Return-Path: Received: from mail-pl1-f196.google.com ([209.85.214.196]:40995 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726008AbeLGWGN (ORCPT ); Fri, 7 Dec 2018 17:06:13 -0500 Received: by mail-pl1-f196.google.com with SMTP id u6so2410833plm.8 for ; Fri, 07 Dec 2018 14:06:13 -0800 (PST) Subject: Re: [PATCHSET v5] Support for polled aio From: Jens Axboe To: Jeff Moyer Cc: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, hch@lst.de References: <20181204233729.26776-1-axboe@kernel.dk> <4bf3dfe4-b157-88b6-f9a3-60ad1f76328a@kernel.dk> <9747f14b-8361-08c0-5a1f-d4f26509083e@kernel.dk> <650ef685-0727-aaf4-aff5-adf11c06f3fa@kernel.dk> <65d4cd53-8c13-3741-1994-98b1297dc714@kernel.dk> <796e20df-3f55-af8f-58c3-45e7a6d2009a@kernel.dk> Message-ID: <03b82fbf-e4cb-6a80-503c-bc043bdd9e8a@kernel.dk> Date: Fri, 7 Dec 2018 15:06:10 -0700 MIME-Version: 1.0 In-Reply-To: <796e20df-3f55-af8f-58c3-45e7a6d2009a@kernel.dk> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 12/7/18 3:00 PM, Jens Axboe wrote: > On 12/7/18 2:59 PM, Jens Axboe wrote: >> On 12/7/18 2:58 PM, Jens Axboe wrote: >>> On 12/7/18 12:35 PM, Jens Axboe wrote: >>>> On 12/7/18 12:34 PM, Jeff Moyer wrote: >>>>> Jens Axboe writes: >>>>> >>>>>> BTW, quick guess is that it doesn't work so well with fixed buffers, as that >>>>>> hasn't been tested. You could try and remove IOCTX_FLAG_FIXEDBUFS from the >>>>>> test program and see if that works. >>>>> >>>>> That results in a NULL pointer dereference. I'll stick to block device >>>>> testing for now. :) >>>> >>>> Good plan :-) >>> >>> Took a look and fixed it up, my aio-poll branch has a fixup patch and I >>> also updated an updated aio-ring.c in the same location. >>> >>> Tested XFS with polling on and off, works for me. >>> >>> Will take a look at FIXEDBUFS now. Note that aio-ring has some parameters >>> at the top: >>> >>> static int polled = 1; /* use IO polling */ >>> static int fixedbufs = 0; /* use fixed user buffers */ >>> >>> that you can change to try the various modes. Don't use fixedbufs = 1 >>> with XFS just yet :-) >> >> Actually, with the other fixups, that works now too. At least in a quick >> test... > > And no, it does not ;-). Will take a look, we're dropping page counts where > we should not be. Forgot to add the BIO_HOLD_PAGES check in iomap, it works now. Pushed out that fix, will also need folding. -- Jens Axboe