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Date: Tue, 6 Nov 2018 10:08:39 +0100
From: Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH v5] mm, drm/i915: mark pinned shmemfs pages as unevictable
Message-ID: <20181106090839.GE27423@dhcp22.suse.cz>
References: <20181106090352.64114-1-vovoy@chromium.org>
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In-Reply-To: <20181106090352.64114-1-vovoy@chromium.org>
Sender: owner-linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>
To: Kuo-Hsin Yang <vovoy@chromium.org>
Cc: linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-mm@kvack.org, Chris Wilson <chris@chris-wilson.co.uk>, Joonas Lahtinen <joonas.lahtinen@linux.intel.com>, Peter Zijlstra <peterz@infradead.org>, Andrew Morton <akpm@linux-foundation.org>, Dave Hansen <dave.hansen@intel.com>

On Tue 06-11-18 17:03:51, Kuo-Hsin Yang wrote:
> The i915 driver uses shmemfs to allocate backing storage for gem
> objects. These shmemfs pages can be pinned (increased ref count) by
> shmem_read_mapping_page_gfp(). When a lot of pages are pinned, vmscan
> wastes a lot of time scanning these pinned pages. In some extreme case,
> all pages in the inactive anon lru are pinned, and only the inactive
> anon lru is scanned due to inactive_ratio, the system cannot swap and
> invokes the oom-killer. Mark these pinned pages as unevictable to speed
> up vmscan.
> 
> Export pagevec API check_move_unevictable_pages().
> 
> This patch was inspired by Chris Wilson's change [1].
> 
> [1]: https://patchwork.kernel.org/patch/9768741/
> 
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Dave Hansen <dave.hansen@intel.com>
> Signed-off-by: Kuo-Hsin Yang <vovoy@chromium.org>
> Acked-by: Michal Hocko <mhocko@suse.com>

please make it explicit that the ack applies to mm part as i've
mentioned when giving my ack to the previous version.

E.g.
Acked-by: Michal Hocko <mhocko@use.com> # mm part

because i am not familiar with the drm code to ack any changes there.
-- 
Michal Hocko
SUSE Labs