Re: [PATCH v2 8/8] drm/panfrost: Switch to generic memory shrinker

On 14/03/2022 22:42, Dmitry Osipenko wrote:

Replace Panfrost's memory shrinker with a generic DRM memory shrinker.

Signed-off-by: Dmitry Osipenko dmitry.osipenko@collabora.com

I gave this a spin on my Firefly-RK3288 board and everything seems to work. So feel free to add a:

Tested-by: Steven Price steven.price@arm.com

As Alyssa has already pointed out you need to remove the panfrost_gem_shrinker.c file. But otherwise everything looks fine, and I'm very happy to see the shrinker code gone ;)

Thanks,

Steve

drivers/gpu/drm/panfrost/Makefile | 1 - drivers/gpu/drm/panfrost/panfrost_device.h | 4 ---- drivers/gpu/drm/panfrost/panfrost_drv.c | 19 ++------------- drivers/gpu/drm/panfrost/panfrost_gem.c | 27 ++++++++++++++-------- drivers/gpu/drm/panfrost/panfrost_gem.h | 9 -------- drivers/gpu/drm/panfrost/panfrost_job.c | 22 +++++++++++++++++- 6 files changed, 40 insertions(+), 42 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/Makefile b/drivers/gpu/drm/panfrost/Makefile index b71935862417..ecf0864cb515 100644 --- a/drivers/gpu/drm/panfrost/Makefile +++ b/drivers/gpu/drm/panfrost/Makefile @@ -5,7 +5,6 @@ panfrost-y := \ panfrost_device.o \ panfrost_devfreq.o \ panfrost_gem.o \

• panfrost_gem_shrinker.o \ panfrost_gpu.o \ panfrost_job.o \ panfrost_mmu.o \

diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h index 8b25278f34c8..fe04b21fc044 100644 --- a/drivers/gpu/drm/panfrost/panfrost_device.h +++ b/drivers/gpu/drm/panfrost/panfrost_device.h @@ -115,10 +115,6 @@ struct panfrost_device { atomic_t pending; } reset;

• struct mutex shrinker_lock;
• struct list_head shrinker_list;
• struct shrinker shrinker;
• struct panfrost_devfreq pfdevfreq;

};

diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c index 94b6f0a19c83..b014dadcf51f 100644 --- a/drivers/gpu/drm/panfrost/panfrost_drv.c +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c @@ -160,7 +160,6 @@ panfrost_lookup_bos(struct drm_device *dev, break; }

• atomic_inc(&bo->gpu_usecount);
  

  job->mappings[i] = mapping; }

@@ -390,7 +389,6 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data, { struct panfrost_file_priv *priv = file_priv->driver_priv; struct drm_panfrost_madvise *args = data;

• struct panfrost_device *pfdev = dev->dev_private; struct drm_gem_object *gem_obj; struct panfrost_gem_object *bo; int ret = 0;

@@ -403,7 +401,6 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,

bo = to_panfrost_bo(gem_obj);

• mutex_lock(&pfdev->shrinker_lock); mutex_lock(&bo->mappings.lock); if (args->madv == PANFROST_MADV_DONTNEED) { struct panfrost_gem_mapping *first;

@@ -429,17 +426,8 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,

args->retained = drm_gem_shmem_madvise(&bo->base, args->madv);

• if (args->retained) {

• if (args->madv == PANFROST_MADV_DONTNEED)
  

• 	list_add_tail(&bo->base.madv_list,
  

• 		      &pfdev->shrinker_list);
  

• else if (args->madv == PANFROST_MADV_WILLNEED)
  

• 	list_del_init(&bo->base.madv_list);
  

• }

out_unlock_mappings: mutex_unlock(&bo->mappings.lock);

• mutex_unlock(&pfdev->shrinker_lock);

  drm_gem_object_put(gem_obj); return ret;

@@ -570,9 +558,6 @@ static int panfrost_probe(struct platform_device *pdev) ddev->dev_private = pfdev; pfdev->ddev = ddev;

• mutex_init(&pfdev->shrinker_lock);
• INIT_LIST_HEAD(&pfdev->shrinker_list);
• err = panfrost_device_init(pfdev); if (err) { if (err != -EPROBE_DEFER)

@@ -594,7 +579,7 @@ static int panfrost_probe(struct platform_device *pdev) if (err < 0) goto err_out1;

• panfrost_gem_shrinker_init(ddev);

• drm_gem_shmem_shrinker_register(ddev);

  return 0;

@@ -612,8 +597,8 @@ static int panfrost_remove(struct platform_device *pdev) struct panfrost_device *pfdev = platform_get_drvdata(pdev); struct drm_device *ddev = pfdev->ddev;

