Commit 17b704f1 authored by Rob Clark's avatar Rob Clark
Browse files

drm/msm/gem: Avoid obj lock in job_run() 



Now that everything that controls which LRU an obj lives in *except* the
backing pages is protected by the LRU lock, add a special path to unpin
in the job_run() path, where we are assured that we already have backing
pages and will not be racing against eviction (because the GEM object's
dma_resv contains the fence that will be signaled when the submit/job
completes).

Signed-off-by: default avatarRob Clark <robdclark@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/527845/
Link: https://lore.kernel.org/r/20230320144356.803762-10-robdclark@gmail.com
parent 6c7c8fb8

drivers/gpu/drm/msm/msm_gem.c

+37 −7
Original line number Diff line number Diff line
@@ -61,18 +61,14 @@ static void sync_for_cpu(struct msm_gem_object *msm_obj) 
	dma_unmap_sgtable(dev, msm_obj->sgt, DMA_BIDIRECTIONAL, 0);

}



static void update_lru_locked(struct drm_gem_object *obj)

static void update_lru_active(struct drm_gem_object *obj)

{

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

	struct msm_gem_object *msm_obj = to_msm_bo(obj);



	msm_gem_assert_locked(&msm_obj->base);



	if (!msm_obj->pages) {

		GEM_WARN_ON(msm_obj->pin_count);

	GEM_WARN_ON(!msm_obj->pages);



		drm_gem_lru_move_tail_locked(&priv->lru.unbacked, obj);

	} else if (msm_obj->pin_count) {

	if (msm_obj->pin_count) {

		drm_gem_lru_move_tail_locked(&priv->lru.pinned, obj);

	} else if (msm_obj->madv == MSM_MADV_WILLNEED) {

		drm_gem_lru_move_tail_locked(&priv->lru.willneed, obj);
@@ -83,6 +79,22 @@ static void update_lru_locked(struct drm_gem_object *obj) 
	}

}



static void update_lru_locked(struct drm_gem_object *obj)

{

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

	struct msm_gem_object *msm_obj = to_msm_bo(obj);



	msm_gem_assert_locked(&msm_obj->base);



	if (!msm_obj->pages) {

		GEM_WARN_ON(msm_obj->pin_count);



		drm_gem_lru_move_tail_locked(&priv->lru.unbacked, obj);

	} else {

		update_lru_active(obj);

	}

}



static void update_lru(struct drm_gem_object *obj)

{

	struct msm_drm_private *priv = obj->dev->dev_private;
@@ -489,6 +501,24 @@ void msm_gem_unpin_locked(struct drm_gem_object *obj) 
	mutex_unlock(&priv->lru.lock);

}



/* Special unpin path for use in fence-signaling path, avoiding the need

 * to hold the obj lock by only depending on things that a protected by

 * the LRU lock.  In particular we know that that we already have backing

 * and and that the object's dma_resv has the fence for the current

 * submit/job which will prevent us racing against page eviction.

 */

void msm_gem_unpin_active(struct drm_gem_object *obj)

{

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

	struct msm_gem_object *msm_obj = to_msm_bo(obj);



	mutex_lock(&priv->lru.lock);

	msm_obj->pin_count--;

	GEM_WARN_ON(msm_obj->pin_count < 0);

	update_lru_active(obj);

	mutex_unlock(&priv->lru.lock);

}



struct msm_gem_vma *msm_gem_get_vma_locked(struct drm_gem_object *obj,

					   struct msm_gem_address_space *aspace)

{

drivers/gpu/drm/msm/msm_gem.h

+1 −0
Original line number Diff line number Diff line
@@ -128,6 +128,7 @@ struct msm_gem_object { 
uint64_t msm_gem_mmap_offset(struct drm_gem_object *obj);

int msm_gem_pin_vma_locked(struct drm_gem_object *obj, struct msm_gem_vma *vma);

void msm_gem_unpin_locked(struct drm_gem_object *obj);

void msm_gem_unpin_active(struct drm_gem_object *obj);

struct msm_gem_vma *msm_gem_get_vma_locked(struct drm_gem_object *obj,

					   struct msm_gem_address_space *aspace);

int msm_gem_get_iova(struct drm_gem_object *obj,

drivers/gpu/drm/msm/msm_ringbuffer.c

+1 −3
Original line number Diff line number Diff line
@@ -24,9 +24,7 @@ static struct dma_fence *msm_job_run(struct drm_sched_job *job) 
		struct drm_gem_object *obj = &submit->bos[i].obj->base;



		msm_gem_vma_unpin_fenced(submit->bos[i].vma, fctx);

		msm_gem_lock(obj);

		msm_gem_unpin_locked(obj);

		msm_gem_unlock(obj);

		msm_gem_unpin_active(obj);

		submit->bos[i].flags &= ~(BO_VMA_PINNED | BO_OBJ_PINNED);

	}