From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756704AbcGIOxc (ORCPT ); Sat, 9 Jul 2016 10:53:32 -0400 Received: from mail-qk0-f179.google.com ([209.85.220.179]:34884 "EHLO mail-qk0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751579AbcGIOx1 (ORCPT ); Sat, 9 Jul 2016 10:53:27 -0400 Date: Sat, 9 Jul 2016 10:53:21 -0400 From: Tejun Heo To: Ming Lei Cc: aaronlee0817 , Jens Axboe , Ming Lin , Shaohua Li , Linux Kernel Mailing List , cgroup@vger.kernel.org, jiale0817.li@samsung.com, yanzi.zhang@samsung.com, zhen1.zhang@samsung.com, linux-block Subject: Re: Re: cgroup: Fix split bio been throttled more than once Message-ID: <20160709145321.GA3337@htj.duckdns.org> References: <77238e99.142c5.155b660564f.Coremail.aaronlee0817@163.com> <20160706140919.GH3262@mtj.duckdns.org> <27824f6f.127ab.155c59d8a24.Coremail.aaronlee0817@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Ming. On Fri, Jul 08, 2016 at 06:35:06PM +0800, Ming Lei wrote: > I am wondering why REQ_THROTTLED is cleared for the original bio > even it has been charged and will be issued to driver, and is it allowed > to throttle and charge the same bio for many times? So, IIUC, the flag is just to prevent the bio from recursing while being issued from blk-throtl after queued there for throttling. We can probably extend the flag. I'm not sure how it'd interact with stacked drivers tho. It'd definitely need to be cleared before traveling down to a lower level device. Thanks. -- tejun