• drm_gem_shmem_shrinker_unregister(ddev); drm_dev_unregister(ddev);

• panfrost_gem_shrinker_cleanup(ddev);

  pm_runtime_get_sync(pfdev->dev); pm_runtime_disable(pfdev->dev);

diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c index 293e799e2fe8..d164d05ed84e 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c @@ -19,16 +19,6 @@ static void panfrost_gem_free_object(struct drm_gem_object *obj) struct panfrost_gem_object *bo = to_panfrost_bo(obj); struct panfrost_device *pfdev = obj->dev->dev_private;

• /*

• * Make sure the BO is no longer inserted in the shrinker list before
  

• * taking care of the destruction itself. If we don't do that we have a
  

• * race condition between this function and what's done in
  

• * panfrost_gem_shrinker_scan().
  

• */
  

• mutex_lock(&pfdev->shrinker_lock);
• list_del_init(&bo->base.madv_list);
• mutex_unlock(&pfdev->shrinker_lock);
• /*
  • If we still have mappings attached to the BO, there's a problem in
  • our refcounting.

@@ -195,6 +185,22 @@ static int panfrost_gem_pin(struct drm_gem_object *obj) return drm_gem_shmem_pin(&bo->base); }

+static unsigned long panfrost_gem_purge(struct drm_gem_object *obj) +{

• struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
• struct panfrost_gem_object *bo = to_panfrost_bo(obj);
• if (!mutex_trylock(&bo->mappings.lock))

• return 0;
  

• panfrost_gem_teardown_mappings_locked(bo);
• drm_gem_shmem_purge_locked(&bo->base);
• mutex_unlock(&bo->mappings.lock);
• return shmem->base.size >> PAGE_SHIFT;

+}

static const struct drm_gem_object_funcs panfrost_gem_funcs = { .free = panfrost_gem_free_object, .open = panfrost_gem_open, @@ -207,6 +213,7 @@ static const struct drm_gem_object_funcs panfrost_gem_funcs = { .vunmap = drm_gem_shmem_object_vunmap, .mmap = drm_gem_shmem_object_mmap, .vm_ops = &drm_gem_shmem_vm_ops,

• .purge = panfrost_gem_purge,

};

/** diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h index 8088d5fd8480..09da064f1c07 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.h +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h @@ -30,12 +30,6 @@ struct panfrost_gem_object { struct mutex lock; } mappings;

• /*

• * Count the number of jobs referencing this BO so we don't let the
  

• * shrinker reclaim this object prematurely.
  

• */
  

• atomic_t gpu_usecount;
• bool noexec :1; bool is_heap :1;

}; @@ -84,7 +78,4 @@ panfrost_gem_mapping_get(struct panfrost_gem_object *bo, void panfrost_gem_mapping_put(struct panfrost_gem_mapping *mapping); void panfrost_gem_teardown_mappings_locked(struct panfrost_gem_object *bo);

-void panfrost_gem_shrinker_init(struct drm_device *dev); -void panfrost_gem_shrinker_cleanup(struct drm_device *dev);

#endif /* __PANFROST_GEM_H__ */ diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c index a6925dbb6224..e767e526e897 100644 --- a/drivers/gpu/drm/panfrost/panfrost_job.c +++ b/drivers/gpu/drm/panfrost/panfrost_job.c @@ -267,6 +267,22 @@ static void panfrost_attach_object_fences(struct drm_gem_object **bos, dma_resv_add_excl_fence(bos[i]->resv, fence); }

+static bool panfrost_objects_alive(struct drm_gem_object **bos, int bo_count) +{

• struct panfrost_gem_object *bo;
• bool alive = true;
• while (alive && bo_count--) {

• bo = to_panfrost_bo(bos[bo_count]);
  

• mutex_lock(&bo->mappings.lock);
  

• alive = !bo->base.madv;
  

• mutex_unlock(&bo->mappings.lock);
  

• }
• return alive;

+}

int panfrost_job_push(struct panfrost_job *job) { struct panfrost_device *pfdev = job->pfdev; @@ -278,6 +294,11 @@ int panfrost_job_push(struct panfrost_job *job) if (ret) return ret;

• if (!panfrost_objects_alive(job->bos, job->bo_count)) {

• ret = -ENOMEM;
  

• goto unlock;
  

• }
• mutex_lock(&pfdev->sched_lock); drm_sched_job_arm(&job->base);

@@ -319,7 +340,6 @@ static void panfrost_job_cleanup(struct kref *ref) if (!job->mappings[i]) break;

• 	atomic_dec(&job->mappings[i]->obj->gpu_usecount);
  panfrost_gem_mapping_put(job->mappings[i]);
  

  } kvfree(job->mappings);