From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41050) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fkV0O-0005s9-6k for qemu-devel@nongnu.org; Tue, 31 Jul 2018 09:48:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fkV0J-0008Ob-F5 for qemu-devel@nongnu.org; Tue, 31 Jul 2018 09:48:04 -0400 From: Alberto Garcia In-Reply-To: <20180704145410.794-1-stefanha@redhat.com> References: <20180704145410.794-1-stefanha@redhat.com> Date: Tue, 31 Jul 2018 15:47:20 +0200 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH] throttle-groups: fix hang when group member leaves List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi , qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, Kevin Wolf , Max Reitz On Wed 04 Jul 2018 04:54:10 PM CEST, Stefan Hajnoczi wrote: > Throttle groups consist of members sharing one throttling state > (including bps/iops limits). Round-robin scheduling is used to ensure > fairness. If a group member already has a timer pending then other > groups members do not schedule their own timers. The next group > member will have its turn when the existing timer expires. > > A hang may occur when a group member leaves while it had a timer > scheduled. I haven't been able to reproduce this. When a member is removed from the group the pending request queue must already be empty, so does this mean that there's still a timer when the queue is already empty? Berto