From e236a166b2bc437769a9b8b5d19186a3761bde48 Mon Sep 17 00:00:00 2001 From: Andrew Morton <akpm@osdl.org> Date: Wed, 18 Jan 2006 17:42:26 -0800 Subject: [PATCH] mm: dirty_exceeded speedup Ravikiran reports that this variable is bouncing all around nodes on NUMA machines, causing measurable performance problems. Fix that up by only writing to it when it actually changed. And put it in a new cacheline to prevent it sharing with other things (this happened). Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> --- mm/page-writeback.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'mm') diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 5240e426c1f7..945559fb63d2 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -46,7 +46,7 @@ static long ratelimit_pages = 32; static long total_pages; /* The total number of pages in the machine. */ -static int dirty_exceeded; /* Dirty mem may be over limit */ +static int dirty_exceeded __cacheline_aligned_in_smp; /* Dirty mem may be over limit */ /* * When balance_dirty_pages decides that the caller needs to perform some @@ -212,7 +212,8 @@ static void balance_dirty_pages(struct address_space *mapping) if (nr_reclaimable + wbs.nr_writeback <= dirty_thresh) break; - dirty_exceeded = 1; + if (!dirty_exceeded) + dirty_exceeded = 1; /* Note: nr_reclaimable denotes nr_dirty + nr_unstable. * Unstable writes are a feature of certain networked @@ -234,7 +235,7 @@ static void balance_dirty_pages(struct address_space *mapping) blk_congestion_wait(WRITE, HZ/10); } - if (nr_reclaimable + wbs.nr_writeback <= dirty_thresh) + if (nr_reclaimable + wbs.nr_writeback <= dirty_thresh && dirty_exceeded) dirty_exceeded = 0; if (writeback_in_progress(bdi)) -- cgit v1.2.2