkcg_maybe_throttle_blkg(struct blkcg_gq *blkg, bool use_memdelay) * Let's not sleep for all eternity if we've amassed a huge delay. * Swapping or metadata IO can accumulate 10's of seconds worth of * delay, and we want userspace to be able to do _something_ so cap the - * delays at 1 second. If there's 10's of seconds worth of delay then - * the tasks will be delayed for 1 second for every syscall. + * delays at 0.25s. If there's 10's of seconds worth of delay then the + * tasks will be delayed for 0.25 second for every syscall. If + * blkcg_set_delay() was used as indicated by negative use_delay, the + * caller is responsible for regulating the range. */ - delay_nsec = min_t(u64, delay_nsec, 250 * NSEC_PER_MSEC); + if (clamp) + delay_nsec = min_t(u64, delay_nsec, 250 * NSEC_PER_MSEC); if (use_memdelay) psi_memstall_enter(&pflags); |