Re: perf kmem --page stat and gpf_flags translation

[Veronika Molnarova <vmolnaro@redhat.com>]

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On 11/21/24 16:03, Steven Rostedt wrote:
> On Thu, 21 Nov 2024 14:54:25 +0100 (CET)
> Michael Petlan <mpetlan@redhat.com> wrote:
> 
>> Hello Steve and others,
>>
>> We have found out that perf kmem --page stat sometimes fails like the
>> following:
>>
>> # perf kmem --page stat
>> 0x2aa28 [0x8]: failed to process type: 68 [Operation not permitted]
>> error during process events: -1
>>
>> This seem to happen on s390x KVM machines.
>>
>> When we tried to investigate for the reasons, it seems that the problem
>> is caused by incorrect/unexpected translation of gpf_flags for event
>> kmem:mm_page_alloc.
>>
>> # perf script
>> perf   96553 [003] 100299.663963: kmem:mm_page_alloc: page=0x1a8f9 pfn=0x1a8f9 order=0 migratetype=0 gfp_flags=0x500cc2
>> perf   96553 [003] 100299.663995: kmem:mm_page_alloc: page=0x1bc3f pfn=0x1bc3f order=0 migratetype=0 gfp_flags=0x40cc0
>> perf   96553 [003] 100299.664001: kmem:mm_page_alloc: page=0x1a9d9 pfn=0x1a9d9 order=0 migratetype=0 gfp_flags=0x40cc0
>> perf   96553 [003] 100299.664011: kmem:mm_page_alloc: page=0x1788b pfn=0x1788b order=0 migratetype=0 gfp_flags=0x40cc0
>> perf   96553 [003] 100299.664023: kmem:mm_page_alloc: page=0x17993 pfn=0x17993 order=0 migratetype=0 gfp_flags=0xcc0
>>
> 
> Does the same thing happen with trace-cmd record?
> 
>  # trace-cmd record -e mm_page_alloc
> [ run tests, hit Ctrl^C ]
> 
>  # trace-cmd report
> 
> ?
The trace-cmd report is the same it seems:

    perf-217873 [001] 348026.665461: mm_page_alloc:        page=0x31524d936cd pfn=0x824f5 order=0 migratetype=0 gfp_flags=0x500cc2
    perf-217873 [001] 348026.665471: mm_page_alloc:        page=0x31524e9d49a pfn=0x18c2c2 order=0 migratetype=1 gfp_flags=0x140cca
    perf-217873 [001] 348026.665474: mm_page_alloc:        page=0x31524ea8565 pfn=0x19738d order=0 migratetype=1 gfp_flags=0x140cca
    perf-217873 [001] 348026.665477: mm_page_alloc:        page=0x31524db8925 pfn=0xa774d order=0 migratetype=1 gfp_flags=0x140cca

Sending the trace.dat file as an attachment.

Thanks,
Veronika
> 
> If so, could you send the trace.dat file to me.
> 
> Thanks,
> 
> -- Steve
> 

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