From: Chris Snook <csnook@redhat.com>
To: LAPLACE Cyprien <cyprien.laplace@trango-systems.com>
Cc: virtualization@lists.linux-foundation.org,
Linux Kernel <linux-kernel@vger.kernel.org>,
Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: SMP lockup in virtualized environment
Date: Tue, 24 Apr 2007 18:37:51 -0400 [thread overview]
Message-ID: <462E86BF.7010402@redhat.com> (raw)
In-Reply-To: <462E4223.1050109@trango-systems.com>
LAPLACE Cyprien wrote:
> An example: in kernel/pid.c:alloc_pid(), if one of the guest CPUs is
> descheduled when holding the pidmap_lock, what happens to the other
> guest CPUs who want to alloc/free pids ? Are they blocked too ?
Yup. This is where it's really nice to have directed yields, where you tell the
hypervisor to give your physical CPU time to the vcpu that's holding the lock
you're blocking on. I know s390 can do this. Perhaps it's something worth
generalizing in paravirt_ops?
-- Chris
prev parent reply other threads:[~2007-04-24 22:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-24 17:45 SMP lockup in virtualized environment LAPLACE Cyprien
2007-04-24 18:04 ` Jeremy Fitzhardinge
2007-04-24 22:37 ` Chris Snook [this message]
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