From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261793AbVF1Pfu (ORCPT ); Tue, 28 Jun 2005 11:35:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262085AbVF1Pft (ORCPT ); Tue, 28 Jun 2005 11:35:49 -0400 Received: from [212.76.81.187] ([212.76.81.187]:38916 "EHLO raad.intranet") by vger.kernel.org with ESMTP id S261793AbVF1PfW (ORCPT ); Tue, 28 Jun 2005 11:35:22 -0400 Message-Id: <200506281535.SAA30164@raad.intranet> From: "Al Boldi" To: "'Nix'" Cc: "'Marcelo Tosatti'" , Subject: RE: Kswapd flaw Date: Tue, 28 Jun 2005 18:35:00 +0300 MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook, Build 11.0.5510 In-Reply-To: <871x6m5yzd.fsf@amaterasu.srvr.nix> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 Thread-Index: AcV77nSvIFqxlrBMSY+zHp6XBEh9IwABPCGg Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Nix wrote:{ On Tue, 28 Jun 2005, Al Boldi wrote: > Hi Nix, how are you? > You wrote: { > On 28 Jun 2005, Al Boldi yowled: >> Please do flush anytime, and do it in sync during OOMs; but don't >> evict procs especially not RUNNING procs, that is overkill. > > Would you really like a system where once something was faulted in, it > could never leave? You'd run out of memory *awfully* fast. > } > > You should only fault if you have a place to fault to, as into a swap. > Without swap faulting is overkill. > > Is it possible to change kswapd's default behaviour to not fault if > there is no swap? I don't think so, except on a process-by-process basis via mlockall(). (/proc/sys/vm/swappiness lets you say that swapping is more or less desirable, but under enough memory pressure paging *will* happen regardless of the value of that variable.) But I'm mystified as to why you might want to suppress paging. The only effect of suppressing it is to reduce the amount of memory you can allocate before you run completely out and start killing things. } Nix, You start killing things because you overcommitted, when you were not supposed to fault in the first place because you have no swap. ( I couldn't find /proc/sys/vm/swappiness in 2.4, although I heard about it in 2.6.)