From: Nick Piggin Date: Tue, 15 Sep 2009 19:34:12 +0000 (+0200) Subject: writeback: improve scalability of bdi writeback work queues X-Git-Tag: v2.6.32-rc1~672^2~2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=77fad5e625e56eb31a343ae1d489979fdc61a2aa;p=platform%2Fkernel%2Flinux-3.10.git 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 Signed-off-by: Jens Axboe --- diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 59c99e7..6bca6f8 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -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;