Re: [PATCH] mm, page_alloc: skip zone who has no managed_pages in calculate_totalreserve_pages()

[Wei Yang <richard.weiyang@gmail.com>]

On Tue, Nov 13, 2018 at 10:07:58AM +0100, Michal Hocko wrote:
>On Tue 13-11-18 08:16:44, Wei Yang wrote:
>
>No, I believe we want all three of them. But reviewing
>for_each_populated_zone users and explicit checks for present/managed
>pages and unify them would be a step forward both a more optimal code
>and more maintainable code. I haven't checked but
>for_each_populated_zone would seem like a proper user for managed page
>counter. But that really requires to review all current users.
>

To sync with your purpose, I searched the user of
for_each_populated_zone() and replace it with a new loop
for_each_managed_zone().

Here is a summary of what I have done.

file                          used     changed
----------------------------------------------
arch/s390/mm/page-states.c    1        1
kernel/power/snapshot.c       7        3
mm/highmem.c                  1        1
mm/huge_memory.c              1        0
mm/khugepaged.c               1        1
mm/madvise.c                  1        1
mm/page_alloc.c               8        8
mm/vmstat.c                   5        5

The general idea to replace for_each_populated_zone() with
for_each_populated_zone() is:

   * access zone->freelist
   * access zone pcp
   * access zone_page_state

Is my understanding comply with what you want? 

>-- 
>Michal Hocko
>SUSE Labs

-- 
Wei Yang
Help you, Help me