From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Weiner Subject: Re: [PATCH 09/16] mm: page_alloc: Take the ALLOC_NO_WATERMARK check out of the fast path Date: Fri, 18 Apr 2014 14:10:19 -0400 Message-ID: <20140418181019.GF29210@cmpxchg.org> References: <1397832643-14275-1-git-send-email-mgorman@suse.de> <1397832643-14275-10-git-send-email-mgorman@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Linux-MM , Linux-FSDevel To: Mel Gorman Return-path: Content-Disposition: inline In-Reply-To: <1397832643-14275-10-git-send-email-mgorman@suse.de> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Fri, Apr 18, 2014 at 03:50:36PM +0100, Mel Gorman wrote: > ALLOC_NO_WATERMARK is set in a few cases. Always by kswapd, always for > __GFP_MEMALLOC, sometimes for swap-over-nfs, tasks etc. Each of these cases > are relatively rare events but the ALLOC_NO_WATERMARK check is an unlikely > branch in the fast path. This patch moves the check out of the fast path > and after it has been determined that the watermarks have not been met. This > helps the common fast path at the cost of making the slow path slower and > hitting kswapd with a performance cost. It's a reasonable tradeoff. > > Signed-off-by: Mel Gorman Acked-by: Johannes Weiner -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org