Re: [patch] vmscan: rename sc.may_swap to may_unmap

[MinChan Kim <minchan.kim@gmail.com>]

On Tue, Feb 10, 2009 at 4:43 AM, Johannes Weiner <hannes@cmpxchg.org> wrote:
> sc.may_swap does not only influence reclaiming of anon pages but pages
> mapped into pagetables in general, which also includes mapped file
> pages.
>
> From shrink_page_list():
>
>                if (!sc->may_swap && page_mapped(page))
>                        goto keep_locked;
>
> For anon pages, this makes sense as they are always mapped and
> reclaiming them always requires swapping.
>
> But mapped file pages are skipped here as well and it has nothing to
> do with swapping.
>
> The real effect of the knob is whether mapped pages are unmapped and
> reclaimed or not.  Rename it to `may_unmap' to have its name match its
> actual meaning more precisely.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> ---
>  mm/vmscan.c |   20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
>
> On Sat, Feb 07, 2009 at 02:15:21AM +0900, MinChan Kim wrote:
>> Sorry for misunderstood your point.
>> It would be better to remain more detaily for git log ?
>>
>> 'may_swap' applies not only to anon pages but to mapped file pages as
>> well. 'may_swap' term is sometime used for 'swap', sometime used for
>> 'sync|discard'.
>> In case of anon pages, 'may_swap' determines whether pages were swapout or not.
>> but In case of mapped file pages, it determines whether pages are
>> synced or discarded. so, 'may_swap' is rather awkward. Rename it to
>> 'may_unmap' which is the actual meaning.
>>
>> If you find wrong word and sentence, Please, fix it. :)
>
> Is the above description okay for you?
>

It looks good to me. :)

Reviewed-by: MinChan Kim <minchan.kim@gmail.com>

-- 
Kinds regards,
MinChan Kim

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