From: Rob Clark <robdcl...@chromium.org>
If the callback is going to have to attempt to grab more locks, it is
useful to have an ww_acquire_ctx to avoid locking order problems.
Why not use the drm_exec helper instead? Mainly because (a) where
ww_acquire_init() is called is awkward, and (b) we don't really
need to retry after backoff, we can just move on to the next object.
Signed-off-by: Rob Clark <robdcl...@chromium.org>
---
drivers/gpu/drm/drm_gem.c | 14 +++++++++++---
drivers/gpu/drm/msm/msm_gem_shrinker.c | 24 +++++++++++++-----------
include/drm/drm_gem.h | 10 ++++++----
3 files changed, 30 insertions(+), 18 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index ee811764c3df..9e3db9a864f8 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1460,12 +1460,14 @@ EXPORT_SYMBOL(drm_gem_lru_move_tail);
* @nr_to_scan: The number of pages to try to reclaim
* @remaining: The number of pages left to reclaim, should be initialized by
caller
* @shrink: Callback to try to shrink/reclaim the object.
+ * @ticket: Optional ww_acquire_ctx context to use for locking
*/
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))
+ bool (*shrink)(struct drm_gem_object *obj, struct
ww_acquire_ctx *ticket),
+ struct ww_acquire_ctx *ticket)
{
struct drm_gem_lru still_in_lru;
struct drm_gem_object *obj;
@@ -1498,17 +1500,20 @@ drm_gem_lru_scan(struct drm_gem_lru *lru,
*/
mutex_unlock(lru->lock);
+ if (ticket)
+ ww_acquire_init(ticket, &reservation_ww_class);
+
/*
* Note that this still needs to be trylock, since we can
* hit shrinker in response to trying to get backing pages
* for this obj (ie. while it's lock is already held)
*/
- if (!dma_resv_trylock(obj->resv)) {
+ if (!ww_mutex_trylock(&obj->resv->lock, ticket)) {
*remaining += obj->size >> PAGE_SHIFT;
goto tail;
}
- if (shrink(obj)) {
+ if (shrink(obj, ticket)) {
freed += obj->size >> PAGE_SHIFT;
/*
@@ -1522,6 +1527,9 @@ drm_gem_lru_scan(struct drm_gem_lru *lru,
dma_resv_unlock(obj->resv);
+ if (ticket)
+ ww_acquire_fini(ticket);
+
tail:
drm_gem_object_put(obj);
mutex_lock(lru->lock);
diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c
b/drivers/gpu/drm/msm/msm_gem_shrinker.c
index 07ca4ddfe4e3..de185fc34084 100644
--- a/drivers/gpu/drm/msm/msm_gem_shrinker.c
+++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
@@ -44,7 +44,7 @@ msm_gem_shrinker_count(struct shrinker *shrinker, struct
shrink_control *sc)
}
static bool
-purge(struct drm_gem_object *obj)
+purge(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
{
if (!is_purgeable(to_msm_bo(obj)))
return false;
@@ -58,7 +58,7 @@ purge(struct drm_gem_object *obj)
}
static bool
-evict(struct drm_gem_object *obj)
+evict(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
{
if (is_unevictable(to_msm_bo(obj)))
return false;
@@ -79,21 +79,21 @@ wait_for_idle(struct drm_gem_object *obj)
}
static bool
-active_purge(struct drm_gem_object *obj)
+active_purge(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
{
if (!wait_for_idle(obj))
return false;
- return purge(obj);
+ return purge(obj, ticket);
}
static bool
-active_evict(struct drm_gem_object *obj)
+active_evict(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
{
if (!wait_for_idle(obj))
return false;
- return evict(obj);
+ return evict(obj, ticket);
}
static unsigned long
@@ -102,7 +102,7 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct
shrink_control *sc)
struct msm_drm_private *priv = shrinker->private_data;
struct {
struct drm_gem_lru *lru;
- bool (*shrink)(struct drm_gem_object *obj);
+ bool (*shrink)(struct drm_gem_object *obj, struct
ww_acquire_ctx *ticket);
bool cond;
unsigned long freed;
unsigned long remaining;
@@ -122,8 +122,9 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct
shrink_control *sc)
continue;
stages[i].freed =
drm_gem_lru_scan(stages[i].lru, nr,
- &stages[i].remaining,
- stages[i].shrink);
+ &stages[i].remaining,
+ stages[i].shrink,
+ NULL);
nr -= stages[i].freed;
freed += stages[i].freed;
remaining += stages[i].remaining;
@@ -164,7 +165,7 @@ msm_gem_shrinker_shrink(struct drm_device *dev, unsigned
long nr_to_scan)
static const int vmap_shrink_limit = 15;
static bool
-vmap_shrink(struct drm_gem_object *obj)
+vmap_shrink(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
{
if (!is_vunmapable(to_msm_bo(obj)))
return false;
@@ -192,7 +193,8 @@ msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned
long event, void *ptr)
unmapped += drm_gem_lru_scan(lrus[idx],
vmap_shrink_limit - unmapped,
&remaining,
- vmap_shrink);
+ vmap_shrink,
+ NULL);
}
*(unsigned long *)ptr += unmapped;
diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index fdae947682cd..0e2c476df731 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -555,10 +555,12 @@ 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_locked(struct drm_gem_lru *lru, 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 int nr_to_scan,
- unsigned long *remaining,
- bool (*shrink)(struct drm_gem_object *obj));
+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, struct
ww_acquire_ctx *ticket),
+ struct ww_acquire_ctx *ticket);
int drm_gem_evict(struct drm_gem_object *obj);
--
2.49.0
