Re: [Freedreno] [PATCH 04/14] drm/msm: Add priv->mm_lock to protect active/inactive lists

On Sun, Oct 04, 2020 at 12:21:36PM -0700, Rob Clark wrote:

From: Rob Clark robdclark@chromium.org

Rather than relying on the big dev->struct_mutex hammer, introduce a more specific lock for protecting the bo lists.

Most excellent.

Reviewed-by: Jordan Crouse jcrouse@codeaurora.org

Signed-off-by: Rob Clark robdclark@chromium.org

drivers/gpu/drm/msm/msm_debugfs.c | 7 +++++++ drivers/gpu/drm/msm/msm_drv.c | 1 + drivers/gpu/drm/msm/msm_drv.h | 13 +++++++++++- drivers/gpu/drm/msm/msm_gem.c | 28 +++++++++++++++----------- drivers/gpu/drm/msm/msm_gem_shrinker.c | 12 +++++++++++ drivers/gpu/drm/msm/msm_gpu.h | 5 ++++- 6 files changed, 52 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_debugfs.c b/drivers/gpu/drm/msm/msm_debugfs.c index ee2e270f464c..64afbed89821 100644 --- a/drivers/gpu/drm/msm/msm_debugfs.c +++ b/drivers/gpu/drm/msm/msm_debugfs.c @@ -112,6 +112,11 @@ static int msm_gem_show(struct drm_device *dev, struct seq_file *m) { struct msm_drm_private *priv = dev->dev_private; struct msm_gpu *gpu = priv->gpu;

• int ret;

• ret = mutex_lock_interruptible(&priv->mm_lock);

• if (ret)

• return ret;
  
  

  if (gpu) { seq_printf(m, "Active Objects (%s):\n", gpu->name);

@@ -121,6 +126,8 @@ static int msm_gem_show(struct drm_device *dev, struct seq_file *m) seq_printf(m, "Inactive Objects:\n"); msm_gem_describe_objects(&priv->inactive_list, m);

• mutex_unlock(&priv->mm_lock);
• return 0;

}

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c index 49685571dc0e..dc6efc089285 100644 --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -441,6 +441,7 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv) init_llist_head(&priv->free_list);

INIT_LIST_HEAD(&priv->inactive_list);

• mutex_init(&priv->mm_lock);

  drm_mode_config_init(ddev);

diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h index b9dd8f8f4887..50978e5db376 100644 --- a/drivers/gpu/drm/msm/msm_drv.h +++ b/drivers/gpu/drm/msm/msm_drv.h @@ -174,8 +174,19 @@ struct msm_drm_private { struct msm_rd_state *hangrd; /* debugfs to dump hanging submits */ struct msm_perf_state *perf;

• /* list of GEM objects: */

• /*

• * List of inactive GEM objects.  Every bo is either in the inactive_list
  

• * or gpu->active_list (for the gpu it is active on[1])
  

• *
  

• * These lists are protected by mm_lock.  If struct_mutex is involved, it
  

• * should be aquired prior to mm_lock.  One should *not* hold mm_lock in
  

• * get_pages()/vmap()/etc paths, as they can trigger the shrinker.
  

• *
  

• * [1] if someone ever added support for the old 2d cores, there could be
  

• *     more than one gpu object
  

• */
  

  struct list_head inactive_list;

• struct mutex mm_lock;

  /* worker for delayed free of objects: */ struct work_struct free_work;

diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c index a870b3ad129d..b04ed8b52f9d 100644 --- a/drivers/gpu/drm/msm/msm_gem.c +++ b/drivers/gpu/drm/msm/msm_gem.c @@ -746,13 +746,17 @@ int msm_gem_sync_object(struct drm_gem_object *obj, void msm_gem_active_get(struct drm_gem_object *obj, struct msm_gpu *gpu) { struct msm_gem_object *msm_obj = to_msm_bo(obj);

• WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));

• struct msm_drm_private *priv = obj->dev->dev_private;

• might_sleep(); WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED);

  if (!atomic_fetch_inc(&msm_obj->active_count)) {

• mutex_lock(&priv->mm_lock);
  

  msm_obj->gpu = gpu; list_del_init(&msm_obj->mm_list); list_add_tail(&msm_obj->mm_list, &gpu->active_list);

• mutex_unlock(&priv->mm_lock);
  

