From 77fad5e625e56eb31a343ae1d489979fdc61a2aa Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Tue, 15 Sep 2009 21:34:12 +0200 Subject: [PATCH] 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 --- fs/fs-writeback.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) 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; -- 2.7.4