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Date: Wed, 15 May 2013 15:56:01 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Mel Gorman <mgorman@suse.de>
Cc: Alexey Lyahkov <alexey.lyashkov@gmail.com>,
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Subject: Re: [PATCH 4/4] mm: Remove lru parameter from __pagevec_lru_add and
 remove parts of pagevec API
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On Mon, 13 May 2013 11:21:22 +0100 Mel Gorman <mgorman@suse.de> wrote:

> Now that the LRU to add a page to is decided at LRU-add time, remove the
> misleading lru parameter from __pagevec_lru_add. A consequence of this is
> that the pagevec_lru_add_file, pagevec_lru_add_anon and similar helpers
> are misleading as the caller no longer has direct control over what LRU
> the page is added to. Unused helpers are removed by this patch and existing
> users of pagevec_lru_add_file() are converted to use lru_cache_add_file()
> directly and use the per-cpu pagevecs instead of creating their own pagevec.

Well maybe.  The `lru' arg to __lru_cache_add is still there and is
rather misleading (I find it maddening ;)).  AIUI, it's just there as
the means by which the __lru_cache_add() caller tells the LRU manager
that the caller wishes this page to start life on the active LRU, yes? 
It doesn't _really_ specify an LRU list at all.

In which case I think it would be a heck of a lot clearer if the
callers were to do

	SetPageActve(page);
	__lru_cache_add(page);

no?  (Or __lru_cache_add_active(page) and
__lru_cache_add_inactive(page) if one prefers).

Ditto lru_cache_add_lru() and probably other things.  Let's have one
way of communicating activeness, not two.