From: "Liang, Kan" <kan.liang@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
acme@kernel.org, mingo@redhat.com, linux-kernel@vger.kernel.org,
eranian@google.com, jolsa@redhat.com, namhyung@kernel.org,
ak@linux.intel.com, Andy Lutomirski <luto@amacapital.net>
Subject: Re: [PATCH V3 01/13] perf/core, x86: Add PERF_SAMPLE_DATA_PAGE_SIZE
Date: Fri, 8 Feb 2019 08:35:04 -0500 [thread overview]
Message-ID: <63b27cde-294e-056d-3ac5-3778c27cfb09@linux.intel.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1902081138050.1595@nanos.tec.linutronix.de>
On 2/8/2019 5:39 AM, Thomas Gleixner wrote:
> On Thu, 31 Jan 2019, Liang, Kan wrote:
>>>> +u64 perf_get_page_size(u64 virt)
>>>> +{
>>>> + unsigned long flags;
>>>> + unsigned int level;
>>>> + pte_t *pte;
>>>> +
>>>> + if (!virt)
>>>> + return 0;
>>>> +
>>>> + /*
>>>> + * Interrupts are disabled, so it prevents any tear down
>>>> + * of the page tables.
>>>> + * See the comment near struct mmu_table_batch.
>>>> + */
>>>> + local_irq_save(flags);
>>>> + if (virt >= TASK_SIZE)
>>>> + pte = lookup_address(virt, &level);
>>>> + else {
>>>> + if (current->mm)
>>>> + pte = lookup_address_in_pgd(pgd_offset(current->mm,
>>>> virt),
>>>> + virt, &level);
>>>
>>> Aside from all the missin {}, I'm fairly sure this is broken since this
>>> happens from NMI context. This can interrupt switch_mm() and things like
>>> use_temporary_mm().
>>>
>>> Also; why does this live in the x86 code and not in the generic code?
>>>
>>
>> This is x86 implementation.
>> In generic code, there is a __weak function. I'll make it clear in the change
>> log in v4.
>
> No, instead of hiding it in the changelog, split the patch into two:
>
> #1 Adding the core stuff including the weak function
>
> #2 Adding the x86 implementation.
>
Thanks for the comments. I will do it in V5.
Thanks,
Kan
next prev parent reply other threads:[~2019-02-08 13:35 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-30 14:23 [PATCH V3 01/13] perf/core, x86: Add PERF_SAMPLE_DATA_PAGE_SIZE kan.liang
2019-01-30 14:23 ` [PATCH V3 02/13] perf tools: Support new sample type for data page size kan.liang
2019-01-30 14:23 ` [PATCH V3 03/13] perf script: Support " kan.liang
2019-01-30 14:23 ` [PATCH V3 04/13] perf sort: Add sort option for " kan.liang
2019-01-30 14:23 ` [PATCH V3 05/13] perf mem: Factor out a function to generate sort order kan.liang
2019-01-30 14:23 ` [PATCH V3 06/13] perf mem: Clean up output format kan.liang
2019-01-30 14:23 ` [PATCH V3 07/13] perf mem: Support data page size kan.liang
2019-01-30 14:23 ` [PATCH V3 08/13] perf test: Add test case for PERF_SAMPLE_DATA_PAGE_SIZE kan.liang
2019-01-30 14:23 ` [PATCH V3 09/13] perf/core, x86: Add support for PERF_SAMPLE_CODE_PAGE_SIZE kan.liang
2019-01-30 14:23 ` [PATCH V3 10/13] perf tools: " kan.liang
2019-01-30 14:23 ` [PATCH V3 11/13] perf script: " kan.liang
2019-01-30 14:23 ` [PATCH V3 12/13] perf report: " kan.liang
2019-01-30 14:23 ` [PATCH V3 13/13] perf test: Add test case " kan.liang
2019-01-31 12:37 ` [PATCH V3 01/13] perf/core, x86: Add PERF_SAMPLE_DATA_PAGE_SIZE Peter Zijlstra
2019-01-31 12:59 ` Peter Zijlstra
2019-01-31 13:10 ` Andi Kleen
2019-01-31 14:58 ` Liang, Kan
2019-02-08 10:39 ` Thomas Gleixner
2019-02-08 13:35 ` Liang, Kan [this message]
2019-02-01 5:02 ` Will Deacon
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