From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4ADB4C43219 for ; Sat, 4 May 2019 23:33:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1BBA520449 for ; Sat, 4 May 2019 23:33:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557012790; bh=qh4GWyx6IA4ISYVxjw7+RooUmFqfkX0HC1ZqwK7OyAE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=B/LLS5y1VarTLptieHgbjwGrE4498fkzubzVMQU9NBan3bigcC2O4XKgypGAYmx+t kB+JIT+JFcIq/JEqVe+3NcZAH67poMm0pFrIL4pqjz3TbaBuK7H9wtyaNVhpjULCq3 oyVBrYJ63InBdx3LKbOAc1AtTvJttyjoB+nGhUcw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727343AbfEDXdJ (ORCPT ); Sat, 4 May 2019 19:33:09 -0400 Received: from mx2.suse.de ([195.135.220.15]:53068 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726596AbfEDXdI (ORCPT ); Sat, 4 May 2019 19:33:08 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id A0BA5AEE3; Sat, 4 May 2019 23:33:06 +0000 (UTC) Date: Sat, 4 May 2019 19:33:02 -0400 From: Michal Hocko To: Alexey Dobriyan Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, Oleg Nesterov Subject: Re: [PATCH] signal: reorder struct sighand_struct Message-ID: <20190504233302.GT29835@dhcp22.suse.cz> References: <20190503192800.GA18004@avx2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190503192800.GA18004@avx2> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org CCing Oleg. On Fri 03-05-19 22:28:00, Alexey Dobriyan wrote: [...] > add/remove: 0/0 grow/shrink: 8/68 up/down: 49/-1147 (-1098) [...] > --- a/include/linux/sched/signal.h > +++ b/include/linux/sched/signal.h > @@ -15,10 +15,10 @@ > */ > > struct sighand_struct { > - refcount_t count; > - struct k_sigaction action[_NSIG]; > spinlock_t siglock; > + refcount_t count; > wait_queue_head_t signalfd_wqh; > + struct k_sigaction action[_NSIG]; > }; Is it possible that this would cause false sharing of the cache line that would have performance implications now? -- Michal Hocko SUSE Labs