From 63f17ef834284d9a1fa72b548a86fee1ccd01a45 Mon Sep 17 00:00:00 2001 From: Rob Clark Date: Mon, 5 Apr 2021 10:45:31 -0700 Subject: [PATCH] drm/msm: Support evicting GEM objects to swap Now that tracking is wired up for potentially evictable GEM objects, wire up shrinker and the remaining GEM bits for unpinning backing pages of inactive objects. Disabled by default for now, with an 'enable_eviction' module param to enable so that we can get some more testing on the range of generations (and iommu pairings) supported. Signed-off-by: Rob Clark Link: https://lore.kernel.org/r/20210405174532.1441497-9-robdclark@gmail.com Signed-off-by: Rob Clark --- drivers/gpu/drm/msm/msm_gem.c | 23 +++++++++++++++++++ drivers/gpu/drm/msm/msm_gem_shrinker.c | 40 +++++++++++++++++++++++++++++++++- drivers/gpu/drm/msm/msm_gpu_trace.h | 13 +++++++++++ 3 files changed, 75 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c index f0cd8b9..b199942 100644 --- a/drivers/gpu/drm/msm/msm_gem.c +++ b/drivers/gpu/drm/msm/msm_gem.c @@ -759,6 +759,29 @@ void msm_gem_purge(struct drm_gem_object *obj) 0, (loff_t)-1); } +/** + * Unpin the backing pages and make them available to be swapped out. + */ +void msm_gem_evict(struct drm_gem_object *obj) +{ + struct drm_device *dev = obj->dev; + struct msm_gem_object *msm_obj = to_msm_bo(obj); + + GEM_WARN_ON(!msm_gem_is_locked(obj)); + GEM_WARN_ON(is_unevictable(msm_obj)); + GEM_WARN_ON(!msm_obj->evictable); + GEM_WARN_ON(msm_obj->active_count); + + /* Get rid of any iommu mapping(s): */ + put_iova_spaces(obj, false); + + drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping); + + put_pages(obj); + + update_inactive(msm_obj); +} + void msm_gem_vunmap(struct drm_gem_object *obj) { struct msm_gem_object *msm_obj = to_msm_bo(obj); diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c index a4d8595..1187ecf 100644 --- a/drivers/gpu/drm/msm/msm_gem_shrinker.c +++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c @@ -9,12 +9,29 @@ #include "msm_gpu.h" #include "msm_gpu_trace.h" +/* Default disabled for now until it has some more testing on the different + * iommu combinations that can be paired with the driver: + */ +bool enable_eviction = false; +MODULE_PARM_DESC(enable_eviction, "Enable swappable GEM buffers"); +module_param(enable_eviction, bool, 0600); + +static bool can_swap(void) +{ + return enable_eviction && get_nr_swap_pages() > 0; +} + static unsigned long msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc) { struct msm_drm_private *priv = container_of(shrinker, struct msm_drm_private, shrinker); - return priv->shrinkable_count; + unsigned count = priv->shrinkable_count; + + if (can_swap()) + count += priv->evictable_count; + + return count; } static bool @@ -32,6 +49,17 @@ purge(struct msm_gem_object *msm_obj) return true; } +static bool +evict(struct msm_gem_object *msm_obj) +{ + if (is_unevictable(msm_obj)) + return false; + + msm_gem_evict(&msm_obj->base); + + return true; +} + static unsigned long scan(struct msm_drm_private *priv, unsigned nr_to_scan, struct list_head *list, bool (*shrink)(struct msm_gem_object *msm_obj)) @@ -104,6 +132,16 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) if (freed > 0) trace_msm_gem_purge(freed << PAGE_SHIFT); + if (can_swap() && freed < sc->nr_to_scan) { + int evicted = scan(priv, sc->nr_to_scan - freed, + &priv->inactive_willneed, evict); + + if (evicted > 0) + trace_msm_gem_evict(evicted << PAGE_SHIFT); + + freed += evicted; + } + return (freed > 0) ? freed : SHRINK_STOP; } diff --git a/drivers/gpu/drm/msm/msm_gpu_trace.h b/drivers/gpu/drm/msm/msm_gpu_trace.h index 03e0c25..ca0b08d 100644 --- a/drivers/gpu/drm/msm/msm_gpu_trace.h +++ b/drivers/gpu/drm/msm/msm_gpu_trace.h @@ -128,6 +128,19 @@ TRACE_EVENT(msm_gem_purge, ); +TRACE_EVENT(msm_gem_evict, + TP_PROTO(u32 bytes), + TP_ARGS(bytes), + TP_STRUCT__entry( + __field(u32, bytes) + ), + TP_fast_assign( + __entry->bytes = bytes; + ), + TP_printk("Evicting %u bytes", __entry->bytes) +); + + TRACE_EVENT(msm_gem_purge_vmaps, TP_PROTO(u32 unmapped), TP_ARGS(unmapped), -- 2.7.4