lkml.org 
[lkml]   [2014]   [Jul]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: Where in the code mmap + MAP_ANONYMOUS clears returned pages?
Thanks, Michal!
--
With best regards / с наилучшими пожеланиями,
Alexei Fedotov / Алексей Федотов,
http://dataved.ru/
+7 916 562 8095

[1] Start using Apache Openmeetings today, http://openmeetings.apache.org/
[2] Join Alexei Fedotov @linkedin, http://ru.linkedin.com/in/dataved/
[3] Join Alexei Fedotov @facebook, http://www.facebook.com/openmeetings


On Tue, Jul 15, 2014 at 11:14 PM, Michal Hocko <mhocko@suse.cz> wrote:
> On Tue 15-07-14 21:55:03, Alexei Fedotov wrote:
>> Guys,
>>
>> I look into mmap.c code [1] and try to understand where anonymous
>> memory mapping (mmap + MAP_ANONYMOUS) sets memory to zero. My best
>> guess is I should dig that somewhere in mmap_region.
>>
>> Could you please help me locating the code which makes returned memory
>> pages clean? Thank you in advance.
>
> mmap doesn't allocate pages which back the mapping directly unless it is
> told to by MAP_POPULATE. So the clean pages are either allocated during
> the page fault path when the memory is accessed (see do_anonymous_page
> for private 4k pages fault, do_huge_pmd_anonymous_page for THP page and
> MAP_SHARED is left as an excercise for the reader ;)) or in mmap path
> directly when MAP_POPULATE is specified (see vm_mmap_pgoff which calls
> mm_populate)
>
>>
>> [1] http://code.ohloh.net/file?fid=RPa2fuiQ5j_IwR1nymptYBBC3X4&cid=w6qrXNDsMqk
>>
>> --
>> With best regards / с наилучшими пожеланиями,
>> Alexei Fedotov / Алексей Федотов,
>> http://dataved.ru/
>> +7 916 562 8095
>>
>> [1] Start using Apache Openmeetings today, http://openmeetings.apache.org/
>> [2] Join Alexei Fedotov @linkedin, http://ru.linkedin.com/in/dataved/
>> [3] Join Alexei Fedotov @facebook, http://www.facebook.com/openmeetings
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at http://www.tux.org/lkml/
>
> --
> Michal Hocko
> SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2014-07-16 09:01    [W:0.053 / U:0.336 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site