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From: David Vrabel <david.vrabel@citrix.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>, <xen-devel@lists.xen.org>,
	Sarah Newman <srn@prgmr.com>
Subject: Re: [PATCHv1] x86: don't schedule when handling #NM exception
Date: Mon, 10 Mar 2014 17:15:05 +0000	[thread overview]
Message-ID: <531DF319.6010800@citrix.com> (raw)
In-Reply-To: <531DEB11.2070709@zytor.com>

On 10/03/14 16:40, H. Peter Anvin wrote:
> On 03/10/2014 09:17 AM, David Vrabel wrote:
>> math_state_restore() is called from the #NM exception handler.  It may
>> do a GFP_KERNEL allocation (in init_fpu()) which may schedule.
>>
>> Change this allocation to GFP_ATOMIC, but leave all the other callers
>> of init_fpu() or fpu_alloc() using GFP_KERNEL.
> 
> And what the [Finnish] do you do if GFP_ATOMIC fails?

The same thing it used to do -- kill the task with SIGKILL.  I haven't
changed this behaviour.

> Sarah's patchset switches Xen PV to use eagerfpu unconditionally, which
> removes the dependency on #NM and is the right thing to do.

Ok. I'll wait for this series and not pursue this patch any further.

David

  reply	other threads:[~2014-03-10 17:15 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-10 16:17 David Vrabel
2014-03-10 16:40 ` H. Peter Anvin
2014-03-10 17:15   ` David Vrabel [this message]
2014-03-10 17:25     ` H. Peter Anvin
2014-03-17  3:13     ` Sarah Newman
2014-03-17  3:32       ` [PATCH] x86, fpu, xen: Allocate fpu state for xen pv based on PVABI behavior Sarah Newman
2014-03-17  3:33       ` [PATCHv1] x86: don't schedule when handling #NM exception H. Peter Anvin
2014-03-17  3:35         ` [Xen-devel] " Sarah Newman
2014-03-17  3:43           ` H. Peter Anvin
2014-03-17  4:12             ` Sarah Newman
2014-03-17  4:23               ` H. Peter Anvin
2014-03-20  0:00                 ` Greg Kroah-Hartman
2014-03-20  2:29                   ` H. Peter Anvin
2014-03-17 13:29             ` David Vrabel
2014-03-19 13:21               ` Konrad Rzeszutek Wilk
2014-03-19 15:02                 ` H. Peter Anvin
2014-06-23 13:08                   ` Konrad Rzeszutek Wilk
2015-03-05 22:08                     ` H. Peter Anvin
2015-03-06 11:46                       ` [PATCHv4] x86, fpu: remove the logic of non-eager fpu mem allocation at the first usage David Vrabel
2014-03-17 12:19         ` [Xen-devel] [PATCHv1] x86: don't schedule when handling #NM exception George Dunlap
2014-03-17 16:55           ` H. Peter Anvin
2014-03-17 17:05             ` Jan Beulich
2014-03-17 17:12               ` H. Peter Anvin
2014-03-18  8:14                 ` Ingo Molnar
2014-03-17 17:14               ` George Dunlap
2014-03-18 18:17                 ` Sarah Newman
2014-03-18 18:27                   ` H. Peter Anvin
2014-03-10 16:45 ` H. Peter Anvin

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