From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH v2 01/14] block: Generalized bio pool freeing Date: Thu, 24 May 2012 09:19:14 -0700 Message-ID: <20120524161914.GD27983@google.com> References: <1337817771-25038-1-git-send-email-koverstreet@google.com> <1337817771-25038-2-git-send-email-koverstreet@google.com> <20120524160944.GB27983@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20120524160944.GB27983-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: drbd-dev-bounces-cunTk1MwBs8qoQakbn7OcQ@public.gmane.org Errors-To: drbd-dev-bounces-cunTk1MwBs8qoQakbn7OcQ@public.gmane.org To: Kent Overstreet Cc: axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org, yehuda-L5o5AL9CYN0tUFlbccrkMA@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, neilb-l3A5Bk7waGM@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, mpatocka-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, bharrosh-C4P08NqkoRlBDgjK7y7TUQ@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, sage-BnTBU8nroG7k1uMJSBkQmQ@public.gmane.org, agk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, drbd-dev-cunTk1MwBs8qoQakbn7OcQ@public.gmane.org List-Id: dm-devel.ids On Thu, May 24, 2012 at 09:09:44AM -0700, Tejun Heo wrote: > On Wed, May 23, 2012 at 05:02:38PM -0700, Kent Overstreet wrote: > > With the old code, when you allocate a bio from a bio pool you have to > > implement your own destructor that knows how to find the bio pool the > > bio was originally allocated from. > > > > This adds a new field to struct bio (bi_pool) and changes > > bio_alloc_bioset() to use it. This makes various bio destructors > > unnecessary, so they're then deleted. > > > > Signed-off-by: Kent Overstreet > > Change-Id: I5eb66c1d6910757f4af8755b8857dcbe4619cf8d > > Please drop Change-ID tag and it would be great how you tested the > changes, other than that, > > Acked-by: Tejun Heo To add a bit here too. Please explain "why" you're making this change. Is it because bi_destructor interface is cumbersome? Adding bi_pool is overhead - why is it justified? Is it because one pointer is fine to add to struct bio (which I kinda agree) or are there future changes which will reverse the overhead (which is the case here). In general, I find the descriptions insufficient. They don't describe the reasons and reasoning behind the patch. Thanks. -- tejun From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f54.google.com (mail-pb0-f54.google.com [209.85.160.54]) (using TLSv1 with cipher RC4-MD5 (128/128 bits)) (No client certificate requested) by mail09.linbit.com (LINBIT Mail Daemon) with ESMTPS id 34D65100008C for ; Thu, 24 May 2012 18:19:20 +0200 (CEST) Received: by mail-pb0-f54.google.com with SMTP id ro2so605089pbb.27 for ; Thu, 24 May 2012 09:19:19 -0700 (PDT) Sender: Tejun Heo Date: Thu, 24 May 2012 09:19:14 -0700 From: Tejun Heo To: Kent Overstreet Message-ID: <20120524161914.GD27983@google.com> References: <1337817771-25038-1-git-send-email-koverstreet@google.com> <1337817771-25038-2-git-send-email-koverstreet@google.com> <20120524160944.GB27983@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120524160944.GB27983@google.com> Cc: axboe@kernel.dk, yehuda@hq.newdream.net, dm-devel@redhat.com, neilb@suse.de, linux-kernel@vger.kernel.org, linux-bcache@vger.kernel.org, mpatocka@redhat.com, vgoyal@redhat.com, bharrosh@panasas.com, linux-fsdevel@vger.kernel.org, sage@newdream.net, agk@redhat.com, drbd-dev@lists.linbit.com Subject: Re: [Drbd-dev] [PATCH v2 01/14] block: Generalized bio pool freeing List-Id: Coordination of development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, May 24, 2012 at 09:09:44AM -0700, Tejun Heo wrote: > On Wed, May 23, 2012 at 05:02:38PM -0700, Kent Overstreet wrote: > > With the old code, when you allocate a bio from a bio pool you have to > > implement your own destructor that knows how to find the bio pool the > > bio was originally allocated from. > > > > This adds a new field to struct bio (bi_pool) and changes > > bio_alloc_bioset() to use it. This makes various bio destructors > > unnecessary, so they're then deleted. > > > > Signed-off-by: Kent Overstreet > > Change-Id: I5eb66c1d6910757f4af8755b8857dcbe4619cf8d > > Please drop Change-ID tag and it would be great how you tested the > changes, other than that, > > Acked-by: Tejun Heo To add a bit here too. Please explain "why" you're making this change. Is it because bi_destructor interface is cumbersome? Adding bi_pool is overhead - why is it justified? Is it because one pointer is fine to add to struct bio (which I kinda agree) or are there future changes which will reverse the overhead (which is the case here). In general, I find the descriptions insufficient. They don't describe the reasons and reasoning behind the patch. Thanks. -- tejun From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757820Ab2EXQTW (ORCPT ); Thu, 24 May 2012 12:19:22 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:58694 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757651Ab2EXQTU (ORCPT ); Thu, 24 May 2012 12:19:20 -0400 Date: Thu, 24 May 2012 09:19:14 -0700 From: Tejun Heo To: Kent Overstreet Cc: linux-kernel@vger.kernel.org, linux-bcache@vger.kernel.org, dm-devel@redhat.com, linux-fsdevel@vger.kernel.org, axboe@kernel.dk, agk@redhat.com, neilb@suse.de, drbd-dev@lists.linbit.com, bharrosh@panasas.com, vgoyal@redhat.com, mpatocka@redhat.com, sage@newdream.net, yehuda@hq.newdream.net Subject: Re: [PATCH v2 01/14] block: Generalized bio pool freeing Message-ID: <20120524161914.GD27983@google.com> References: <1337817771-25038-1-git-send-email-koverstreet@google.com> <1337817771-25038-2-git-send-email-koverstreet@google.com> <20120524160944.GB27983@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120524160944.GB27983@google.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 24, 2012 at 09:09:44AM -0700, Tejun Heo wrote: > On Wed, May 23, 2012 at 05:02:38PM -0700, Kent Overstreet wrote: > > With the old code, when you allocate a bio from a bio pool you have to > > implement your own destructor that knows how to find the bio pool the > > bio was originally allocated from. > > > > This adds a new field to struct bio (bi_pool) and changes > > bio_alloc_bioset() to use it. This makes various bio destructors > > unnecessary, so they're then deleted. > > > > Signed-off-by: Kent Overstreet > > Change-Id: I5eb66c1d6910757f4af8755b8857dcbe4619cf8d > > Please drop Change-ID tag and it would be great how you tested the > changes, other than that, > > Acked-by: Tejun Heo To add a bit here too. Please explain "why" you're making this change. Is it because bi_destructor interface is cumbersome? Adding bi_pool is overhead - why is it justified? Is it because one pointer is fine to add to struct bio (which I kinda agree) or are there future changes which will reverse the overhead (which is the case here). In general, I find the descriptions insufficient. They don't describe the reasons and reasoning behind the patch. Thanks. -- tejun