From: Linus Torvalds <torvalds@linux-foundation.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Don Zickus <dzickus@redhat.com>, Andi Kleen <ak@linux.intel.com>,
dave.hansen@linux.intel.com,
Stephane Eranian <eranian@google.com>,
jmario@redhat.com,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH] perf, x86: Optimize intel_pmu_pebs_fixup_ip()
Date: Wed, 23 Oct 2013 08:09:53 +0100 [thread overview]
Message-ID: <CA+55aFwfsyofuZtNyUGKPWdvqc=4gOW=HTFPxsiM-3GS1G8KKQ@mail.gmail.com> (raw)
In-Reply-To: <20131022211237.GH2490@laptop.programming.kicks-ass.net>
On Tue, Oct 22, 2013 at 10:12 PM, Peter Zijlstra <peterz@infradead.org> wrote:
>>
>> Careful! There is one magic piece of state that you need to
>> save-and-restore if you do this, namely %cr2. Taking a page fault
>> always writes to %cr2, and we must *not* corrupt it in the NMI
>> handler.
>
> It looks like this is already dealt with (a similar thing is done for
> i386).
Oh, ok then, we should be good to go. I wonder why we needed that
special "_nmi()" version, then..
Please do check that NMI increment the irq-counts etc.. Otherwise
you'll need to add the explicit "pagefault_disable/enable()" pair
around the __copy_from_user_inatomic()..
Linus
next prev parent reply other threads:[~2013-10-23 7:09 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-14 20:35 x86, perf: throttling issues with long nmi latencies Don Zickus
2013-10-14 21:28 ` Andi Kleen
2013-10-15 10:14 ` Peter Zijlstra
2013-10-15 13:02 ` Peter Zijlstra
2013-10-15 14:32 ` Peter Zijlstra
2013-10-15 15:07 ` Peter Zijlstra
2013-10-15 15:41 ` Don Zickus
2013-10-16 10:57 ` [PATCH] perf, x86: Optimize intel_pmu_pebs_fixup_ip() Peter Zijlstra
2013-10-16 12:46 ` Don Zickus
2013-10-16 13:31 ` Peter Zijlstra
2013-10-16 13:54 ` Don Zickus
2013-10-17 11:21 ` Peter Zijlstra
2013-10-17 13:33 ` Peter Zijlstra
2013-10-29 14:07 ` [tip:perf/urgent] perf/x86: Fix NMI measurements tip-bot for Peter Zijlstra
2013-10-16 20:52 ` [PATCH] perf, x86: Optimize intel_pmu_pebs_fixup_ip() Andi Kleen
2013-10-16 21:03 ` Peter Zijlstra
2013-10-16 23:07 ` Peter Zijlstra
2013-10-17 9:41 ` Peter Zijlstra
2013-10-17 16:00 ` Don Zickus
2013-10-17 16:04 ` Don Zickus
2013-10-17 16:30 ` Peter Zijlstra
2013-10-17 18:26 ` Linus Torvalds
2013-10-17 21:08 ` Peter Zijlstra
2013-10-17 21:11 ` Peter Zijlstra
2013-10-17 22:01 ` Peter Zijlstra
2013-10-17 22:27 ` Linus Torvalds
2013-10-22 21:12 ` Peter Zijlstra
2013-10-23 7:09 ` Linus Torvalds [this message]
2013-10-23 20:48 ` Peter Zijlstra
2013-10-24 10:52 ` Peter Zijlstra
2013-10-24 13:47 ` Don Zickus
2013-10-24 14:06 ` Peter Zijlstra
2013-10-25 16:33 ` Don Zickus
2013-10-25 17:03 ` Peter Zijlstra
2013-10-26 10:36 ` Ingo Molnar
2013-10-28 13:19 ` Don Zickus
2013-10-29 14:08 ` [tip:perf/core] perf/x86: Further optimize copy_from_user_nmi() tip-bot for Peter Zijlstra
2013-10-23 7:44 ` [PATCH] perf, x86: Optimize intel_pmu_pebs_fixup_ip() Ingo Molnar
2013-10-17 14:49 ` Don Zickus
2013-10-17 14:51 ` Peter Zijlstra
2013-10-17 15:03 ` Don Zickus
2013-10-17 15:09 ` Peter Zijlstra
2013-10-17 15:11 ` Peter Zijlstra
2013-10-17 16:50 ` [tip:perf/core] perf/x86: " tip-bot for Peter Zijlstra
2013-10-15 16:22 ` x86, perf: throttling issues with long nmi latencies Don Zickus
2013-10-15 14:36 ` Don Zickus
2013-10-15 14:39 ` Peter Zijlstra
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