writeback: make laptop_mode_timer_fn() handle multiple bdi_writeback's (a06fd6b1) · Commits · 戴 / test

For cgroup writeback support, all bdi-wide operations should be distributed to all its wb's (bdi_writeback's). This patch updates laptop_mode_timer_fn() so that it invokes wb_start_writeback() on all wb's rather than just the root one. As the intent is writing out all dirty data, there's no reason to split the number of pages to write. Signed-off-by:

Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by:

Jens Axboe <axboe@fb.com>

mm/page-writeback.c

+9 −3

Original line number	Diff line number	Diff line
		@@ -1723,13 +1723,19 @@ void laptop_mode_timer_fn(unsigned long data)
		struct request_queue q = (struct request_queue )data;
		int nr_pages = global_page_state(NR_FILE_DIRTY) +
		global_page_state(NR_UNSTABLE_NFS);
		struct bdi_writeback *wb;
		struct wb_iter iter;

		/*
		* We want to write everything out, not just down to the dirty
		* threshold
		*/
		if (bdi_has_dirty_io(&q->backing_dev_info))
		wb_start_writeback(&q->backing_dev_info.wb, nr_pages, true,
		if (!bdi_has_dirty_io(&q->backing_dev_info))
		return;

		bdi_for_each_wb(wb, &q->backing_dev_info, &iter, 0)
		if (wb_has_dirty_io(wb))
		wb_start_writeback(wb, nr_pages, true,
		WB_REASON_LAPTOP_TIMER);
		}

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