From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx136.postini.com [74.125.245.136]) by kanga.kvack.org (Postfix) with SMTP id EE6F36B002B for ; Mon, 8 Oct 2012 23:06:12 -0400 (EDT) Date: Tue, 9 Oct 2012 12:10:23 +0900 From: Minchan Kim Subject: Re: CMA and zone watermarks Message-ID: <20121009031023.GF13817@bbox> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Rabin Vincent Cc: Marek Szyprowski , linux-mm@kvack.org, LKML Hello, On Mon, Oct 08, 2012 at 05:41:14PM +0200, Rabin Vincent wrote: > It appears that when CMA is enabled, the zone watermarks are not properly > respected, leading to for example GFP_NOWAIT allocations getting access to the > high pools. > > I ran the following test code which simply allocates pages with GFP_NOWAIT > until it fails, and then tries GFP_ATOMIC. Without CMA, the GFP_ATOMIC > allocation succeeds, with CMA, it fails too. Good spot. By wrong zone_watermark_check, it can consume reserved memory pool. > > Logs attached (includes my patch which prints the migration type in the failure > message http://marc.info/?l=linux-mm&m=134971041701306&w=2), taken on 3.6 > kernel. > Fortunately, recently, Bart sent a patch about that. http://marc.info/?l=linux-mm&m=134763299016693&w=2 Could you test above patches in your kernel? You have to apply [2/4], [3/4], [4/4] and don't need [1/4]. Thanks. -- Kind regards, Minchan Kim -- 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