From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [Xen-devel] [PATCH] xen: release lock occasionally during ballooning Date: Mon, 20 Jul 2015 11:15:58 +0100 Message-ID: <55ACCA5E.9070100@citrix.com> References: <1436539354-27850-1-git-send-email-jgross@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1436539354-27850-1-git-send-email-jgross@suse.com> Sender: linux-kernel-owner@vger.kernel.org To: Juergen Gross , linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, konrad.wilk@oracle.com, david.vrabel@citrix.com, boris.ostrovsky@oracle.com List-Id: xen-devel@lists.xenproject.org On 10/07/15 15:42, Juergen Gross wrote: > When dom0 is being ballooned balloon_process() will hold the balloon > mutex until it is finished. This will block e.g. creation of new > domains as the device backends for the new domain need some > autoballooned pages for the ring buffers. > > Avoid this by releasing the balloon mutex from time to time during > ballooning. Add a state variable to indicate one balloon_process() > is active to avoid multiple balloon processes fighting for the mutex. Is this state variable necessary? balloon_process() is a work item so there should only be one instance of it running anyway, yes? David