Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936206Ab3DIUcv (ORCPT ); Tue, 9 Apr 2013 16:32:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56956 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933489Ab3DIUcu (ORCPT ); Tue, 9 Apr 2013 16:32:50 -0400 Date: Tue, 9 Apr 2013 16:32:28 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@file.rdu.redhat.com To: Tejun Heo cc: Jens Axboe , Vivek Goyal , Mike Snitzer , Milan Broz , dm-devel@redhat.com, Andi Kleen , dm-crypt@saout.de, linux-kernel@vger.kernel.org, Christoph Hellwig , Christian Schmidt Subject: Re: dm-crypt parallelization patches In-Reply-To: <20130409195259.GL6186@mtj.dyndns.org> Message-ID: References: <20130328185327.GF14088@htj.dyndns.org> <20130328193343.GA15969@redhat.com> <20130328194443.GG14088@htj.dyndns.org> <20130328203808.GC15969@redhat.com> <20130328204522.GA25501@mtj.dyndns.org> <20130409175753.GA6186@mtj.dyndns.org> <20130409181031.GC6186@mtj.dyndns.org> <20130409195259.GL6186@mtj.dyndns.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3479 Lines: 101 On Tue, 9 Apr 2013, Tejun Heo wrote: > On Tue, Apr 09, 2013 at 03:42:16PM -0400, Mikulas Patocka wrote: > > If I drop ifdefs, it doesn't compile (because other cgroup stuff it > > missing). > > > > So I enabled bio cgroups. > > > > bio_associate_current can't be used, because by the time we allocate the > > outgoing write bio, we are no longer in the process that submitted the > > original bio. > > Oh, I suppose it'd need some massaging to selectively turn off the > cgroup part. > > > Anyway, I tried to reproduce in dm-crypt what bio_associate_current does - > > and we probably need to change that to bio_associate_task(). Generally, we shouldn't associate bios with "current" task in device mapper targets. For example suppose that we have two stacked dm-crypt targets: In the "current" process pointer in lower dm-crypt target's request function always points to the workqueue of the upper dm-crypt target that submits the bios. So if we associate the bio with "current" in the lower target, we are associating it with a preallocated workqueue and we already lost the information who submitted it. You should associate a bio with a task when you create the bio and "md" and "dm" midlayers should just forward this association to lower layer bios. > > in the submitting process I record "ioc" and "css" fields in "dm_crypt_io" > > structure and set these fields on all outgoing bios. It has no effect on > > performance, it is as bad as if I hadn't done it. > > A good way to verify that the tagging is correct would be configuring > io limits in block cgroup and see whether the limits are correctly > applied when going through dm-crypt (please test with direct-io or > reads, writeback is horribly broken, sorry).working correctly, maybe > plugging is the overriding factor? > > Thanks. It doesn't work because device mapper on the underlying layers ignores bi_ioc and bi_css. If I make device mapper forward bi_ioc and bi_css to outgoing bios, it improves performance (from 2:30 to 1:30), but it is still far from perfect. Mikulas --- dm: forward cgroup context This patch makes dm forward associated cgroup context to cloned bios. Signed-off-by: Mikulas Patocka --- drivers/md/dm.c | 9 +++++++++ fs/bio.c | 2 ++ 2 files changed, 11 insertions(+) Index: linux-3.8.6-fast/drivers/md/dm.c =================================================================== --- linux-3.8.6-fast.orig/drivers/md/dm.c 2013-04-09 22:00:36.000000000 +0200 +++ linux-3.8.6-fast/drivers/md/dm.c 2013-04-09 22:19:40.000000000 +0200 @@ -453,6 +453,10 @@ static void free_io(struct mapped_device static void free_tio(struct mapped_device *md, struct dm_target_io *tio) { +#ifdef CONFIG_BLK_CGROUP + tio->clone.bi_ioc = NULL; + tio->clone.bi_css = NULL; +#endif bio_put(&tio->clone); } @@ -1124,6 +1128,11 @@ static struct dm_target_io *alloc_tio(st clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, ci->md->bs); tio = container_of(clone, struct dm_target_io, clone); +#ifdef CONFIG_BLK_CGROUP + tio->clone.bi_ioc = ci->bio->bi_ioc; + tio->clone.bi_css = ci->bio->bi_css; +#endif + tio->io = ci->io; tio->ti = ti; memset(&tio->info, 0, sizeof(tio->info)); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/