Messages in this thread Patch in this message | | | Date | Wed, 16 Sep 2009 05:19:05 +1000 | From | npiggin@suse ... | Subject | [patch 2/5] fs: improve scalability of bdi writeback work queues |
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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> --- fs/fs-writeback.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
Index: linux-2.6/fs/fs-writeback.c =================================================================== --- linux-2.6.orig/fs/fs-writeback.c +++ linux-2.6/fs/fs-writeback.c @@ -736,8 +736,9 @@ static struct bdi_work *get_next_work_it 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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