From: Mel Gorman <[email protected]> 3.12-stable review patch. If anyone has any objections, please let me know.
=============== commit 65bb371984d6a2c909244eb749e482bb40b72e36 upstream. The zlc is used on NUMA machines to quickly skip over zones that are full. However it is always updated, even for the first zone scanned when the zlc might not even be active. As it's a write to a bitmap that potentially bounces cache line it's deceptively expensive and most machines will not care. Only update the zlc if it was active. Signed-off-by: Mel Gorman <[email protected]> Acked-by: Johannes Weiner <[email protected]> Reviewed-by: Rik van Riel <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Mel Gorman <[email protected]> Signed-off-by: Jiri Slaby <[email protected]> --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7139ed7c9a70..2834c31ad0c1 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2034,7 +2034,7 @@ try_this_zone: if (page) break; this_zone_full: - if (IS_ENABLED(CONFIG_NUMA)) + if (IS_ENABLED(CONFIG_NUMA) && zlc_active) zlc_mark_zone_full(zonelist, z); } -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
