Re: [LTP] [PATCH v2] syscalls/mlock05: add mlock test for locking and pre-faulting of memory

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> After some investigation, I realized the issue is caused by the
> unreliability of the VmRSS field in /proc/$pid/status.
> Documentation suggests to use /proc/$pid/smaps for reliable information.
> 
> This file contains information about each memory mapping, so it contains
> multiple instances of the VmRss field (In this file is simply referred as
> Rss).
> 
> I managed to run the test without any failures using a custom function.
> What we need to do is to iterate through the memory mappings until we find
> the one we need. We can use the memory address retrieved by mmap to locate
> the desired one.
> 
> Once we find the mapping, we can then search the Rss field.
> 
> This is the output I had using this approach:
> 
> TPASS: Expect: (VmRSS=1048576) >= (MMAPLEN=1048576)
> TPASS: VmLck == MMAPLEN (1048576)
> 
> Summary:
> passed  20000
> failed   0
> broken   0
> skipped  0
> warnings 0
> 
> Do you think this can work as a solution or you prefer another way around?

Looking up the right mapping and checking that the size of the resident
set is as expected sounds good to me.

-- 
Cyril Hrubis
chrubis@suse.cz

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