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From: Peter Zijlstra <peterz@infradead.org>
To: Don Zickus <dzickus@redhat.com>
Cc: dave.hansen@linux.intel.com, eranian@google.com,
	ak@linux.intel.com, jmario@redhat.com,
	linux-kernel@vger.kernel.org, acme@infradead.org
Subject: Re: x86, perf: throttling issues with long nmi latencies
Date: Tue, 15 Oct 2013 16:39:31 +0200	[thread overview]
Message-ID: <20131015143931.GN10651@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20131015143631.GZ227855@redhat.com>

On Tue, Oct 15, 2013 at 10:36:31AM -0400, Don Zickus wrote:
> > > +refill:
> > > +	if (kernel_ip(ip)) {
> > > +		u8 *buf = &__get_cpu_var(insn_page[0]);
> > > +		size = PAGE_SIZE - ((unsigned long)to & (PAGE_SIZE-1));
> > > +		if (size < MAX_INSN_SIZE) {
> > > +			/*
> > > +			 * If we're going to have to touch two pages; just copy
> > > +			 * as much as we can hold.
> > > +			 */
> > > +			size = PAGE_SIZE;

> Quick thoughts?

Yeah, see the patch I just send; but notably I got the kernel_ip(ip)
case the wrong way about. See how it copies userspace memory for kernel
IPs and vice versa.



      reply	other threads:[~2013-10-15 14:39 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
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 [this message]

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