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writeback, blkcg: propagate non-root blkcg congestion state 

Now that bdi layer can handle per-blkcg bdi_writeback_congested state,
blk_{set|clear}_congested() can propagate non-root blkcg congestion
state to them.

This can be easily achieved by disabling the root_rl tests in
blk_{set|clear}_congested().  Note that we still need those tests when
!CONFIG_CGROUP_WRITEBACK as otherwise we'll end up flipping root blkcg
wb's congestion state for events happening on other blkcgs.

v2: Updated for bdi_writeback_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>
This commit is contained in:
Tejun Heo 2015-05-22 17:13:43 -04:00 committed by Jens Axboe
parent d40f75a06d
commit 482cf79cdf
1 changed files with 9 additions and 6 deletions
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15
block/blk-core.c
View File

@ -65,23 +65,26 @@ static struct workqueue_struct *kblockd_workqueue;
static void blk_clear_congested(struct request_list *rl, int sync)
{
if (rl != &rl->q->root_rl)
return;
#ifdef CONFIG_CGROUP_WRITEBACK
clear_wb_congested(rl->blkg->wb_congested, sync);
#else
clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
/*
* If !CGROUP_WRITEBACK, all blkg's map to bdi->wb and we shouldn't
* flip its congestion state for events on other blkcgs.
*/
if (rl == &rl->q->root_rl)
clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
#endif
}
static void blk_set_congested(struct request_list *rl, int sync)
{
if (rl != &rl->q->root_rl)
return;
#ifdef CONFIG_CGROUP_WRITEBACK
set_wb_congested(rl->blkg->wb_congested, sync);
#else
set_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
/* see blk_clear_congested() */
if (rl == &rl->q->root_rl)
set_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
#endif
}