From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756685AbcEEKIp (ORCPT ); Thu, 5 May 2016 06:08:45 -0400 Received: from mail-wm0-f49.google.com ([74.125.82.49]:37206 "EHLO mail-wm0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756283AbcEEKIm (ORCPT ); Thu, 5 May 2016 06:08:42 -0400 Subject: Re: [PATCH 1/4] lightnvm: add sync and close block I/O types To: =?UTF-8?Q?Javier_Gonz=c3=a1lez?= References: <1462375892-26533-1-git-send-email-javier@cnexlabs.com> <572B1099.6010204@lightnvm.io> Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org From: =?UTF-8?Q?Matias_Bj=c3=b8rling?= Message-ID: <572B1BA8.6070103@lightnvm.io> Date: Thu, 5 May 2016 12:08:40 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/05/2016 11:38 AM, Javier González wrote: > >> On 05 May 2016, at 11:21, Matias Bjørling wrote: >> >> On 05/04/2016 05:31 PM, Javier González wrote: >>> Within a target, I/O requests stem from different paths, which might vary >>> in terms of the data structures being allocated, context, etc. This >>> might impact how the request is treated, or how memory is freed once >>> the bio is completed. >>> >>> Add two different types of I/Os: (i) NVM_IOTYPE_SYNC, which indicates >>> that the I/O is synchronous; and (ii) NVM_IOTYPE_CLOSE_BLK, which >>> indicates that the I/O closes the block to which all the ppas on the >>> request belong to. >>> >>> Signed-off-by: Javier González >>> --- >>> include/linux/lightnvm.h | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h >>> index 29a6890..6c02209 100644 >>> --- a/include/linux/lightnvm.h >>> +++ b/include/linux/lightnvm.h >>> @@ -11,6 +11,8 @@ enum { >>> >>> NVM_IOTYPE_NONE = 0, >>> NVM_IOTYPE_GC = 1, >>> + NVM_IOTYPE_SYNC = 2, >>> + NVM_IOTYPE_CLOSE_BLK = 4, >>> }; >>> >>> #define NVM_BLK_BITS (16) >> >> The sync should not be necessary when the read path is implemented >> using bio_clone. Similarly for NVM_IOTYPE_CLOSE_BLK. The write >> completion can be handled in the bio completion path. > > We need to know where the request comes from; we cannot do it just from > having the bio. This is because we allocate different structures > depending on the type of bio we send. It is not only which bio->end_io > function we have, but which memory needs to be released. Sync is > necessary for the read path when we have a partial bio (data both on > write buffer and disk) that we need to fill up. Also for GC.. In this > case, the bio is to be freed differently. In the case of close the case > is similarly; we do not free memory on the end_io path, but on the caller. > > You can see how these flags are used on pblk. Maybe there is a better > way of doing it that I could not see... > Use the bio completion path for both. For bio completion, free the data that is specific to the pblk flow and let the nvm_rq->end_io() completion path clean up the nvm_rq specific data. That will clean up the completion paths. > Javier >