From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753650AbZIBWUB (ORCPT ); Wed, 2 Sep 2009 18:20:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753597AbZIBWUA (ORCPT ); Wed, 2 Sep 2009 18:20:00 -0400 Received: from mail-vw0-f195.google.com ([209.85.212.195]:43474 "EHLO mail-vw0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753580AbZIBWT7 convert rfc822-to-8bit (ORCPT ); Wed, 2 Sep 2009 18:19:59 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=m3Oi+19XfJqA/VPssvP4QXHEHw3s0vDSnqBINBUvef9ZRmlrAmtVQCiSiSgP0TKT/c 2/PIAIqzRSeqZvO8xKTNDBLMg/itu+N9T7e89tsryk6bntenXqk6Iq3g4uvhGbhygazV fnVitMj8pRxx5oj+Rv2AmhNjXJkLLaiOAGnBo= MIME-Version: 1.0 In-Reply-To: References: Date: Wed, 2 Sep 2009 18:20:00 -0400 Message-ID: Subject: Re: LowFree pattern From: Adayadil Thomas To: Bill Davidsen Cc: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > What problem did you see that you traced to LowFree? I have set this device as a bridge. Higher latency and low throughput seem to be related to LowFree. There are also packet drops at the interface when LowFree is too low. I have another device which has 4G RAM split into 900M LowMem and the rest as HighMem. In that case also, LowMem goes to a low level, say 8M and although HighMem has ~2G free, the system gives OOPS (related to page_alloc failures) when acting as a bridge (passing packets). On Wed, Sep 2, 2009 at 3:22 PM, Bill Davidsen wrote: > Adayadil Thomas wrote: >> >> Greetings. >> >> I am running a centos linux with 2.6.20 version kernel. The system has >> 1G of RAM. >> >> As time goes by the LowFree becomes really low. Right now it shows >> 137M .. but it goes as low as 8M or so >> >> The command - >> echo 3 > /proc/sys/vm/drop_caches >> brings back the LowFree to way up high. >> >> The question I have is whether the system by itself release the cache >> (drop cache) automatically >> to maintain a reasonable LowFree? >> Is this configurable? >> > You can change the parameters in /rpoc/sys/vm if you wish, but what makes > you think this is needed? Cache is dropped as memory is needed, and > drop_cache in general is a good way to slow the system. > >> Any information or help is much appreciated. >> > What problem did you see that you traced to LowFree? > >> >> cat /proc/meminfo >> MemTotal:      1034788 kB >> MemFree:        138240 kB >> Buffers:         99260 kB >> Cached:         177776 kB >> SwapCached:      51740 kB >> Active:         605172 kB >> Inactive:       113572 kB >> HighTotal:      130720 kB >> HighFree:          252 kB >> LowTotal:       904068 kB >> LowFree:        137988 kB >> SwapTotal:     1048568 kB >> SwapFree:       976332 kB >> Dirty:             380 kB >> Writeback:           0 kB >> AnonPages:      441348 kB >> Mapped:          15540 kB >> Slab:           146088 kB >> SReclaimable:   104288 kB >> SUnreclaim:      41800 kB >> PageTables:       1596 kB >> NFS_Unstable:        0 kB >> Bounce:              0 kB >> CommitLimit:   1565960 kB >> Committed_AS:   590576 kB >> VmallocTotal:   114680 kB >> VmallocUsed:     15052 kB >> VmallocChunk:    99348 kB > > > -- > Bill Davidsen >  "We have more to fear from the bungling of the incompetent than from > the machinations of the wicked."  - from Slashdot > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  http://vger.kernel.org/majordomo-info.html > Please read the FAQ at  http://www.tux.org/lkml/ >