Re: [PATCH v10 08/11] drm/shmem-helper: Add memory shrinker
On 2/17/23 16:19, Thomas Zimmermann wrote: >> +/** >> + * drm_gem_shmem_swap_in() - Moves shmem GEM back to memory and enables >> + * hardware access to the memory. > > Do we have a better name than _swap_in()? I suggest > drm_gem_shmem_unevict(), which suggest that it's the inverse to _evict(). The canonical naming scheme used by TTM and other DRM drivers is _swapin(), without the underscore. I'll use that variant in v11 for the naming consistency with the rest of DRM code. -- Best regards, Dmitry
Re: [PATCH v10 08/11] drm/shmem-helper: Add memory shrinker
Hi
Am 08.01.23 um 22:04 schrieb Dmitry Osipenko:
Introduce common drm-shmem shrinker for DRM drivers.
To start using drm-shmem shrinker drivers should do the following:
1. Implement evict() callback of GEM object where driver should check
whether object is purgeable or evictable using drm-shmem helpers and
perform the shrinking action
2. Initialize drm-shmem internals using drmm_gem_shmem_init(drm_device),
which will register drm-shmem shrinker
3. Implement madvise IOCTL that will use drm_gem_shmem_madvise()
I left commenets beloew, but it's complicated code and a fairly large
change. It there any chance of splitting this up in a meaningful way?
Signed-off-by: Daniel Almeida
Signed-off-by: Dmitry Osipenko
---
drivers/gpu/drm/drm_gem_shmem_helper.c| 460 --
.../gpu/drm/panfrost/panfrost_gem_shrinker.c | 9 +-
include/drm/drm_device.h | 10 +-
include/drm/drm_gem_shmem_helper.h| 61 ++-
4 files changed, 490 insertions(+), 50 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c
b/drivers/gpu/drm/drm_gem_shmem_helper.c
index a1f2f2158c50..3ab5ec325ddb 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -20,6 +20,7 @@
#include
#include
#include
+#include
#include
#include
@@ -128,6 +129,57 @@ struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_create);
+static void drm_gem_shmem_resv_assert_held(struct drm_gem_shmem_object *shmem)
+{
+ /*
+* Destroying the object is a special case.. drm_gem_shmem_free()
+* calls many things that WARN_ON if the obj lock is not held. But
+* acquiring the obj lock in drm_gem_shmem_free() can cause a locking
+* order inversion between reservation_ww_class_mutex and fs_reclaim.
+*
+* This deadlock is not actually possible, because no one should
+* be already holding the lock when msm_gem_free_object() is called.
+* Unfortunately lockdep is not aware of this detail. So when the
+* refcount drops to zero, we pretend it is already locked.
+*/
+ if (kref_read(&shmem->base.refcount))
+ dma_resv_assert_held(shmem->base.resv);
+}
+
+static bool drm_gem_shmem_is_evictable(struct drm_gem_shmem_object *shmem)
+{
+ dma_resv_assert_held(shmem->base.resv);
+
+ return (shmem->madv >= 0) && shmem->base.funcs->evict &&
+ shmem->pages_use_count && !shmem->pages_pin_count &&
+ !shmem->base.dma_buf && !shmem->base.import_attach &&
+ shmem->sgt && !shmem->evicted;
+}
+
+static void
+drm_gem_shmem_update_pages_state(struct drm_gem_shmem_object *shmem)
+{
+ struct drm_gem_object *obj = &shmem->base;
+ struct drm_gem_shmem *shmem_mm = obj->dev->shmem_mm;
+ struct drm_gem_shmem_shrinker *gem_shrinker = &shmem_mm->shrinker;
+
+ drm_gem_shmem_resv_assert_held(shmem);
+
+ if (!gem_shrinker || obj->import_attach)
+ return;
+
+ if (shmem->madv < 0)
+ drm_gem_lru_remove(&shmem->base);
+ else if (drm_gem_shmem_is_evictable(shmem) ||
drm_gem_shmem_is_purgeable(shmem))
+ drm_gem_lru_move_tail(&gem_shrinker->lru_evictable,
&shmem->base);
+ else if (shmem->evicted)
+ drm_gem_lru_move_tail(&gem_shrinker->lru_evicted, &shmem->base);
+ else if (!shmem->pages)
+ drm_gem_lru_remove(&shmem->base);
+ else
+ drm_gem_lru_move_tail(&gem_shrinker->lru_pinned, &shmem->base);
+}
+
/**
* drm_gem_shmem_free - Free resources associated with a shmem GEM object
* @shmem: shmem GEM object to free
@@ -142,7 +194,8 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
if (obj->import_attach) {
drm_prime_gem_destroy(obj, shmem->sgt);
} else {
- dma_resv_lock(shmem->base.resv, NULL);
+ /* take out shmem GEM object from the memory shrinker */
+ drm_gem_shmem_madvise(shmem, -1);
drm_WARN_ON(obj->dev, shmem->vmap_use_count);
@@ -152,12 +205,10 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
sg_free_table(shmem->sgt);
kfree(shmem->sgt);
}
- if (shmem->pages)
+ if (shmem->pages_use_count)
drm_gem_shmem_put_pages(shmem);
drm_WARN_ON(obj->dev, shmem->pages_use_count);
-
- dma_resv_unlock(shmem->base.resv);
}
drm_gem_object_release(obj);
@@ -165,19 +216,31 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object
*shmem)
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_free);
-static int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
+static int
+drm_gem_shmem_acquire_pages(struct drm_gem_shmem_object *shmem)
{
struct drm_
[PATCH v10 08/11] drm/shmem-helper: Add memory shrinker
Introduce common drm-shmem shrinker for DRM drivers.
