From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f53.google.com (mail-wm0-f53.google.com [74.125.82.53]) by kanga.kvack.org (Postfix) with ESMTP id 0D5326B0005 for ; Tue, 5 Jan 2016 05:05:31 -0500 (EST) Received: by mail-wm0-f53.google.com with SMTP id f206so16693449wmf.0 for ; Tue, 05 Jan 2016 02:05:31 -0800 (PST) Received: from mail-wm0-x22d.google.com (mail-wm0-x22d.google.com. [2a00:1450:400c:c09::22d]) by mx.google.com with ESMTPS id u131si4225753wmb.69.2016.01.05.02.05.29 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 05 Jan 2016 02:05:29 -0800 (PST) Received: by mail-wm0-x22d.google.com with SMTP id f206so16692908wmf.0 for ; Tue, 05 Jan 2016 02:05:29 -0800 (PST) Date: Tue, 5 Jan 2016 11:05:27 +0100 From: Daniel Vetter Subject: Re: [Intel-gfx] [PATCH v2 1/2] mm: Export nr_swap_pages Message-ID: <20160105100527.GO8076@phenom.ffwll.local> References: <1449244734-25733-1-git-send-email-chris@chris-wilson.co.uk> <20151204160952.GA24927@cmpxchg.org> <20151210093242.GH20822@phenom.ffwll.local> <20151223220427.GA11412@cmpxchg.org> <20151223142611.63907890.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151223142611.63907890.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Johannes Weiner , Daniel Vetter , Chris Wilson , linux-mm@kvack.org, intel-gfx@lists.freedesktop.org, "Goel, Akash" On Wed, Dec 23, 2015 at 02:26:11PM -0800, Andrew Morton wrote: > On Wed, 23 Dec 2015 17:04:27 -0500 Johannes Weiner wrote: > > > On Thu, Dec 10, 2015 at 10:32:42AM +0100, Daniel Vetter wrote: > > > On Fri, Dec 04, 2015 at 11:09:52AM -0500, Johannes Weiner wrote: > > > > On Fri, Dec 04, 2015 at 03:58:53PM +0000, 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. > > > > > > > > > > Signed-off-by: Chris Wilson > > > > > Cc: "Goel, Akash" > > > > > Cc: Johannes Weiner > > > > > Cc: linux-mm@kvack.org > > > > > > > > Acked-by: Johannes Weiner > > > > > > Ack for merging this through drm-intel trees for 4.5? I'm a bit unclear > > > who's ack I need for that for linux-mm topics ... > > > > Andrew would be the -mm maintainer. CC'd. > > yup, please go ahead and merge that via the DRM tree. > > nr_swap_pages is a crappy name. That means "number of pages in swap", > which isn't the case. Something like "swap_pages_available" would be > better. > > And your swap_available() isn't good either ;) It can mean "is any swap > online" or "what is the amount of free swap space (in unknown units!)". > I'd call it "swap_is_full()" and put a ! in the caller. But it's > hardly important for a wee little static helper. Yeah it's not super-pretty, but then the entire core mm/shrinker abstraction is more than just a bit leaky (at least i915 has plenty of code to make sure we don't bite our own tail). In case of doubt I prefer the simplest export and avoid the mistake of fake abstraction in the form of an inline helper with a pretty name. Merged to drm-intel.git as-is, but missed the 4.5 train so will only land in 4.6. Thanks, Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org