From owner-freebsd-stable@FreeBSD.ORG Tue Apr 5 17:45:08 2011 Return-Path: Delivered-To: freebsd-stable@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 42A4E1065672 for ; Tue, 5 Apr 2011 17:45:08 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from asmtpout022.mac.com (asmtpout022.mac.com [17.148.16.97]) by mx1.freebsd.org (Postfix) with ESMTP id 23C3C8FC18 for ; Tue, 5 Apr 2011 17:45:07 +0000 (UTC) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; CHARSET=US-ASCII Received: from cswiger1.apple.com ([17.209.4.71]) by asmtp022.mac.com (Oracle Communications Messaging Exchange Server 7u4-20.01 64bit (built Nov 21 2010)) with ESMTPSA id <0LJ6004BCUIAPL90@asmtp022.mac.com> for freebsd-stable@FreeBSD.org; Tue, 05 Apr 2011 09:44:35 -0700 (PDT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.2.15,1.0.148,0.0.0000 definitions=2011-04-05_07:2011-04-05, 2011-04-05, 1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 ipscore=0 suspectscore=0 phishscore=0 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx engine=6.0.2-1012030000 definitions=main-1104050108 From: Chuck Swiger In-reply-to: Date: Tue, 05 Apr 2011 09:44:34 -0700 Message-id: <62BEFA1C-9A7D-4981-9F71-6DE15973B7C1@mac.com> References: To: Pete French X-Mailer: Apple Mail (2.1084) Cc: FreeBSD-STABLE Mailing List Subject: Re: Kernel memory leak in 8.2-PRERELEASE? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 05 Apr 2011 17:45:08 -0000 On Apr 5, 2011, at 7:54 AM, Pete French wrote: >> Having swap provides some cushion. Swap kind of smooths any bursts. (And it can >> also slow things down as a side effect) > > This is why I got rid of it - my application is a lot of CGI scripts. The > overload condition is that we run out of memory - and we run *way* out > of memory .... its never just a little overflow, it;s either handleable or > completely crushed. But swap makes that mre llikely to happen, because > as the processes are swapped out they run slower, take longer to > finish and thus use memory for longer. > > What I saw was that as soon as any web server would start tos wap it would > swftly fall down. Without swap they stay up, but reject requests. Its a better > failure mode... You'll be better off providing swap space with every machine, and tuning Apache's MaxClients to a suitable value such that you don't swap excessively under load spikes. Without any swap, the system will be unable to page out unused portions of processes and will handle less load than it would with swap available. Regards, -- -Chuck