To start using drm-shmem shrinker drivers should do the following:
1. Implement evict() callback of GEM object where driver should check
whether object is purgeable or evictable using drm-shmem helpers and
perform the shrinking action
2. Initialize drm-shmem internals using drmm_gem_shmem_init(drm_device),
which will register drm-shmem shrinker
3. Implement madvise IOCTL that will use drm_gem_shmem_madvise()
Signed-off-by: Daniel Almeida
Signed-off-by: Dmitry Osipenko
---
drivers/gpu/drm/drm_gem_shmem_helper.c| 460 --
.../gpu/drm/panfrost/panfrost_gem_shrinker.c | 9 +-
include/drm/drm_device.h | 10 +-
include/drm/drm_gem_shmem_helper.h| 61 ++-
4 files changed, 490 insertions(+), 50 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c
b/drivers/gpu/drm/drm_gem_shmem_helper.c
index a1f2f2158c50..3ab5ec325ddb 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -20,6 +20,7 @@
#include
#include
#include
+#include
#include
#include
@@ -128,6 +129,57 @@ struct drm_gem_shmem_object *drm_gem_shmem_create(struct
drm_device *dev, size_t
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_create);
+static void drm_gem_shmem_resv_assert_held(struct drm_gem_shmem_object *shmem)
+{
+ /*
+* Destroying the object is a special case.. drm_gem_shmem_free()
+* calls many things that WARN_ON if the obj lock is not held. But
+* acquiring the obj lock in drm_gem_shmem_free() can cause a locking
+* order inversion between reservation_ww_class_mutex and fs_reclaim.
+*
+* This deadlock is not actually possible, because no one should
+* be already holding the lock when msm_gem_free_object() is called.
+* Unfortunately lockdep is not aware of this detail. So when the
+* refcount drops to zero, we pretend it is already locked.
+*/
+ if (kref_read(&shmem->base.refcount))
+ dma_resv_assert_held(shmem->base.resv);
+}
+
+static bool drm_gem_shmem_is_evictable(struct drm_gem_shmem_object *shmem)
+{
+ dma_resv_assert_held(shmem->base.resv);
+
+ return (shmem->madv >= 0) && shmem->base.funcs->evict &&
+ shmem->pages_use_count && !shmem->pages_pin_count &&
+ !shmem->base.dma_buf && !shmem->base.import_attach &&
+ shmem->sgt && !shmem->evicted;
+}
+
+static void
+drm_gem_shmem_update_pages_state(struct drm_gem_shmem_object *shmem)
+{
+ struct drm_gem_object *obj = &shmem->base;
+ struct drm_gem_shmem *shmem_mm = obj->dev->shmem_mm;
+ struct drm_gem_shmem_shrinker *gem_shrinker = &shmem_mm->shrinker;
+
+ drm_gem_shmem_resv_assert_held(shmem);
+
+ if (!gem_shrinker || obj->import_attach)
+ return;
+
+ if (shmem->madv < 0)
+ drm_gem_lru_remove(&shmem->base);
+ else if (drm_gem_shmem_is_evictable(shmem) ||
drm_gem_shmem_is_purgeable(shmem))
+ drm_gem_lru_move_tail(&gem_shrinker->lru_evictable,
&shmem->base);
+ else if (shmem->evicted)
+ drm_gem_lru_move_tail(&gem_shrinker->lru_evicted, &shmem->base);
+ else if (!shmem->pages)
+ drm_gem_lru_remove(&shmem->base);
+ else
+ drm_gem_lru_move_tail(&gem_shrinker->lru_pinned, &shmem->base);
+}
+
/**
* drm_gem_shmem_free - Free resources associated with a shmem GEM object
* @shmem: shmem GEM object to free
@@ -142,7 +194,8 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
if (obj->import_attach) {
drm_prime_gem_destroy(obj, shmem->sgt);
} else {
- dma_resv_lock(shmem->base.resv, NULL);
+ /* take out shmem GEM object from the memory shrinker */
+ drm_gem_shmem_madvise(shmem, -1);
drm_WARN_ON(obj->dev, shmem->vmap_use_count);
@@ -152,12 +205,10 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object
*shmem)
sg_free_table(shmem->sgt);
kfree(shmem->sgt);
}
- if (shmem->pages)
+ if (shmem->pages_use_count)
drm_gem_shmem_put_pages(shmem);
drm_WARN_ON(obj->dev, shmem->pages_use_count);
-
- dma_resv_unlock(shmem->base.resv);
}
drm_gem_object_release(obj);
@@ -165,19 +216,31 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object
*shmem)
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_free);
-static int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
+static int
+drm_gem_shmem_acquire_pages(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
struct page **pages;
- if (shmem->pages_use_count++ > 0)
+ dma_resv_assert_held(shmem->base.resv);
+
+ if (shmem->madv < 0) {
+
