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Date: Sun, 16 Mar 2014 20:43:18 -0700 From: "H. Peter Anvin" <hpa@...or.com> To: Sarah Newman <srn@...mr.com>, David Vrabel <david.vrabel@...rix.com> CC: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org, xen-devel@...ts.xen.org, Suresh Siddha <sbsiddha@...il.com> Subject: Re: [Xen-devel] [PATCHv1] x86: don't schedule when handling #NM exception 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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