Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756013Ab3IYOxZ (ORCPT ); Wed, 25 Sep 2013 10:53:25 -0400 Received: from mail-la0-f53.google.com ([209.85.215.53]:52159 "EHLO mail-la0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755464Ab3IYOxY (ORCPT ); Wed, 25 Sep 2013 10:53:24 -0400 MIME-Version: 1.0 In-Reply-To: <5242C960.7050506@hurleysoftware.com> References: <20130913005133.GA32479@localhost> <20130913010936.GA1291@localhost> <5238767D.1080606@hurleysoftware.com> <20130917232214.GA11390@localhost> <5238F252.5070905@hurleysoftware.com> <5242C960.7050506@hurleysoftware.com> Date: Wed, 25 Sep 2013 22:53:22 +0800 Message-ID: Subject: Re: increased vmap_area_lock contentions on "n_tty: Move buffers into n_tty_data" From: Lin Ming To: Peter Hurley Cc: Fengguang Wu , Greg KH , LKML , lkp@01.org, Tejun Heo Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1068 Lines: 41 On Wed, Sep 25, 2013 at 7:30 PM, Peter Hurley wrote: > On 09/25/2013 05:04 AM, Lin Ming wrote: >> >> On Wed, Sep 18, 2013 at 8:22 AM, Peter Hurley >> wrote: >> [snip] >>> >>> >>> Looking over vmalloc.c, the critical section footprint of the >>> vmap_area_lock >>> could definitely be reduced (even nearly eliminated), but that's a >>> project >>> for >>> another day :) >> >> >> Hi Peter, >> >> I also looked over vmallo.c, but didn't find obvious way to reduce the >> critical section footprint. >> Could you share some hints how to do this? > > > vmap_area_list is an RCU list. > get_vmalloc_info() doesn't need to take the vmap_area_lock at all. > Look at __purge_vmap_area_lazy() for a howto. Looking at it now ... Thanks, Lin Ming > > Regards, > Peter Hurley > -- 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/