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Subject: Re: [PATCH] proc.5: add "wf" to VmFlags in /proc/[pid]/smaps
To:     Ian Rogers <irogers@google.com>, Rik van Riel <riel@redhat.com>
References: <20200521222551.259804-1-irogers@google.com>
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From:   "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
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Date:   Mon, 25 May 2020 15:50:38 +0200
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On 5/22/20 1:13 AM, Ian Rogers wrote:
> On Thu, May 21, 2020 at 3:25 PM Ian Rogers <irogers@google.com> wrote:
>>
>> This patch documents a flag added in the following kernel commit:
>>
>> commit d2cd9ede6e193dd7d88b6d27399e96229a551b19
>> Author: Rik van Riel <riel@redhat.com>
>> Date:   Wed Sep 6 16:25:15 2017 -0700
>>
>>     mm,fork: introduce MADV_WIPEONFORK
>>
>> This was already documented in man2/madvise.2 in the commit:
>>
>> commit c0c4f6c29c494c466f3a2a6273c5b55b76a72927
>> Author: Rik van Riel <riel@redhat.com>
>> Date:   Tue Sep 19 20:32:00 2017 +0200
>>
>>     madvise.2: Document MADV_WIPEONFORK and MADV_KEEPONFORK
>>
>> Signed-off-by: Ian Rogers <irogers@google.com>
> 
> Doing a quick audit of fs/proc/task_mmu.c having noticed this flag was
> missing I note:
>  - "mp" isn't documented, only possible with INTEL_MPX
>  - "nl" is documented but not present in show_smap_vma_flags
>  - "um" and "uw" aren't documented

I took a shot at fixing these:


             mp  - MPX-specific VMA (x86, since Linux 3.19)
             nl  - non-linear mapping (removed in Linux 4.0)
             um  - userfaultfd missing pages tracking (since Linux 4.3)
             uw  - userfaultfd wprotect pages tracking (since Linux 4.3)
             sf  - perform synchronous page faults (since Linux 4.15)

Thanks,

Michael
-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/