Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751690AbdF1Qx1 (ORCPT ); Wed, 28 Jun 2017 12:53:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:41112 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751533AbdF1QxT (ORCPT ); Wed, 28 Jun 2017 12:53:19 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 542E622BD0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=shli@kernel.org Date: Wed, 28 Jun 2017 09:53:16 -0700 From: Shaohua Li To: Jens Axboe Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, tj@kernel.org, gregkh@linuxfoundation.org, hch@lst.de, rostedt@goodmis.org, lizefan@huawei.com, Kernel-team@fb.com, Shaohua Li Subject: Re: [PATCH V4 00/12] blktrace: output cgroup info Message-ID: <20170628165316.nozfbdvmpflqwt3f@kernel.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1623 Lines: 33 On Wed, Jun 28, 2017 at 10:43:48AM -0600, Jens Axboe wrote: > On 06/28/2017 10:29 AM, Shaohua Li wrote: > > From: Shaohua Li > > > > Hi, > > > > Currently blktrace isn't cgroup aware. blktrace prints out task name of current > > context, but the task of current context isn't always in the cgroup where the > > BIO comes from. We can't use task name to find out IO cgroup. For example, > > Writeback BIOs always comes from flusher thread but the BIOs are for different > > blk cgroups. Request could be requeued and dispatched from completely different > > tasks. MD/DM are another examples. This brings challenges if we want to use > > blktrace for performance tunning with cgroup enabled. > > > > This patchset try to fix the gap. We print out cgroup fhandle info in blktrace. > > Userspace can use open_by_handle_at() syscall to find the cgroup by fhandle. Or > > userspace can use name_to_handle_at() syscall to find fhandle for a cgroup and > > use a BPF program to filter out blktrace for a specific cgroup. > > > > The first 6 patches adds export operation handlers for kernfs, so userspace can > > use open_by_handle_at/name_to_handle_at to a kernfs file. Later patches make > > blktrace output cgroup info. > > Series looks fine to me. I don't know how you want to split or funnel it, > since it touches multiple different parts. Would it make sense to split this > series into two - one for the kernfs changes, and then a subsequent block > series that depend on that? What's the best practice to do this without building errors? Ask Tejun to merge the first 7 patches first? Thanks, Shaohua