From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762069AbcALBp1 (ORCPT ); Mon, 11 Jan 2016 20:45:27 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:31143 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760002AbcALBpW (ORCPT ); Mon, 11 Jan 2016 20:45:22 -0500 Date: Mon, 11 Jan 2016 20:45:09 -0500 From: Chris Mason To: Linus Torvalds CC: Benjamin LaHaise , Ingo Molnar , , linux-fsdevel , Linux Kernel Mailing List , Linux API , linux-mm , Alexander Viro , Andrew Morton Subject: Re: [PATCH 09/13] aio: add support for async openat() Message-ID: <20160112014509.z6xefgc2rrkytmvk@ret.masoncoding.com> Mail-Followup-To: Chris Mason , Linus Torvalds , Benjamin LaHaise , Ingo Molnar , linux-aio@kvack.org, linux-fsdevel , Linux Kernel Mailing List , Linux API , linux-mm , Alexander Viro , Andrew Morton References: <150a0b4905f1d7274b4c2c7f5e3f4d8df5dda1d7.1452549431.git.bcrl@kvack.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23.1 (2014-03-12) X-Originating-IP: [192.168.52.123] X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-01-11_13:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 11, 2016 at 04:22:28PM -0800, Linus Torvalds wrote: > On Mon, Jan 11, 2016 at 2:07 PM, Benjamin LaHaise wrote: > > Another blocking operation used by applications that want aio > > functionality is that of opening files that are not resident in memory. > > Using the thread based aio helper, add support for IOCB_CMD_OPENAT. > > So I think this is ridiculously ugly. > > AIO is a horrible ad-hoc design, with the main excuse being "other, > less gifted people, made that design, and we are implementing it for > compatibility because database people - who seldom have any shred of > taste - actually use it". > > But AIO was always really really ugly. > > Now you introduce the notion of doing almost arbitrary system calls > asynchronously in threads, but then you use that ass-backwards nasty > interface to do so. [ ... ] > I'm adding Ingo the to cc, because I think Ingo had a "run this list > of system calls" patch at one point - in order to avoid system call > overhead. I don't think that was very interesting (because system call > overhead is seldom all that noticeable for any interesting system > calls), but with the "let's do the list asynchronously" addition it > might be much more intriguing. Ingo, do I remember correctly that it > was you? I might be confused about who wrote that patch, and I can't > find it now. Zach Brown and Ingo traded a bunch of ideas. There were chicklets and syslets? A little search, it looks like acall was a slightly different iteration, but the patches didn't make it off oss.oracle.com: https://lwn.net/Articles/316806/ -chris