Re: [PATCH] mm: move swap-in anonymous page into active list

From: Rik van Riel
Date: Fri Jul 29 2016 - 12:55:45 EST


On Fri, 2016-07-29 at 12:25 +0900, Minchan Kim wrote:
> Every swap-in anonymous page starts from inactive lru list's head.
> It should be activated unconditionally when VM decide to reclaim
> because page table entry for the page always usually has marked
> accessed bit. Thus, their window size for getting a new referece
> is 2 * NR_inactive + NR_active while others is NR_active + NR_active.
>
> It's not fair that it has more chance to be referenced compared
> to other newly allocated page which starts from active lru list's
> head.
>
> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>

Acked-by: Rik van Riel <riel@xxxxxxxxxx>

The reason newly read in swap cache pages start on the
inactive list is that we do some amount of read-around,
and do not know which pages will get used.

However, immediately activating the ones that DO get
used, like your patch does, is the right thing to do.

--Â
All Rights Reversed.

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