Commit 77fad5e6 authored Sep 15, 2009 by Nick Piggin Committed by Jens Axboe Sep 16, 2009

writeback: improve scalability of bdi writeback work queues

If you're going to do an atomic RMW on each list entry, there's not much
point in all the RCU complexities of the list walking. This is only going
to help the multi-thread case I guess, but it doesn't hurt to do now.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

parent deed62ed

fs/fs-writeback.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -772,8 +772,9 @@ static struct bdi_work get_next_work_item(struct backing_dev_info bdi,
		rcu_read_lock();

		list_for_each_entry_rcu(work, &bdi->work_list, list) {
		if (!test_and_clear_bit(wb->nr, &work->seen))
		if (!test_bit(wb->nr, &work->seen))
		continue;
		clear_bit(wb->nr, &work->seen);

		ret = work;
		break;

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