From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx137.postini.com [74.125.245.137]) by kanga.kvack.org (Postfix) with SMTP id 4FA726B0044 for ; Mon, 5 Nov 2012 20:49:43 -0500 (EST) Received: by mail-pb0-f41.google.com with SMTP id rq2so7741pbb.14 for ; Mon, 05 Nov 2012 17:49:42 -0800 (PST) Date: Tue, 6 Nov 2012 10:49:32 +0900 From: Minchan Kim Subject: Re: [RFC v2] Support volatile range for anon vma Message-ID: <20121106014932.GA4623@barrios> References: <1351560594-18366-1-git-send-email-minchan@kernel.org> <20121031143524.0509665d.akpm@linux-foundation.org> <20121105235443.GA27718@dev3310.snc6.facebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121105235443.GA27718@dev3310.snc6.facebook.com> Sender: owner-linux-mm@kvack.org List-ID: To: Arun Sharma Cc: KOSAKI Motohiro , Paul Turner , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, John Stultz , Christoph Lameter , Android Kernel Team , Robert Love , Mel Gorman , Hugh Dickins , Dave Hansen , Rik van Riel , Dave Chinner , Neil Brown , Mike Hommey , Taras Glek , KAMEZAWA Hiroyuki , sanjay@google.com, David Rientjes Hello, On Mon, Nov 05, 2012 at 03:54:43PM -0800, Arun Sharma wrote: > On Wed, Oct 31, 2012 at 06:56:05PM -0400, KOSAKI Motohiro wrote: > > glibc malloc discard freed memory by using MADV_DONTNEED > > as tcmalloc. and it is often a source of large performance decrease. > > because of MADV_DONTNEED discard memory immediately and > > right after malloc() call fall into page fault and pagesize memset() path. > > then, using DONTNEED increased zero fill and cache miss rate. > > The memcg based solution that I posted a few months ago is working well > for us. We see significantly less cpu in zero'ing pages. > > Not everyone was comfortable with the security implications of recycling > pages between processes in a memcg, although it was disabled by default > and had to be explicitly opted-in. > > Also, memory allocators have a second motivation in using madvise: to > create virtually contiguous regions of memory from a fragmented address > space, without increasing the RSS. I don't get it. How do we create contiguos region by madvise? Just out of curiosity. Could you elaborate that use case? :) > > -Arun > > -- > 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 -- 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