  }

}

@@ -761,12 +765,14 @@ void msm_gem_active_put(struct drm_gem_object *obj) struct msm_gem_object *msm_obj = to_msm_bo(obj); struct msm_drm_private *priv = obj->dev->dev_private;

• WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));

• might_sleep();

  if (!atomic_dec_return(&msm_obj->active_count)) {

• mutex_lock(&priv->mm_lock);
  

  msm_obj->gpu = NULL; list_del_init(&msm_obj->mm_list); list_add_tail(&msm_obj->mm_list, &priv->inactive_list);

• mutex_unlock(&priv->mm_lock);
  

  }

}

@@ -921,13 +927,16 @@ static void free_object(struct msm_gem_object *msm_obj) { struct drm_gem_object *obj = &msm_obj->base; struct drm_device *dev = obj->dev;

• struct msm_drm_private *priv = dev->dev_private;

  WARN_ON(!mutex_is_locked(&dev->struct_mutex));

  /* object should not be on active list: */ WARN_ON(is_active(msm_obj));

• mutex_lock(&priv->mm_lock); list_del(&msm_obj->mm_list);

• mutex_unlock(&priv->mm_lock);

  mutex_lock(&msm_obj->lock);

@@ -1103,14 +1112,9 @@ static struct drm_gem_object *_msm_gem_new(struct drm_device *dev, mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER); }

• if (struct_mutex_locked) {

• WARN_ON(!mutex_is_locked(&dev->struct_mutex));
  

• list_add_tail(&msm_obj->mm_list, &priv->inactive_list);
  

• } else {

• mutex_lock(&dev->struct_mutex);
  

• list_add_tail(&msm_obj->mm_list, &priv->inactive_list);
  

• mutex_unlock(&dev->struct_mutex);
  

• }

• mutex_lock(&priv->mm_lock);

• list_add_tail(&msm_obj->mm_list, &priv->inactive_list);

• mutex_unlock(&priv->mm_lock);

  return obj;

@@ -1178,9 +1182,9 @@ struct drm_gem_object *msm_gem_import(struct drm_device *dev,

mutex_unlock(&msm_obj->lock);

• mutex_lock(&dev->struct_mutex);

• mutex_lock(&priv->mm_lock); list_add_tail(&msm_obj->mm_list, &priv->inactive_list);

• mutex_unlock(&dev->struct_mutex);

• mutex_unlock(&priv->mm_lock);

  return obj;

diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c index 482576d7a39a..c41b84a3a484 100644 --- a/drivers/gpu/drm/msm/msm_gem_shrinker.c +++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c @@ -51,11 +51,15 @@ msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc) if (!msm_gem_shrinker_lock(dev, &unlock)) return 0;

• mutex_lock(&priv->mm_lock);

• list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) { if (is_purgeable(msm_obj)) count += msm_obj->base.size >> PAGE_SHIFT; }

• mutex_unlock(&priv->mm_lock);

• if (unlock) mutex_unlock(&dev->struct_mutex);

@@ -75,6 +79,8 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) if (!msm_gem_shrinker_lock(dev, &unlock)) return SHRINK_STOP;

• mutex_lock(&priv->mm_lock);
• list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) { if (freed >= sc->nr_to_scan) break;

@@ -84,6 +90,8 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) } }

• mutex_unlock(&priv->mm_lock);
• if (unlock) mutex_unlock(&dev->struct_mutex);

@@ -106,6 +114,8 @@ msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr) if (!msm_gem_shrinker_lock(dev, &unlock)) return NOTIFY_DONE;

• mutex_lock(&priv->mm_lock);
• list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) { if (is_vunmapable(msm_obj)) { msm_gem_vunmap(&msm_obj->base, OBJ_LOCK_SHRINKER);

@@ -118,6 +128,8 @@ msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr) } }

• mutex_unlock(&priv->mm_lock);
• if (unlock) mutex_unlock(&dev->struct_mutex);

diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h index 6c9e1fdc1a76..1806e87600c0 100644 --- a/drivers/gpu/drm/msm/msm_gpu.h +++ b/drivers/gpu/drm/msm/msm_gpu.h @@ -94,7 +94,10 @@ struct msm_gpu { struct msm_ringbuffer *rb[MSM_GPU_MAX_RINGS]; int nr_rings;

• /* list of GEM active objects: */

• /*

• * List of GEM active objects on this gpu.  Protected by
  

• * msm_drm_private::mm_lock
  

• */
  

  struct list_head active_list;

  /* does gpu need hw_init? */

-- 2.26.2

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