Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753452Ab0AEGYr (ORCPT ); Tue, 5 Jan 2010 01:24:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751154Ab0AEGYq (ORCPT ); Tue, 5 Jan 2010 01:24:46 -0500 Received: from mail-pw0-f42.google.com ([209.85.160.42]:55768 "EHLO mail-pw0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750716Ab0AEGYp (ORCPT ); Tue, 5 Jan 2010 01:24:45 -0500 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; b=DIAsXKPEAhcKN4Yd4V9z/XAKijAI93vLOzcnUuG8L28/UII/ZVOqfI1QXNxejT2u0B JXIGyNu+2JkvnfS8rnAumbgx5cG6GPThZ1c8Z24U3iYsZcEJ5m80jg3nTU8VOnL0sz7q jCnPJsOq+YVzJgZgIvqM1d3oUwLDBppx8+HDo= MIME-Version: 1.0 In-Reply-To: <20100105150932.ab2e6820.kamezawa.hiroyu@jp.fujitsu.com> References: <20100104182429.833180340@chello.nl> <20100104182813.753545361@chello.nl> <20100105092559.1de8b613.kamezawa.hiroyu@jp.fujitsu.com> <28c262361001042029w4b95f226lf54a3ed6a4291a3b@mail.gmail.com> <28c262361001042209k7241dd38l3d51d230e7b68a5@mail.gmail.com> <20100105150932.ab2e6820.kamezawa.hiroyu@jp.fujitsu.com> Date: Tue, 5 Jan 2010 15:24:45 +0900 Message-ID: <28c262361001042224u44bad2e8r8eafdbdff673076a@mail.gmail.com> Subject: Re: [RFC][PATCH 6/8] mm: handle_speculative_fault() From: Minchan Kim To: KAMEZAWA Hiroyuki Cc: Linus Torvalds , Peter Zijlstra , "Paul E. McKenney" , Peter Zijlstra , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , cl@linux-foundation.org, "hugh.dickins" , Nick Piggin , Ingo Molnar Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1274 Lines: 42 On Tue, Jan 5, 2010 at 3:09 PM, KAMEZAWA Hiroyuki wrote: > On Tue, 5 Jan 2010 15:09:47 +0900 > Minchan Kim wrote: >> My humble opinion is following as. >> >> Couldn't we synchronize rcu in that cases(munmap, exit and so on)? >> It can delay munap and exit but it would be better than handling them by more >> complicated things, I think. And both cases aren't often cases so we >> can achieve advantage than disadvantage? >> > > In most case, a program is single threaded. And sychronize_rcu() in unmap path > just adds very big overhead. Yes. I suggested you that consider single-thread app's regression, please. :) First I come to my head is we can count number of thread. Yes. thread number is a not good choice. As a matter of fact, I want to work it adaptively. If the process start to have many threads, speculative page fault turn on or turn off. I know it's not easy. I hope other guys have good ideas. > > Thanks, > -Kame > > -- Kind regards, Minchan Kim -- 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/