From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754104AbWKGIEK (ORCPT ); Tue, 7 Nov 2006 03:04:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754101AbWKGIEK (ORCPT ); Tue, 7 Nov 2006 03:04:10 -0500 Received: from [213.184.169.47] ([213.184.169.47]:64384 "EHLO raad.intranet") by vger.kernel.org with ESMTP id S1754098AbWKGIEH (ORCPT ); Tue, 7 Nov 2006 03:04:07 -0500 From: Al Boldi To: linux-kernel@vger.kernel.org Subject: Re: ZONE_NORMAL memory exhausted by 4000 TCP sockets Date: Tue, 7 Nov 2006 11:06:53 +0300 User-Agent: KMail/1.5 Cc: netdev@vger.kernel.org, linux-net@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200611071106.53975.a1426z@gawab.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Zhao Xiaoming wrote: > The latest update: > It seems that Linux kernel memory management mechanisms including > buddy and slab algorisms are not very efficient under my test > conditions that tcp stack requires a lot of (hundreds of MB) packet > buffers and release them very frequently. > Here is the proof. After change my kernel configuration to support > 2/2 VM splition, LOMEM consumption reduced to 270M bytes compared with > 640M bytes of the 1/3 kernel. All test conditions are the same and > memory pages allocated by TCP stack are also the same, 34K ~ 38K > pages. In other words, 'lost' memory changed from ~500M to ~130M. > Thus, I have nothing to do but guessing the much more free pages make > the slab/buddy algorisms more efficient and waste less memory. I kind of agree, and always compile for a 2G/2G VM split, as this also seems to affect certain OOM conditions positively. What isn't quite clear though, why is the 2G/2G VM split not the default? Thanks! -- Al