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Date: Mon, 7 Dec 2015 11:48:31 -0500
From: Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH v2 1/2] mm: Export nr_swap_pages
Message-ID: <20151207164831.GA7256@cmpxchg.org>
References: <1449244734-25733-1-git-send-email-chris@chris-wilson.co.uk>
 <20151207134812.GA20782@dhcp22.suse.cz>
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To: Michal Hocko <mhocko@kernel.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>, intel-gfx@lists.freedesktop.org, "Goel, Akash" <akash.goel@intel.com>, linux-mm@kvack.org

On Mon, Dec 07, 2015 at 02:48:12PM +0100, Michal Hocko wrote:
> On Fri 04-12-15 15:58:53, Chris Wilson wrote:
> > Some modules, like i915.ko, use swappable objects and may try to swap
> > them out under memory pressure (via the shrinker). Before doing so, they
> > want to check using get_nr_swap_pages() to see if any swap space is
> > available as otherwise they will waste time purging the object from the
> > device without recovering any memory for the system. This requires the
> > nr_swap_pages counter to be exported to the modules.
> 
> I guess it should be sufficient to change get_nr_swap_pages into a real
> function and export it rather than giving the access to the counter
> directly?

What do you mean by "sufficient"? That is actually more work.

It should be sufficient to just export the counter.

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From mboxrd@z Thu Jan  1 00:00:00 1970
From: Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH v2 1/2] mm: Export nr_swap_pages
Date: Mon, 7 Dec 2015 11:48:31 -0500
Message-ID: <20151207164831.GA7256@cmpxchg.org>
References: <1449244734-25733-1-git-send-email-chris@chris-wilson.co.uk>
 <20151207134812.GA20782@dhcp22.suse.cz>
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