Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932109Ab1DZHXT (ORCPT ); Tue, 26 Apr 2011 03:23:19 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:45769 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757755Ab1DZHXS convert rfc822-to-8bit (ORCPT ); Tue, 26 Apr 2011 03:23:18 -0400 Subject: Re: [PATCH 0/4] munmap: Flexible mem unmap operation interface for scheduling latency From: Peter Zijlstra To: Geunsik Lim Cc: Ingo Molnar , Andrew Morton , Thomas Gleixner , "H. Peter Anvin" , Hugh Dickins , Steven Rostedt , Darren Hart , linux-kernel , linux-rt-users In-Reply-To: References: <1303728272-11408-1-git-send-email-leemgs1@gmail.com> <1303760837.4865.22.camel@laptop> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Tue, 26 Apr 2011 09:22:52 +0200 Message-ID: <1303802572.20212.4.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1464 Lines: 35 On Tue, 2011-04-26 at 10:20 +0900, Geunsik Lim wrote: > Yes. I also checked the patch that you stated at LKML mailing list previously. > In my thinking. I want to keep ZAP_BLOCK_SIZE related contents > that adjusted by Ingo, Robert, Andrew, and so on a long time ago > because I believe that we can overcome below problems sufficiently > in real world. > . LKML archive - http://lkml.org/lkml/2002/7/24/273 > . LKML archive - http://lkml.org/lkml/2004/9/14/101 Real ancient world, that was 2004, well before we grew preemptible mmu_gather. > In my experience, I did overcome below problems with this patch > based on ZAP_BLOCK_SIZE. > > 1) To solve temporal CPU contention > (e.g: case that cpu contention is 93% ~ 96% according to mmap/munmap > to access mass files ) > 2) To get real-time or real-fast selectively on specified linux system I still don't get it, what kernel are you targeting here and why? -RT doesn't care, and clearly PREEMPT=n doesn't care because its not about latency at all, the only half-way point is PREEMPT=y and for that you could simply reduce ZAP_BLOCK_SIZE. Then again, what's the point, simply remove the whole thing (like I did) and your problem is solved too. -- 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/