From 9630b585b607bd26f505d34620b14d75b9a5af7d Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Fri, 4 Nov 2022 19:04:59 +0300 Subject: 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 Reviewed-by: Thomas Zimmermann Fixes: b352ba54a820 ("drm/msm/gem: Convert to using drm_gem_lru") Signed-off-by: Dmitry Osipenko Link: https://lore.kernel.org/all/20230108210445.3948344-2-dmitry.osipenko@collabora.com/ --- include/drm/drm_gem.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include/drm') 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__ */ -- cgit v1.2.3-70-g09d2 From 0d3c9333d976af41d7dbc6bf4d9d2e95fbdf9c89 Mon Sep 17 00:00:00 2001 From: Liu Ying Date: Tue, 14 Mar 2023 13:50:35 +0800 Subject: drm/bridge: Fix returned array size name for atomic_get_input_bus_fmts kdoc The returned array size for input formats is set through atomic_get_input_bus_fmts()'s 'num_input_fmts' argument, so use 'num_input_fmts' to represent the array size in the function's kdoc, not 'num_output_fmts'. Fixes: 91ea83306bfa ("drm/bridge: Fix the bridge kernel doc") Fixes: f32df58acc68 ("drm/bridge: Add the necessary bits to support bus format negotiation") Signed-off-by: Liu Ying Reviewed-by: Robert Foss Signed-off-by: Neil Armstrong Link: https://patchwork.freedesktop.org/patch/msgid/20230314055035.3731179-1-victor.liu@nxp.com --- include/drm/drm_bridge.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/drm') diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index 42f86327b40a..bf964cdfb330 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -423,11 +423,11 @@ struct drm_bridge_funcs { * * The returned array must be allocated with kmalloc() and will be * freed by the caller. If the allocation fails, NULL should be - * returned. num_output_fmts must be set to the returned array size. + * returned. num_input_fmts must be set to the returned array size. * Formats listed in the returned array should be listed in decreasing * preference order (the core will try all formats until it finds one * that works). When the format is not supported NULL should be - * returned and num_output_fmts should be set to 0. + * returned and num_input_fmts should be set to 0. * * This method is called on all elements of the bridge chain as part of * the bus format negotiation process that happens in -- cgit v1.2.3-70-g09d2