[Linaro-mm-sig] Re: [PATCH v6 22/22] drm/panfrost: Switch to generic memory shrinker

Acked-by: Alyssa Rosenzweig alyssa.rosenzweig@collabora.com

On Fri, May 27, 2022 at 02:50:40AM +0300, Dmitry Osipenko wrote:

Replace Panfrost's memory shrinker with a generic drm-shmem memory shrinker.

Tested-by: Steven Price steven.price@arm.com Signed-off-by: Dmitry Osipenko dmitry.osipenko@collabora.com

---

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 | 33 +++-- drivers/gpu/drm/panfrost/panfrost_gem.h | 9 -- .../gpu/drm/panfrost/panfrost_gem_shrinker.c | 129 ------------------ drivers/gpu/drm/panfrost/panfrost_job.c | 18 ++- 7 files changed, 42 insertions(+), 171 deletions(-) delete mode 100644 drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c

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 859e240161d1..b77c99ba2475 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; }

@@ -392,7 +391,6 @@ 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;

@@ -409,7 +407,6 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data, if (ret) goto out_put_object;

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

@@ -435,17 +432,8 @@ 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_move_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); dma_resv_unlock(bo->base.base.resv);

out_put_object: drm_gem_object_put(gem_obj); @@ -577,9 +565,6 @@ 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)

@@ -601,7 +586,7 @@ 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; @@ -619,8 +604,8 @@ 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..f1436405e3a0 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.

@@ -209,6 +199,25 @@ static const struct drm_gem_object_funcs panfrost_gem_funcs = { .vm_ops = &drm_gem_shmem_vm_ops, }; +static int panfrost_shmem_evict(struct drm_gem_shmem_object *shmem) +{

• struct panfrost_gem_object *bo = to_panfrost_bo(&shmem->base);
• if (!drm_gem_shmem_is_purgeable(shmem))

• return -EOPNOTSUPP;
  

• if (!mutex_trylock(&bo->mappings.lock))

• return -EBUSY;
  

• panfrost_gem_teardown_mappings_locked(bo);
• drm_gem_shmem_purge(shmem);
• mutex_unlock(&bo->mappings.lock);
• return 0;

+}

/**

• panfrost_gem_create_object - Implementation of driver->gem_create_object.
• @dev: DRM device

@@ -230,6 +239,7 @@ struct drm_gem_object *panfrost_gem_create_object(struct drm_device *dev, size_t mutex_init(&obj->mappings.lock); obj->base.base.funcs = &panfrost_gem_funcs; obj->base.map_wc = !pfdev->coherent;

• obj->base.evict = panfrost_shmem_evict;

return &obj->base.base; } @@ -266,6 +276,9 @@ panfrost_gem_create_with_handle(struct drm_file *file_priv, if (ret) return ERR_PTR(ret);

• if (!bo->is_heap)

• drm_gem_shmem_set_purgeable(shmem);
  

• return bo;

} 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_gem_shrinker.c b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c deleted file mode 100644 index 7cc32556f908..000000000000 --- a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c +++ /dev/null @@ -1,129 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* Copyright (C) 2019 Arm Ltd.

• • Based on msm_gem_freedreno.c:
• • Copyright (C) 2016 Red Hat
• • Author: Rob Clark robdclark@gmail.com
• */

-#include <linux/list.h>

-#include <drm/drm_device.h> -#include <drm/drm_gem_shmem_helper.h>

-#include "panfrost_device.h" -#include "panfrost_gem.h" -#include "panfrost_mmu.h"

-static bool panfrost_gem_shmem_is_purgeable(struct drm_gem_shmem_object *shmem) -{

• return (shmem->madv > 0) &&

• !shmem->pages_pin_count && shmem->sgt &&
  

• !shmem->base.dma_buf && !shmem->base.import_attach;
  

-}

-static unsigned long -panfrost_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc) -{

• struct panfrost_device *pfdev =

• container_of(shrinker, struct panfrost_device, shrinker);
  

• struct drm_gem_shmem_object *shmem;
• unsigned long count = 0;
• if (!mutex_trylock(&pfdev->shrinker_lock))

