Messages in this thread | | | From | Song Liu <> | Subject | Re: [PATCH] perf: rework memory accounting in perf_mmap() | Date | Mon, 30 Sep 2019 05:33:52 +0000 |
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> On Sep 16, 2019, at 1:10 PM, Hechao Li <hechaol@fb.com> wrote: > > Song Liu <songliubraving@fb.com> wrote on Mon [2019-Sep-16 12:43:16 -0700]: >> Hi Peter, >> >>> On Sep 4, 2019, at 2:46 PM, Song Liu <songliubraving@fb.com> wrote: >>> >>> perf_mmap() always increases user->locked_vm. As a result, "extra" could >>> grow bigger than "user_extra", which doesn't make sense. Here is an >>> example case: >>> >>> Note: Assume "user_lock_limit" is very small. >>> | # of perf_mmap calls |vma->vm_mm->pinned_vm|user->locked_vm| >>> | 0 | 0 | 0 | >>> | 1 | user_extra | user_extra | >>> | 2 | 3 * user_extra | 2 * user_extra| >>> | 3 | 6 * user_extra | 3 * user_extra| >>> | 4 | 10 * user_extra | 4 * user_extra| >>> >>> Fix this by maintaining proper user_extra and extra. >>> >>> Reported-by: Hechao Li <hechaol@fb.com> >>> Cc: Jie Meng <jmeng@fb.com> >>> Cc: Peter Zijlstra <peterz@infradead.org> >>> Signed-off-by: Song Liu <songliubraving@fb.com> >> >> Could you please share your feedbacks/comments on this one? >> >> Thanks, >> Song > > The change looks good to me. Thanks, Song. > > Reviewed-By: Hechao Li <hechaol@fb.com>
Thanks Hechao!
Hi Peter,
Does this fix look good to you?
Thanks, Song
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