Messages in this thread | | | From | Alexander Shishkin <> | Subject | Re: [PATCH] perf/core: fix mlock accounting in perf_mmap() | Date | Thu, 23 Jan 2020 11:19:44 +0200 |
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Song Liu <songliubraving@fb.com> writes:
>> On Jan 20, 2020, at 12:24 AM, Alexander Shishkin <alexander.shishkin@linux.intel.com> wrote: >> >> Song Liu <songliubraving@fb.com> writes: >> >>> sysctl_perf_event_mlock and user->locked_vm can change value >>> independently, so we can't guarantee: >>> >>> user->locked_vm <= user_lock_limit >> >> This means: if the sysctl got sufficiently decreased, so that the >> existing locked_vm exceeds it, we need to deal with the overflow, right? > > Reducing sysctl is one way to generate the overflow. Another way is to > call setrlimit() from user space to allow bigger user->locked_vm.
You mean RLIMIT_MEMLOCK? That's a limit on mm->pinned_vm. Doesn't affect user->locked_vm.
Regards, -- Alex
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