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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,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 8E583C433F5 for ; Wed, 5 Sep 2018 12:07:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F0EA20658 for ; Wed, 5 Sep 2018 12:07:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4F0EA20658 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=BitWizard.nl 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 S1727666AbeIEQho (ORCPT ); Wed, 5 Sep 2018 12:37:44 -0400 Received: from cust-95-128-94-82.breedbanddelft.nl ([95.128.94.82]:50784 "EHLO cust-95-128-94-82.breedbanddelft.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727311AbeIEQhn (ORCPT ); Wed, 5 Sep 2018 12:37:43 -0400 Received: by abra2.bitwizard.nl (Postfix, from userid 1000) id 15BF013F6ED; Wed, 5 Sep 2018 14:07:46 +0200 (CEST) Date: Wed, 5 Sep 2018 14:07:46 +0200 From: Rogier Wolff To: Jeff Layton Cc: =?utf-8?B?54Sm5pmT5Yas?= , bfields@fieldses.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: POSIX violation by writeback error Message-ID: <20180905120745.GP17123@BitWizard.nl> References: <82ffc434137c2ca47a8edefbe7007f5cbecd1cca.camel@redhat.com> <20180904161203.GD17478@fieldses.org> <20180904162348.GN17123@BitWizard.nl> <20180904185411.GA22166@fieldses.org> <09ba078797a1327713e5c2d3111641246451c06e.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <09ba078797a1327713e5c2d3111641246451c06e.camel@redhat.com> Organization: BitWizard B.V. User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 05, 2018 at 06:55:15AM -0400, Jeff Layton wrote: > There is no requirement for a filesystem to flush data on close(). And you can't start doing things like that. In some weird cases, you might have an application open-write-close files at a much higher rate than what a harddisk can handle. And this has worked for years because the kernel caches stuff from inodes and data-blocks. If you suddenly write stuff to harddisk at 10ms for each seek between inode area and data-area... You end up limited to about 50 of these open-write-close cycles per second. My home system is now able make/write/close about 100000 files per second. assurancetourix:~/testfiles> time ../a.out 100000 000 0.103u 0.999s 0:01.10 99.0% 0+0k 0+800000io 0pf+0w (The test program was accessing arguments beyond the end-of-arguments, An extra argument for this one time program was easier than open/fix/recompile). Roger. -- ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2600998 ** ** Delftechpark 26 2628 XH Delft, The Netherlands. KVK: 27239233 ** *-- BitWizard writes Linux device drivers for any device you may have! --* The plan was simple, like my brother-in-law Phil. But unlike Phil, this plan just might work.