• return 0;
  

• list_for_each_entry(shmem, &pfdev->shrinker_list, madv_list) {

• if (panfrost_gem_shmem_is_purgeable(shmem))
  

• 	count += shmem->base.size >> PAGE_SHIFT;
  

• }
• mutex_unlock(&pfdev->shrinker_lock);
• return count;

-}

-static bool 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);
• bool ret = false;
• if (atomic_read(&bo->gpu_usecount))

• return false;
  

• if (!mutex_trylock(&bo->mappings.lock))

• return false;
  

• if (!dma_resv_trylock(shmem->base.resv))

• goto unlock_mappings;
  

• panfrost_gem_teardown_mappings_locked(bo);
• drm_gem_shmem_purge(&bo->base);
• ret = true;
• dma_resv_unlock(shmem->base.resv);

-unlock_mappings:

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

-}

-static unsigned long -panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) -{

• struct panfrost_device *pfdev =

• container_of(shrinker, struct panfrost_device, shrinker);
  

• struct drm_gem_shmem_object *shmem, *tmp;
• unsigned long freed = 0;
• if (!mutex_trylock(&pfdev->shrinker_lock))

• return SHRINK_STOP;
  

• list_for_each_entry_safe(shmem, tmp, &pfdev->shrinker_list, madv_list) {

• if (freed >= sc->nr_to_scan)
  

• 	break;
  

• if (drm_gem_shmem_is_purgeable(shmem) &&
  

•     panfrost_gem_purge(&shmem->base)) {
  

• 	freed += shmem->base.size >> PAGE_SHIFT;
  

• 	list_del_init(&shmem->madv_list);
  

• }
  

• }
• mutex_unlock(&pfdev->shrinker_lock);
• if (freed > 0)

• pr_info_ratelimited("Purging %lu bytes\n", freed << PAGE_SHIFT);
  

• return freed;

-}

-/**

• • panfrost_gem_shrinker_init - Initialize panfrost shrinker
• • @dev: DRM device
• • This function registers and sets up the panfrost shrinker.
• */

-void panfrost_gem_shrinker_init(struct drm_device *dev) -{

• struct panfrost_device *pfdev = dev->dev_private;
• pfdev->shrinker.count_objects = panfrost_gem_shrinker_count;
• pfdev->shrinker.scan_objects = panfrost_gem_shrinker_scan;
• pfdev->shrinker.seeks = DEFAULT_SEEKS;
• WARN_ON(register_shrinker(&pfdev->shrinker));

-}

-/**

• • panfrost_gem_shrinker_cleanup - Clean up panfrost shrinker
• • @dev: DRM device
• • This function unregisters the panfrost shrinker.
• */

-void panfrost_gem_shrinker_cleanup(struct drm_device *dev) -{

• struct panfrost_device *pfdev = dev->dev_private;
• if (pfdev->shrinker.nr_deferred) {

• unregister_shrinker(&pfdev->shrinker);
  

• }

-} diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c index 7c4208476fbd..5c327a79455f 100644 --- a/drivers/gpu/drm/panfrost/panfrost_job.c +++ b/drivers/gpu/drm/panfrost/panfrost_job.c @@ -271,6 +271,19 @@ static void panfrost_attach_object_fences(struct drm_gem_object **bos, dma_resv_add_fence(bos[i]->resv, fence, DMA_RESV_USAGE_WRITE); } +static int panfrost_objects_prepare(struct drm_gem_object **bos, int bo_count) +{

• struct panfrost_gem_object *bo;
• int ret = 0;
• while (!ret && bo_count--) {

• bo = to_panfrost_bo(bos[bo_count]);
  

• ret = bo->base.madv ? -ENOMEM : 0;
  

• }
• return ret;

+}

int panfrost_job_push(struct panfrost_job *job) { struct panfrost_device *pfdev = job->pfdev; @@ -282,6 +295,10 @@ int panfrost_job_push(struct panfrost_job *job) if (ret) return ret;

• ret = panfrost_objects_prepare(job->bos, job->bo_count);
• if (ret)

• goto unlock;
  

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

@@ -323,7 +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);

-- 2.35.3