From ced5725b2548b05574e81b1794c24948bd99d891 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 30 May 2019 21:35:00 +0100 Subject: [PATCH] drm/i915: Report all objects with allocated pages to the shrinker Currently, we try to report to the shrinker the precise number of objects (pages) that are available to be reaped at this moment. This requires searching all objects with allocated pages to see if they fulfill the search criteria, and this count is performed quite frequently. (The shrinker tries to free ~128 pages on each invocation, before which we count all the objects; counting takes longer than unbinding the objects!) If we take the pragmatic view that with sufficient desire, all objects are eventually reapable (they become inactive, or no longer used as framebuffer etc), we can simply return the count of pinned pages maintained during get_pages/put_pages rather than walk the lists every time. The downside is that we may (slightly) over-report the number of objects/pages we could shrink and so penalize ourselves by shrinking more than required. This is mitigated by keeping the order in which we shrink objects such that we avoid penalizing active and frequently used objects, and if memory is so tight that we need to free them we would need to anyway. v2: Only expose shrinkable objects to the shrinker; a small reduction in not considering stolen and foreign objects. v3: Restore the tracking from a "backup" copy from before the gem/ split Signed-off-by: Chris Wilson Cc: Joonas Lahtinen Cc: Matthew Auld Reviewed-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20190530203500.26272-2-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/gem/i915_gem_domain.c | 3 +- drivers/gpu/drm/i915/gem/i915_gem_object.c | 33 +++-------- drivers/gpu/drm/i915/gem/i915_gem_pages.c | 20 +++++-- drivers/gpu/drm/i915/gem/i915_gem_shrinker.c | 28 ++-------- drivers/gpu/drm/i915/gem/i915_gem_stolen.c | 2 +- drivers/gpu/drm/i915/i915_debugfs.c | 58 ++------------------ drivers/gpu/drm/i915/i915_drv.h | 7 +-- drivers/gpu/drm/i915/i915_gem.c | 23 ++++---- drivers/gpu/drm/i915/i915_vma.c | 16 ++++-- 9 files changed, 62 insertions(+), 128 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c index 52b73e90c9f42..e5deae62681f6 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c @@ -475,7 +475,8 @@ static void i915_gem_object_bump_inactive_ggtt(struct drm_i915_gem_object *obj) } mutex_unlock(&i915->ggtt.vm.mutex); - if (obj->mm.madv == I915_MADV_WILLNEED) { + if (i915_gem_object_is_shrinkable(obj) && + obj->mm.madv == I915_MADV_WILLNEED) { struct list_head *list; spin_lock(&i915->mm.obj_lock); diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c index 1ec60be067559..b840cf179bbe1 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_object.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c @@ -44,25 +44,6 @@ void i915_gem_object_free(struct drm_i915_gem_object *obj) return kmem_cache_free(global.slab_objects, obj); } -/* some bookkeeping */ -static void i915_gem_info_add_obj(struct drm_i915_private *i915, - u64 size) -{ - spin_lock(&i915->mm.object_stat_lock); - i915->mm.object_count++; - i915->mm.object_memory += size; - spin_unlock(&i915->mm.object_stat_lock); -} - -static void i915_gem_info_remove_obj(struct drm_i915_private *i915, - u64 size) -{ - spin_lock(&i915->mm.object_stat_lock); - i915->mm.object_count--; - i915->mm.object_memory -= size; - spin_unlock(&i915->mm.object_stat_lock); -} - static void frontbuffer_retire(struct i915_active_request *active, struct i915_request *request) @@ -98,8 +79,6 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj, obj->mm.madv = I915_MADV_WILLNEED; INIT_RADIX_TREE(&obj->mm.get_page.radix, GFP_KERNEL | __GFP_NOWARN); mutex_init(&obj->mm.get_page.lock); - - i915_gem_info_add_obj(to_i915(obj->base.dev), obj->base.size); } /** @@ -163,11 +142,14 @@ void i915_gem_close_object(struct drm_gem_object *gem, struct drm_file *file) static bool discard_backing_storage(struct drm_i915_gem_object *obj) { - /* If we are the last user of the backing storage (be it shmemfs + /* + * If we are the last user of the backing storage (be it shmemfs * pages or stolen etc), we know that the pages are going to be * immediately released. In this case, we can then skip copying * back the contents from the GPU. */ + if (!i915_gem_object_is_shrinkable(obj)) + return false; if (obj->mm.madv != I915_MADV_WILLNEED) return false; @@ -208,13 +190,15 @@ static void __i915_gem_free_objects(struct drm_i915_private *i915, GEM_BUG_ON(!list_empty(&obj->vma.list)); GEM_BUG_ON(!RB_EMPTY_ROOT(&obj->vma.tree)); - /* This serializes freeing with the shrinker. Since the free + /* + * This serializes freeing with the shrinker. Since the free * is delayed, first by RCU then by the workqueue, we want the * shrinker to be able to free pages of unreferenced objects, * or else we may oom whilst there are plenty of deferred * freed objects. */ - if (i915_gem_object_has_pages(obj)) { + if (i915_gem_object_has_pages(obj) && + i915_gem_object_is_shrinkable(obj)) { spin_lock(&i915->mm.obj_lock); list_del_init(&obj->mm.link); spin_unlock(&i915->mm.obj_lock); @@ -240,7 +224,6 @@ static void __i915_gem_free_objects(struct drm_i915_private *i915, reservation_object_fini(&obj->__builtin_resv); drm_gem_object_release(&obj->base); - i915_gem_info_remove_obj(i915, obj->base.size); bitmap_free(obj->bit_17); i915_gem_object_free(obj); diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c index e53860147f210..7e64fd6bc19bd 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c @@ -56,9 +56,13 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj, } GEM_BUG_ON(!HAS_PAGE_SIZES(i915, obj->mm.page_sizes.sg)); - spin_lock(&i915->mm.obj_lock); - list_add(&obj->mm.link, &i915->mm.unbound_list); - spin_unlock(&i915->mm.obj_lock); + if (i915_gem_object_is_shrinkable(obj)) { + spin_lock(&i915->mm.obj_lock); + i915->mm.shrink_count++; + i915->mm.shrink_memory += obj->base.size; + list_add(&obj->mm.link, &i915->mm.unbound_list); + spin_unlock(&i915->mm.obj_lock); + } } int ____i915_gem_object_get_pages(struct drm_i915_gem_object *obj) @@ -146,9 +150,13 @@ __i915_gem_object_unset_pages(struct drm_i915_gem_object *obj) if (IS_ERR_OR_NULL(pages)) return pages; - spin_lock(&i915->mm.obj_lock); - list_del(&obj->mm.link); - spin_unlock(&i915->mm.obj_lock); + if (i915_gem_object_is_shrinkable(obj)) { + spin_lock(&i915->mm.obj_lock); + list_del(&obj->mm.link); + i915->mm.shrink_count--; + i915->mm.shrink_memory -= obj->base.size; + spin_unlock(&i915->mm.obj_lock); + } if (obj->mm.mapping) { void *ptr; diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c index 6a93e326abf3a..d71e630c6fb80 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c @@ -309,30 +309,14 @@ i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc) { struct drm_i915_private *i915 = container_of(shrinker, struct drm_i915_private, mm.shrinker); - struct drm_i915_gem_object *obj; - unsigned long num_objects = 0; - unsigned long count = 0; + unsigned long num_objects; + unsigned long count; - spin_lock(&i915->mm.obj_lock); - list_for_each_entry(obj, &i915->mm.unbound_list, mm.link) - if (can_release_pages(obj)) { - count += obj->base.size >> PAGE_SHIFT; - num_objects++; - } + count = READ_ONCE(i915->mm.shrink_memory) >> PAGE_SHIFT; + num_objects = READ_ONCE(i915->mm.shrink_count); - list_for_each_entry(obj, &i915->mm.bound_list, mm.link) - if (!i915_gem_object_is_active(obj) && can_release_pages(obj)) { - count += obj->base.size >> PAGE_SHIFT; - num_objects++; - } - list_for_each_entry(obj, &i915->mm.purge_list, mm.link) - if (!i915_gem_object_is_active(obj) && can_release_pages(obj)) { - count += obj->base.size >> PAGE_SHIFT; - num_objects++; - } - spin_unlock(&i915->mm.obj_lock); - - /* Update our preferred vmscan batch size for the next pass. + /* + * Update our preferred vmscan batch size for the next pass. * Our rough guess for an effective batch size is roughly 2 * available GEM objects worth of pages. That is we don't want * the shrinker to fire, until it is worth the cost of freeing an diff --git a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c index 9080a736663ab..84d4f549eb21c 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c @@ -690,7 +690,7 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_i915_private *dev_priv mutex_unlock(&ggtt->vm.mutex); spin_lock(&dev_priv->mm.obj_lock); - list_move_tail(&obj->mm.link, &dev_priv->mm.bound_list); + GEM_BUG_ON(i915_gem_object_is_shrinkable(obj)); obj->bind_count++; spin_unlock(&dev_priv->mm.obj_lock); diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 74afdeff22457..f212241a27589 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -271,7 +271,7 @@ static int i915_gem_stolen_list_info(struct seq_file *m, void *data) unsigned long total, count, n; int ret; - total = READ_ONCE(dev_priv->mm.object_count); + total = READ_ONCE(dev_priv->mm.shrink_count); objects = kvmalloc_array(total, sizeof(*objects), GFP_KERNEL); if (!objects) return -ENOMEM; @@ -460,9 +460,9 @@ static int i915_gem_object_info(struct seq_file *m, void *data) char buf[80]; int ret; - seq_printf(m, "%u objects, %llu bytes\n", - dev_priv->mm.object_count, - dev_priv->mm.object_memory); + seq_printf(m, "%u shrinkable objects, %llu bytes\n", + dev_priv->mm.shrink_count, + dev_priv->mm.shrink_memory); size = count = 0; mapped_size = mapped_count = 0; @@ -552,55 +552,6 @@ static int i915_gem_object_info(struct seq_file *m, void *data) return 0; } -static int i915_gem_gtt_info(struct seq_file *m, void *data) -{ - struct drm_info_node *node = m->private; - struct drm_i915_private *dev_priv = node_to_i915(node); - struct drm_device *dev = &dev_priv->drm; - struct drm_i915_gem_object **objects; - struct drm_i915_gem_object *obj; - u64 total_obj_size, total_gtt_size; - unsigned long nobject, n; - int count, ret; - - nobject = READ_ONCE(dev_priv->mm.object_count); - objects = kvmalloc_array(nobject, sizeof(*objects), GFP_KERNEL); - if (!objects) - return -ENOMEM; - - ret = mutex_lock_interruptible(&dev->struct_mutex); - if (ret) - return ret; - - count = 0; - spin_lock(&dev_priv->mm.obj_lock); - list_for_each_entry(obj, &dev_priv->mm.bound_list, mm.link) { - objects[count++] = obj; - if (count == nobject) - break; - } - spin_unlock(&dev_priv->mm.obj_lock); - - total_obj_size = total_gtt_size = 0; - for (n = 0; n < count; n++) { - obj = objects[n]; - - seq_puts(m, " "); - describe_obj(m, obj); - seq_putc(m, '\n'); - total_obj_size += obj->base.size; - total_gtt_size += i915_gem_obj_total_ggtt_size(obj); - } - - mutex_unlock(&dev->struct_mutex); - - seq_printf(m, "Total %d objects, %llu bytes, %llu GTT size\n", - count, total_obj_size, total_gtt_size); - kvfree(objects); - - return 0; -} - static int i915_gem_batch_pool_info(struct seq_file *m, void *data) { struct drm_i915_private *dev_priv = node_to_i915(m->private); @@ -4582,7 +4533,6 @@ static const struct file_operations i915_fifo_underrun_reset_ops = { static const struct drm_info_list i915_debugfs_list[] = { {"i915_capabilities", i915_capabilities, 