Re: [PATCH 05/10] mm: remove LRU balancing effect of temporary page isolation

From: Johannes Weiner <hannes@cmpxchg.org>
To: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Mel Gorman <mgorman@suse.de>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andi Kleen <andi@firstfloor.org>, Michal Hocko <mhocko@suse.cz>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	kernel-team@fb.com
Subject: Re: [PATCH 05/10] mm: remove LRU balancing effect of temporary page isolation
Date: Mon, 6 Jun 2016 18:15:50 -0400	[thread overview]
Message-ID: <20160606221550.GA6665@cmpxchg.org> (raw)
In-Reply-To: <1465250169.16365.147.camel@redhat.com>

On Mon, Jun 06, 2016 at 05:56:09PM -0400, Rik van Riel wrote:
> On Mon, 2016-06-06 at 15:48 -0400, Johannes Weiner wrote:
> > 
> > +void lru_cache_putback(struct page *page)
> > +{
> > +	struct pagevec *pvec = &get_cpu_var(lru_putback_pvec);
> > +
> > +	get_page(page);
> > +	if (!pagevec_space(pvec))
> > +		__pagevec_lru_add(pvec, false);
> > +	pagevec_add(pvec, page);
> > +	put_cpu_var(lru_putback_pvec);
> > +}
> > 
> 
> Wait a moment.
> 
> So now we have a putback_lru_page, which does adjust
> the statistics, and an lru_cache_putback which does
> not?
> 
> This function could use a name that is not as similar
> to its counterpart :)

lru_cache_add() and lru_cache_putback() are the two sibling functions,
where the first influences the LRU balance and the second one doesn't.

The last hunk in the patch (obscured by showing the label instead of
the function name as context) updates putback_lru_page() from using
lru_cache_add() to using lru_cache_putback().

Does that make sense?