From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 6646B6B04CF for ; Mon, 21 Aug 2017 10:06:46 -0400 (EDT) Received: by mail-wr0-f198.google.com with SMTP id y44so27552659wrd.13 for ; Mon, 21 Aug 2017 07:06:46 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id m138si2904913wmg.263.2017.08.21.07.06.44 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 21 Aug 2017 07:06:44 -0700 (PDT) Date: Mon, 21 Aug 2017 16:06:42 +0200 From: Michal Hocko Subject: Re: [RFC] mm,drm/i915: Mark pinned shmemfs pages as unevictable Message-ID: <20170821140641.GN25956@dhcp22.suse.cz> References: <20170606120436.8683-1-chris@chris-wilson.co.uk> <20170606121418.GM1189@dhcp22.suse.cz> <150314853540.7354.10275185301153477504@mail.alporthouse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <150314853540.7354.10275185301153477504@mail.alporthouse.com> Sender: owner-linux-mm@kvack.org List-ID: To: Chris Wilson Cc: intel-gfx@lists.freedesktop.org, linux-mm@kvack.org, Joonas Lahtinen , Matthew Auld , Dave Hansen , "Kirill A . Shutemov" , Andrew Morton , Peter Zijlstra On Sat 19-08-17 14:15:35, Chris Wilson wrote: > Quoting Michal Hocko (2017-06-06 13:14:18) > > On Tue 06-06-17 13:04:36, Chris Wilson wrote: > > > Similar in principle to the treatment of get_user_pages, pages that > > > i915.ko acquires from shmemfs are not immediately reclaimable and so > > > should be excluded from the mm accounting and vmscan until they have > > > been returned to the system via shrink_slab/i915_gem_shrink. By moving > > > the unreclaimable pages off the inactive anon lru, not only should > > > vmscan be improved by avoiding walking unreclaimable pages, but the > > > system should also have a better idea of how much memory it can reclaim > > > at that moment in time. > > > > That is certainly desirable. Peter has proposed a generic pin_page (or > > similar) API. What happened with it? I think it would be a better > > approach than (ab)using mlock API. I am also not familiar with the i915 > > code to be sure that using lock_page is really safe here. I think that > > all we need is to simply move those pages in/out to/from unevictable LRU > > list on pin/unpining. > > I just had the opportunity to try this mlock_vma_page() hack on a > borderline swapping system (i.e. lots of vmpressure between i915 buffers > and the buffercache), and marking the i915 pages as unevictable makes a > huge difference in avoiding stalls in direct reclaim across the system. > > Reading back over the thread, it seems that the simplest approach going > forward is a small api for managing the pages on the unevictable LRU? Yes and I thought that pin_page API would do exactly that. -- Michal Hocko SUSE Labs -- 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