writeback, blkcg: propagate non-root blkcg congestion state (482cf79c) · Commits · 戴 / test

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>

block/blk-core.c

+9 −6

Original line number	Diff line number	Diff line
		@@ -65,22 +65,25 @@ 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
		/*
		* 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
		/* see blk_clear_congested() */
		if (rl == &rl->q->root_rl)
		set_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
		#endif
		}

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