From: Dave Hansen <dave.hansen@linux.intel.com>
To: Rik van Riel <riel@redhat.com>, linux-kernel@vger.kernel.org
Cc: x86@kernel.org, tglx@linutronix.de, pbonzini@redhat.com,
mingo@redhat.com, luto@kernel.org, hpa@zytor.com, bp@suse.de
Subject: Re: [PATCH RFC 4/5] x86,fpu: lazily skip FPU restore when still loaded
Date: Mon, 3 Oct 2016 13:49:43 -0700 [thread overview]
Message-ID: <57F2C467.5060007@linux.intel.com> (raw)
In-Reply-To: <1475526171.4622.9.camel@redhat.com>
On 10/03/2016 01:22 PM, Rik van Riel wrote:
>> > What are the preempt rules with this thing? This needs to be called
>> > in preempt-disabled contexts, right?
> Indeed, all the FPU context switching code needs
> to be called in preempt-disabled contexts.
>
> You do not want to get preempted halfway through
> saving or restoring floating point registers.
OK, cool, that's what I expected. Could you just add a comment about it
to make it clear that it's also the case for this new
fpu_lazy_skip_restore() helper?
next prev parent reply other threads:[~2016-10-03 20:50 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-01 20:31 [PATCH RFC 0/5] x86,fpu: make FPU context switching much lazier riel
2016-10-01 20:31 ` [PATCH RFC 1/5] x86,fpu: split prev/next task fpu state handling riel
2016-10-01 23:26 ` Andy Lutomirski
2016-10-02 0:02 ` Rik van Riel
2016-10-01 20:31 ` [PATCH RFC 2/5] x86,fpu: delay FPU register loading until switch to userspace riel
2016-10-01 23:44 ` Andy Lutomirski
2016-10-02 0:08 ` Rik van Riel
2016-10-03 20:54 ` Andy Lutomirski
2016-10-03 21:21 ` Rik van Riel
2016-10-03 21:36 ` Andy Lutomirski
2016-10-04 1:29 ` Rik van Riel
2016-10-04 2:09 ` Andy Lutomirski
2016-10-04 2:47 ` Rik van Riel
2016-10-04 3:02 ` Andy Lutomirski
2016-10-04 6:35 ` Ingo Molnar
2016-10-04 12:48 ` Rik van Riel
2016-10-04 2:11 ` Rik van Riel
2016-10-04 3:02 ` Andy Lutomirski
2016-10-02 0:42 ` Rik van Riel
2016-10-03 16:23 ` Dave Hansen
2016-10-01 20:31 ` [PATCH RFC 3/5] x86,fpu: add kernel fpu argument to __kernel_fpu_begin riel
2016-10-01 20:31 ` [PATCH RFC 4/5] x86,fpu: lazily skip FPU restore when still loaded riel
2016-10-03 20:04 ` Dave Hansen
2016-10-03 20:22 ` Rik van Riel
2016-10-03 20:49 ` Dave Hansen [this message]
2016-10-03 21:02 ` Rik van Riel
2016-10-01 20:31 ` [PATCH RFC 5/5] x86,fpu: kinda sorta fix up signal path riel
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