From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx116.postini.com [74.125.245.116]) by kanga.kvack.org (Postfix) with SMTP id 48F4D6B0068 for ; Tue, 18 Dec 2012 05:04:54 -0500 (EST) Date: Tue, 18 Dec 2012 10:04:50 +0000 From: Mel Gorman Subject: Re: [patch 3/7] mm: vmscan: clarify how swappiness, highest priority, memcg interact Message-ID: <20121218100449.GK9887@suse.de> References: <1355767957-4913-1-git-send-email-hannes@cmpxchg.org> <1355767957-4913-4-git-send-email-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1355767957-4913-4-git-send-email-hannes@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Andrew Morton , Rik van Riel , Michal Hocko , Hugh Dickins , Satoru Moriya , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Mon, Dec 17, 2012 at 01:12:33PM -0500, Johannes Weiner wrote: > A swappiness of 0 has a slightly different meaning for global reclaim > (may swap if file cache really low) and memory cgroup reclaim (never > swap, ever). > > In addition, global reclaim at highest priority will scan all LRU > lists equal to their size and ignore other balancing heuristics. > UNLESS swappiness forbids swapping, then the lists are balanced based > on recent reclaim effectiveness. UNLESS file cache is running low, > then anonymous pages are force-scanned. > > This (total mess of a) behaviour is implicit and not obvious from the > way the code is organized. At least make it apparent in the code flow > and document the conditions. It will be it easier to come up with > sane semantics later. > > Signed-off-by: Johannes Weiner Acked-by: Mel Gorman -- Mel Gorman SUSE Labs -- 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