Re: Why sometimes count vm event with page number, sometimes not?

[Wei Yang <richardw.yang@linux.intel.com>]

On Mon, Nov 04, 2019 at 07:32:51PM -0800, Matthew Wilcox wrote:
>On Tue, Nov 05, 2019 at 10:26:44AM +0800, Wei Yang wrote:
>> Hi, All,
>> 
>> I am curious about the semantic of __count_vm_event[s].
>> 
>> For example, we count PGDEACTIVATE event in lru_deactivate_file_fn() and
>> lru_deactivate_fn(). One of them count with number of page, the other not.
>> 
>> Just curious about the exact value we want to count.
>
>I don't understand the question.  We deactivate one page
>in lru_deactivate_file_fn().  We deactivate several pages in
>shrink_active_list().  PGDEACTIVATE counts the number of pages which
>have been deactivated.
>
>Does that answer your question?

Not yet.

In function, lru_deactivate_fn(), __count_vm_events's second parameter is
hpage_nr_pages(page). This is the number in size of "normal" page. Per my
understanding, the page deactivated in lru_deactivate_file_fn() could be a
hpage too. But it just count the deactivation once instead of
hpage_nr_pages().

Or you want to say the page deactivated in lru_deactivate_file_fn() must be an
order 0 page?

-- 
Wei Yang
Help you, Help me