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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 866DBECDFB8 for ; Mon, 23 Jul 2018 15:13:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3986720881 for ; Mon, 23 Jul 2018 15:13:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3986720881 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388409AbeGWQPU convert rfc822-to-8bit (ORCPT ); Mon, 23 Jul 2018 12:15:20 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:43236 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387968AbeGWQPU (ORCPT ); Mon, 23 Jul 2018 12:15:20 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A955077890; Mon, 23 Jul 2018 15:13:39 +0000 (UTC) Received: from segfault.boston.devel.redhat.com (segfault.boston.devel.redhat.com [10.19.60.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 59D1E7C3E; Mon, 23 Jul 2018 15:13:39 +0000 (UTC) From: Jeff Moyer To: Alex Richman Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: Very slow SYS_io_destroy() References: <27245a6a-a827-2662-215c-05ccdff65768@gblabs.co.uk> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 X-PCLoadLetter: What the f**k does that mean? Date: Mon, 23 Jul 2018 11:13:38 -0400 In-Reply-To: <27245a6a-a827-2662-215c-05ccdff65768@gblabs.co.uk> (Alex Richman's message of "Fri, 20 Jul 2018 20:39:42 +0100") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Mon, 23 Jul 2018 15:13:39 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Mon, 23 Jul 2018 15:13:39 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jmoyer@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alex Richman writes: > Hi, > > I'm seeing some weirdness with AIO, specifically SYS_io_destroy() is > taking upwards of ~100000 microseconds (~100 miliseconds) per call. > How long is that call expected to take?  I can see from the source Well, it waits for an RCU grace period. I would not expect that to take 100ms, though. What kernel version is this? -Jeff