[PATCH v6 21/45] drm/msm: dynamically allocate the drm-msm_gem shrinker

Qi Zheng
2023-09-11T21:40:28Z

In preparation for implementing lockless slab shrink, use new APIs to
dynamically allocate the drm-msm_gem shrinker, so that it can be freed
asynchronously via RCU. Then it doesn't need to wait for RCU read-side
critical section when releasing the struct msm_drm_private.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
CC: Rob Clark <robdclark@gmail.com>
CC: Abhinav Kumar <quic_abhinavk@quicinc.com>
CC: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
CC: Sean Paul <sean@poorly.run>
CC: Marijn Suijten <marijn.suijten@somainline.org>
CC: David Airlie <airlied@gmail.com>
CC: linux-arm-msm@vger.kernel.org
CC: dri-devel@lists.freedesktop.org
---
drivers/gpu/drm/msm/msm_drv.c | 4 +++-
drivers/gpu/drm/msm/msm_drv.h | 4 ++--
drivers/gpu/drm/msm/msm_gem_shrinker.c | 33 ++++++++++++++++----------
3 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 4bd028fa7500..7f20249d6071 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -462,7 +462,9 @@ static int msm_drm_init(struct device *dev, const struct drm_driver *drv)
if (ret)
goto err_msm_uninit;

- msm_gem_shrinker_init(ddev);
+ ret = msm_gem_shrinker_init(ddev);
+ if (ret)
+ goto err_msm_uninit;

if (priv->kms_init) {
ret = priv->kms_init(ddev);
diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index 02fd6c7d0bb7..e2fc56f161b5 100644
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -221,7 +221,7 @@ struct msm_drm_private {
} vram;

struct notifier_block vmap_notifier;
- struct shrinker shrinker;
+ struct shrinker *shrinker;

struct drm_atomic_state *pm_state;

@@ -283,7 +283,7 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
unsigned long msm_gem_shrinker_shrink(struct drm_device *dev, unsigned long nr_to_scan);
#endif

-void msm_gem_shrinker_init(struct drm_device *dev);
+int msm_gem_shrinker_init(struct drm_device *dev);
void msm_gem_shrinker_cleanup(struct drm_device *dev);

struct sg_table *msm_gem_prime_get_sg_table(struct drm_gem_object *obj);
diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c
index f38296ad8743..5a7d48c02c4b 100644
--- a/drivers/gpu/drm/msm/msm_gem_shrinker.c
+++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
@@ -34,8 +34,7 @@ static bool can_block(struct shrink_control *sc)
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);
+ struct msm_drm_private *priv = shrinker->private_data;
unsigned count = priv->lru.dontneed.count;

if (can_swap())
@@ -100,8 +99,7 @@ active_evict(struct drm_gem_object *obj)
static unsigned long
msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
{
- struct msm_drm_private *priv =
- container_of(shrinker, struct msm_drm_private, shrinker);
+ struct msm_drm_private *priv = shrinker->private_data;
struct {
struct drm_gem_lru *lru;
bool (*shrink)(struct drm_gem_object *obj);
@@ -148,10 +146,11 @@ msm_gem_shrinker_shrink(struct drm_device *dev, unsigned long nr_to_scan)
struct shrink_control sc = {
.nr_to_scan = nr_to_scan,
};
- int ret;
+ unsigned long ret = SHRINK_STOP;

fs_reclaim_acquire(GFP_KERNEL);
- ret = msm_gem_shrinker_scan(&priv->shrinker, &sc);
+ if (priv->shrinker)
+ ret = msm_gem_shrinker_scan(priv->shrinker, &sc);
fs_reclaim_release(GFP_KERNEL);

return ret;
@@ -210,16 +209,24 @@ msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
*
* This function registers and sets up the msm shrinker.
*/
-void msm_gem_shrinker_init(struct drm_device *dev)
+int msm_gem_shrinker_init(struct drm_device *dev)
{
struct msm_drm_private *priv = dev->dev_private;
- priv->shrinker.count_objects = msm_gem_shrinker_count;
- priv->shrinker.scan_objects = msm_gem_shrinker_scan;
- priv->shrinker.seeks = DEFAULT_SEEKS;
- WARN_ON(register_shrinker(&priv->shrinker, "drm-msm_gem"));
+
+ priv->shrinker = shrinker_alloc(0, "drm-msm_gem");
+ if (!priv->shrinker)
+ return -ENOMEM;
+
+ priv->shrinker->count_objects = msm_gem_shrinker_count;
+ priv->shrinker->scan_objects = msm_gem_shrinker_scan;
+ priv->shrinker->private_data = priv;
+
+ shrinker_register(priv->shrinker);

priv->vmap_notifier.notifier_call = msm_gem_shrinker_vmap;
WARN_ON(register_vmap_purge_notifier(&priv->vmap_notifier));
+
+ return 0;
}

/**
@@ -232,8 +239,8 @@ void msm_gem_shrinker_cleanup(struct drm_device *dev)
{
struct msm_drm_private *priv = dev->dev_private;

- if (priv->shrinker.nr_deferred) {
+ if (priv->shrinker) {
WARN_ON(unregister_vmap_purge_notifier(&priv->vmap_notifier));
- unregister_shrinker(&priv->shrinker);
+ shrinker_free(priv->shrinker);
}
}
--
2.30.2