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mm, drm/i915: mark pinned shmemfs pages as unevictable

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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> # mm part
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20181106132324.17390-1-chris@chris-wilson.co.uk
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
This commit is contained in:
Kuo-Hsin Yang
2018-11-06 13:23:24 +00:00
committed by Chris Wilson
parent f45a7977d1
commit 64e3d12f76
5 changed files with 49 additions and 18 deletions
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6
Documentation/vm/unevictable-lru.rst
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@@ -143,7 +143,7 @@ using a number of wrapper functions:
Query the address space, and return true if it is completely
unevictable.
These are currently used in two places in the kernel:
These are currently used in three places in the kernel:
(1) By ramfs to mark the address spaces of its inodes when they are created,
and this mark remains for the life of the inode.
@@ -154,6 +154,10 @@ These are currently used in two places in the kernel:
swapped out; the application must touch the pages manually if it wants to
ensure they're in memory.
(3) By the i915 driver to mark pinned address space until it's unpinned. The
amount of unevictable memory marked by i915 driver is roughly the bounded
object size in debugfs/dri/0/i915_gem_objects.
Detecting Unevictable Pages
---------------------------