From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [Qemu-devel] [RFC] create a single workqueue for each vm to update vm irq routing table Date: Thu, 28 Nov 2013 13:16:53 +0200 Message-ID: <52972625.8050006@cloudius-systems.com> References: <5294B634.4050801@cloudius-systems.com> <20131126150357.GA20352@redhat.com> <5294BC3B.6070902@redhat.com> <5297050E.6000700@redhat.com> <20131128091903.GA4609@kernel.org> <5297118C.3050104@cloudius-systems.com> <529712A1.8090207@redhat.com> <5297181B.3090109@cloudius-systems.com> <52971D86.60601@redhat.com> <20131128110915.GD5822@minantech.com> <529724B0.80405@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "Zhanghaoyu (A)" , Gleb Natapov , Avi Kivity , "Huangweidong (C)" , KVM , "Michael S. Tsirkin" , "Jinxin (F)" , Luonengjun , "qemu-devel@nongnu.org" , Zanghongyong To: Paolo Bonzini , Gleb Natapov Return-path: Received: from mail-bk0-f48.google.com ([209.85.214.48]:59298 "EHLO mail-bk0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752267Ab3K1LQ7 (ORCPT ); Thu, 28 Nov 2013 06:16:59 -0500 Received: by mail-bk0-f48.google.com with SMTP id v10so3671164bkz.7 for ; Thu, 28 Nov 2013 03:16:56 -0800 (PST) In-Reply-To: <529724B0.80405@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 11/28/2013 01:10 PM, Paolo Bonzini wrote: > Il 28/11/2013 12:09, Gleb Natapov ha scritto: >>> - if there are no callbacks, but there are readers, synchronize_srcu >>> busy-loops for some time checking if the readers complete. After a >>> while (20 us for synchronize_srcu, 120 us for >>> synchronize_srcu_expedited) it gives up and starts using a workqueue to >>> poll every millisecond. This should never happen unless >> Unless what ? :) Unless reader is scheduled out? > Yes. Or unless my brain is scheduled out in the middle of a sentence. > You need a grace period. Or just sleep().