From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423828AbcFMVd7 (ORCPT ); Mon, 13 Jun 2016 17:33:59 -0400 Received: from mail-yw0-f178.google.com ([209.85.161.178]:32943 "EHLO mail-yw0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422758AbcFMVd5 (ORCPT ); Mon, 13 Jun 2016 17:33:57 -0400 Date: Mon, 13 Jun 2016 17:33:54 -0400 From: Tejun Heo To: Topi Miettinen Cc: linux-kernel@vger.kernel.org, Li Zefan , Johannes Weiner , "open list:CONTROL GROUP (CGROUP)" Subject: Re: [RFC 02/18] cgroup_pids: track maximum pids Message-ID: <20160613213354.GH31708@htj.duckdns.org> References: <1465847065-3577-1-git-send-email-toiwoton@gmail.com> <1465847065-3577-3-git-send-email-toiwoton@gmail.com> <20160613211227.GG31708@htj.duckdns.org> <17cb1a37-47b1-dbd4-6835-efad3cf6c12f@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <17cb1a37-47b1-dbd4-6835-efad3cf6c12f@gmail.com> User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Mon, Jun 13, 2016 at 09:29:32PM +0000, Topi Miettinen wrote: > I used fork callback as I don't want to lower the watermark in all cases > where the charge can be lowered, so I'd update the watermark only when > the fork really happens. I don't think that would make a noticeable difference. That's where we decide whether to grant fork or not after all and thus where the actual usage is. > Is there a better way to compare and set? I don't think atomic_cmpxchg() > does what's needed, cmpxchg loop should do what's necessary although I'm not sure how much being strictly correct matters here. Thanks. -- tejun