From: "H. Peter Anvin" <hpa@zytor.com>
To: Sarah Newman <srn@prgmr.com>, David Vrabel <david.vrabel@citrix.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, xen-devel@lists.xen.org,
Suresh Siddha <sbsiddha@gmail.com>
Subject: Re: [Xen-devel] [PATCHv1] x86: don't schedule when handling #NM exception
Date: Sun, 16 Mar 2014 20:43:18 -0700 [thread overview]
Message-ID: <53266F56.9030909@zytor.com> (raw)
In-Reply-To: <53266D94.70902@prgmr.com>
On 03/16/2014 08:35 PM, Sarah Newman wrote:
> Can you please review my patch first? It's only enabled when absolutely required.
It doesn't help. It means you're running on Xen, and you will have
processes subjected to random SIGKILL because they happen to touch the
FPU when the atomic pool is low.
However, there is probably a happy medium: you don't actually need eager
FPU restore, you just need eager FPU *allocation*. We have been
intending to allocate the FPU state at task creation time for eagerfpu,
and Suresh Siddha has already produced such a patch; it just needs some
minor fixups due to an __init failure.
http://lkml.kernel.org/r/1391325599.6481.5.camel@europa
In the Xen case we could turn on eager allocation but not eager fpu. In
fact, it might be justified to *always* do eager allocation...
-hpa
next prev parent reply other threads:[~2014-03-17 3:43 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-10 16:17 [PATCHv1] x86: don't schedule when handling #NM exception David Vrabel
2014-03-10 16:40 ` H. Peter Anvin
2014-03-10 17:15 ` David Vrabel
2014-03-10 17:25 ` H. Peter Anvin
2014-03-10 17:25 ` H. Peter Anvin
2014-03-17 3:13 ` Sarah Newman
2014-03-17 3:13 ` Sarah Newman
2014-03-17 3:30 ` [PATCH] x86: Control CR0 TS behavior using dev_na_ts_allowed Sarah Newman
2014-03-17 8:38 ` Jan Beulich
2014-03-17 12:42 ` George Dunlap
2014-03-17 13:35 ` Jan Beulich
2014-03-17 14:05 ` George Dunlap
2014-03-17 14:18 ` George Dunlap
2014-03-17 15:28 ` Jan Beulich
2014-03-18 18:07 ` Sarah Newman
2014-03-18 19:14 ` David Vrabel
2014-03-17 12:44 ` George Dunlap
2014-03-17 13:35 ` Jan Beulich
2014-03-18 17:48 ` 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 3:32 ` Sarah Newman
2014-03-17 3:33 ` [PATCHv1] x86: don't schedule when handling #NM exception H. Peter Anvin
2014-03-17 3:35 ` Sarah Newman
2014-03-17 3:35 ` [Xen-devel] " Sarah Newman
2014-03-17 3:43 ` H. Peter Anvin [this message]
2014-03-17 4:12 ` Sarah Newman
2014-03-17 4:12 ` [Xen-devel] " Sarah Newman
2014-03-17 4:23 ` H. Peter Anvin
2014-03-17 4:23 ` [Xen-devel] " H. Peter Anvin
2014-03-20 0:00 ` Greg Kroah-Hartman
2014-03-20 0:00 ` [Xen-devel] " Greg Kroah-Hartman
2014-03-20 2:29 ` H. Peter Anvin
2014-03-20 2:29 ` H. Peter Anvin
2014-03-17 13:29 ` David Vrabel
2014-03-17 13:29 ` [Xen-devel] " 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
2014-06-23 13:08 ` [Xen-devel] " Konrad Rzeszutek Wilk
2015-03-05 22:08 ` H. Peter Anvin
2015-03-05 22:08 ` [Xen-devel] " 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
2015-03-06 11:46 ` David Vrabel
2014-03-19 15:02 ` [PATCHv1] x86: don't schedule when handling #NM exception H. Peter Anvin
2014-03-19 13:21 ` Konrad Rzeszutek Wilk
2014-03-17 3:43 ` H. Peter Anvin
2014-03-17 12:19 ` George Dunlap
2014-03-17 12:19 ` [Xen-devel] " George Dunlap
2014-03-17 16:55 ` H. Peter Anvin
2014-03-17 16:55 ` [Xen-devel] " H. Peter Anvin
2014-03-17 17:05 ` Jan Beulich
2014-03-17 17:05 ` [Xen-devel] " Jan Beulich
2014-03-17 17:12 ` H. Peter Anvin
2014-03-17 17:12 ` [Xen-devel] " H. Peter Anvin
2014-03-18 8:14 ` Ingo Molnar
2014-03-18 8:14 ` [Xen-devel] " Ingo Molnar
2014-03-17 17:14 ` George Dunlap
2014-03-17 17:14 ` [Xen-devel] " George Dunlap
2014-03-18 18:17 ` Sarah Newman
2014-03-18 18:27 ` H. Peter Anvin
2014-03-18 18:27 ` H. Peter Anvin
2014-03-18 18:17 ` Sarah Newman
2014-03-17 3:33 ` H. Peter Anvin
2014-03-10 17:15 ` David Vrabel
2014-03-10 16:40 ` H. Peter Anvin
2014-03-10 16:45 ` H. Peter Anvin
2014-03-10 16:45 ` H. Peter Anvin
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