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| author |   Dmitry Osipenko <dmitry.osipenko@collabora.com> | 2022-11-04 19:04:59 +0300 |
|---|---|---|
| committer | Dmitry Osipenko <dmitry.osipenko@collabora.com> | 2023-02-27 07:06:56 +0300 |
| commit | 9630b585b607bd26f505d34620b14d75b9a5af7d (patch) | |
| tree | 46eb1c8f9016be79477886fc966a5b6ce4480544 /include/drm/drm_gem.h | |
| parent | drm/shmem-helper: Remove another errant put in error path (diff) | |
| download | wireguard-linux-9630b585b607bd26f505d34620b14d75b9a5af7d.tar.xz wireguard-linux-9630b585b607bd26f505d34620b14d75b9a5af7d.zip | |
drm/msm/gem: Prevent blocking within shrinker loop
Consider this scenario:
1. APP1 continuously creates lots of small GEMs
2. APP2 triggers `drop_caches`
3. Shrinker starts to evict APP1 GEMs, while APP1 produces new purgeable
GEMs
4. msm_gem_shrinker_scan() returns non-zero number of freed pages
and causes shrinker to try shrink more
5. msm_gem_shrinker_scan() returns non-zero number of freed pages again,
goto 4
6. The APP2 is blocked in `drop_caches` until APP1 stops producing
purgeable GEMs
To prevent this blocking scenario, check number of remaining pages
that GPU shrinker couldn't release due to a GEM locking contention
or shrinking rejection. If there are no remaining pages left to shrink,
then there is no need to free up more pages and shrinker may break out
from the loop.
This problem was found during shrinker/madvise IOCTL testing of
virtio-gpu driver. The MSM driver is affected in the same way.
Reviewed-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: b352ba54a820 ("drm/msm/gem: Convert to using drm_gem_lru")
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://lore.kernel.org/all/20230108210445.3948344-2-dmitry.osipenko@collabora.com/
Diffstat (limited to 'include/drm/drm_gem.h')
| -rw-r--r-- | include/drm/drm_gem.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h index a17c2f903f81..b46ade812443 100644 --- a/include/drm/drm_gem.h +++ b/include/drm/drm_gem.h @@ -475,7 +475,9 @@ int drm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev, void drm_gem_lru_init(struct drm_gem_lru *lru, struct mutex *lock); void drm_gem_lru_remove(struct drm_gem_object *obj); void drm_gem_lru_move_tail(struct drm_gem_lru *lru, struct drm_gem_object *obj); -unsigned long drm_gem_lru_scan(struct drm_gem_lru *lru, unsigned nr_to_scan, +unsigned long drm_gem_lru_scan(struct drm_gem_lru *lru, + unsigned int nr_to_scan, + unsigned long *remaining, bool (*shrink)(struct drm_gem_object *obj)); #endif /* __DRM_GEM_H__ */ |