0}, {"i915_gem_objects", i915_gem_object_info, 0}, - {"i915_gem_gtt", i915_gem_gtt_info, 0}, {"i915_gem_stolen", i915_gem_stolen_list_info }, {"i915_gem_fence_regs", i915_gem_fence_regs_info, 0}, {"i915_gem_interrupt", i915_interrupt_info, 0}, diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index dc21955891c78..76f2bf90ed86e 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -926,10 +926,9 @@ struct i915_gem_mm { /** Bit 6 swizzling required for Y tiling */ u32 bit_6_swizzle_y; - /* accounting, useful for userland debugging */ - spinlock_t object_stat_lock; - u64 object_memory; - u32 object_count; + /* shrinker accounting, also useful for userland debugging */ + u64 shrink_memory; + u32 shrink_count; }; #define I915_IDLE_ENGINES_TIMEOUT (200) /* in ms */ diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 1362a8803d2a2..4739a6307c32e 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1137,15 +1137,17 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data, if (i915_gem_object_has_pages(obj)) { struct list_head *list; - spin_lock(&i915->mm.obj_lock); - if (obj->mm.madv != I915_MADV_WILLNEED) - list = &i915->mm.purge_list; - else if (obj->bind_count) - list = &i915->mm.bound_list; - else - list = &i915->mm.unbound_list; - list_move_tail(&obj->mm.link, list); - spin_unlock(&i915->mm.obj_lock); + if (i915_gem_object_is_shrinkable(obj)) { + spin_lock(&i915->mm.obj_lock); + if (obj->mm.madv != I915_MADV_WILLNEED) + list = &i915->mm.purge_list; + else if (obj->bind_count) + list = &i915->mm.bound_list; + else + list = &i915->mm.unbound_list; + list_move_tail(&obj->mm.link, list); + spin_unlock(&i915->mm.obj_lock); + } } /* if the object is no longer attached, discard its backing storage */ @@ -1758,7 +1760,6 @@ i915_gem_load_init_fences(struct drm_i915_private *dev_priv) static void i915_gem_init__mm(struct drm_i915_private *i915) { - spin_lock_init(&i915->mm.object_stat_lock); spin_lock_init(&i915->mm.obj_lock); spin_lock_init(&i915->mm.free_lock); @@ -1808,7 +1809,7 @@ void i915_gem_cleanup_early(struct drm_i915_private *dev_priv) i915_gem_drain_freed_objects(dev_priv); GEM_BUG_ON(!llist_empty(&dev_priv->mm.free_list)); GEM_BUG_ON(atomic_read(&dev_priv->mm.free_count)); - WARN_ON(dev_priv->mm.object_count); + WARN_ON(dev_priv->mm.shrink_count); cleanup_srcu_struct(&dev_priv->gpu_error.reset_backoff_srcu); diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index f640caec4bae6..b7fb7d216f77d 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -110,7 +110,8 @@ static void __i915_vma_retire(struct i915_active *ref) * so that we don't steal from recently used but inactive objects * (unless we are forced to ofc!) */ - obj_bump_mru(obj); + if (i915_gem_object_is_shrinkable(obj)) + obj_bump_mru(obj); i915_gem_object_put(obj); /* and drop the active reference */ } @@ -677,11 +678,14 @@ i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags) struct drm_i915_gem_object *obj = vma->obj; spin_lock(&dev_priv->mm.obj_lock); - list_move_tail(&obj->mm.link, &dev_priv->mm.bound_list); - obj->bind_count++; - spin_unlock(&dev_priv->mm.obj_lock); + if (i915_gem_object_is_shrinkable(obj)) + list_move_tail(&obj->mm.link, &dev_priv->mm.bound_list); + + obj->bind_count++; assert_bind_count(obj); + + spin_unlock(&dev_priv->mm.obj_lock); } return 0; @@ -717,9 +721,13 @@ i915_vma_remove(struct i915_vma *vma) struct drm_i915_gem_object *obj = vma->obj; spin_lock(&i915->mm.obj_lock); + + GEM_BUG_ON(obj->bind_count == 0); if (--obj->bind_count == 0 && + i915_gem_object_is_shrinkable(obj) && obj->mm.madv == I915_MADV_WILLNEED) list_move_tail(&obj->mm.link, &i915->mm.unbound_list); + spin_unlock(&i915->mm.obj_lock); /* -- 2.39.5