Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753813Ab0AHPwa (ORCPT ); Fri, 8 Jan 2010 10:52:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753633Ab0AHPw3 (ORCPT ); Fri, 8 Jan 2010 10:52:29 -0500 Received: from nlpi157.sbcis.sbc.com ([207.115.36.171]:45892 "EHLO nlpi157.prodigy.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753437Ab0AHPw2 (ORCPT ); Fri, 8 Jan 2010 10:52:28 -0500 Date: Fri, 8 Jan 2010 09:51:49 -0600 (CST) From: Christoph Lameter X-X-Sender: cl@router.home To: Arjan van de Ven cc: Linus Torvalds , Peter Zijlstra , "Paul E. McKenney" , Peter Zijlstra , KAMEZAWA Hiroyuki , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "minchan.kim@gmail.com" , "hugh.dickins" , Nick Piggin , Ingo Molnar Subject: Re: [RFC][PATCH 6/8] mm: handle_speculative_fault() In-Reply-To: <20100107204940.253ed753@infradead.org> Message-ID: References: <20100104182429.833180340@chello.nl> <20100104182813.753545361@chello.nl> <20100105054536.44bf8002@infradead.org> <20100105192243.1d6b2213@infradead.org> <20100107204940.253ed753@infradead.org> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 859 Lines: 19 On Thu, 7 Jan 2010, Arjan van de Ven wrote: > if an app has to change because our kernel sucks (for no good reason), > "change the app" really is the lame type of answer. We are changing apps all of the time here to reduce the number of system calls. Any system call usually requires context switching, scheduling activities etc. Evil effects if you want the processor for computation and are sensitive to cpu caching effects. It is good to reduce the number of system calls as much as possible. System calls are at best placed to affect the largest memory possible in a given context and be avoided in loops. -- 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/