Re: why are some low-level MM routines being exported?

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

On Mon, Apr 5, 2010 at 3:15 AM, Evgeniy Polyakov <zbr@ioremap.net> wrote:
> On Mon, Apr 05, 2010 at 01:21:52AM +0900, Minchan Kim (minchan.kim@gmail.com) wrote:
>> > > It is added by 18bc0bbd162e3 for pohmelfs and now used by logfs, too.
>> > > I didn't noticed that at that time.
>> > > With git log, any mm guys didn't add Signed-off-by or Reviewed-by.
>> > >
>> > > I think it's not good for file system or module to use it directly.
>> > > It would make LRU management harder.
>> >
>> > How come?
>>
>> What I have a concern is that if file systems or some modules start to
>> overuse it to manage pages LRU directly, some mistake of them would make
>> system global LRU stupid and make system wrong.
>
> All filesystems already call it through find_or_create_page() or
> grab_page() invoked via read path. In some cases fs has more than
> one page grabbed via its internal path where data to be read is
> already placed, so it may want just to add those pages into mm lru.
>

I understood why it does need that in pohmelfs.
AFAIU, other file system using general functions(ex, mpage_readpages or
read_cache_pages) don't need direct LRU handling since it's hided.
But pohmelfs doesn't use general functions.

Isn't pagevec_lru_add_file enough like other file system(ex, nfs, cifs)?

-- 
Kind regards,
Minchan Kim

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