From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Sender: Tejun Heo Date: Tue, 11 Sep 2018 16:50:09 -0700 From: Tejun Heo To: Dennis Zhou Cc: Jens Axboe , Johannes Weiner , Josef Bacik , kernel-team@fb.com, linux-block@vger.kernel.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 03/12] blkcg: convert blkg_lookup_create to find closest blkg Message-ID: <20180911235009.GC2966370@devbig004.ftw2.facebook.com> References: <20180911184137.35897-1-dennisszhou@gmail.com> <20180911184137.35897-4-dennisszhou@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20180911184137.35897-4-dennisszhou@gmail.com> List-ID: On Tue, Sep 11, 2018 at 02:41:28PM -0400, Dennis Zhou wrote: > From: "Dennis Zhou (Facebook)" > > There are several scenarios where blkg_lookup_create can fail. Examples > include the blkcg dying, request_queue is dying, or simply being OOM. At > the end of the day, most handle this by simply falling back to the > q->root_blkg and calling it a day. > > This patch implements the notion of closest blkg. During > blkg_lookup_create, if it fails to create, return the closest blkg > found or the q->root_blkg. blkg_try_get_closest is introduced and used > during association so a bio is always attached to a blkg. > > Signed-off-by: Dennis Zhou Acked-by: Tejun Heo Thanks. -- tejun