Messages in this thread | | | Date | Tue, 25 Jul 2023 11:05:04 +0800 | Subject | Re: [PATCH v2 24/47] drm/panfrost: dynamically allocate the drm-panfrost shrinker | From | Qi Zheng <> |
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Hi Steven,
On 2023/7/24 19:17, Steven Price wrote: > On 24/07/2023 10:43, Qi Zheng wrote: >> In preparation for implementing lockless slab shrink, use new APIs to >> dynamically allocate the drm-panfrost shrinker, so that it can be freed >> asynchronously using kfree_rcu(). Then it doesn't need to wait for RCU >> read-side critical section when releasing the struct panfrost_device. >> >> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> > > One nit below, but otherwise: > > Reviewed-by: Steven Price <steven.price@arm.com> > >> --- >> drivers/gpu/drm/panfrost/panfrost_device.h | 2 +- >> drivers/gpu/drm/panfrost/panfrost_drv.c | 6 +++- >> drivers/gpu/drm/panfrost/panfrost_gem.h | 2 +- >> .../gpu/drm/panfrost/panfrost_gem_shrinker.c | 32 ++++++++++++------- >> 4 files changed, 27 insertions(+), 15 deletions(-) >> >> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h >> index b0126b9fbadc..e667e5689353 100644 >> --- a/drivers/gpu/drm/panfrost/panfrost_device.h >> +++ b/drivers/gpu/drm/panfrost/panfrost_device.h >> @@ -118,7 +118,7 @@ struct panfrost_device { >> >> struct mutex shrinker_lock; >> struct list_head shrinker_list; >> - struct shrinker shrinker; >> + 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 bbada731bbbd..f705bbdea360 100644 >> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c >> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c >> @@ -598,10 +598,14 @@ static int panfrost_probe(struct platform_device *pdev) >> if (err < 0) >> goto err_out1; >> >> - panfrost_gem_shrinker_init(ddev); >> + err = panfrost_gem_shrinker_init(ddev); >> + if (err) >> + goto err_out2; >> >> return 0; >> >> +err_out2: >> + drm_dev_unregister(ddev); >> err_out1: >> pm_runtime_disable(pfdev->dev); >> panfrost_device_fini(pfdev); >> diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h >> index ad2877eeeccd..863d2ec8d4f0 100644 >> --- a/drivers/gpu/drm/panfrost/panfrost_gem.h >> +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h >> @@ -81,7 +81,7 @@ 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); >> +int 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 >> index bf0170782f25..9a90dfb5301f 100644 >> --- a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c >> +++ b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c >> @@ -18,8 +18,7 @@ >> 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 panfrost_device *pfdev = shrinker->private_data; >> struct drm_gem_shmem_object *shmem; >> unsigned long count = 0; >> >> @@ -65,8 +64,7 @@ static bool panfrost_gem_purge(struct drm_gem_object *obj) >> 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 panfrost_device *pfdev = shrinker->private_data; >> struct drm_gem_shmem_object *shmem, *tmp; >> unsigned long freed = 0; >> >> @@ -97,13 +95,24 @@ panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) >> * >> * This function registers and sets up the panfrost shrinker. >> */ >> -void panfrost_gem_shrinker_init(struct drm_device *dev) >> +int 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, "drm-panfrost")); >> + >> + pfdev->shrinker = shrinker_alloc(0, "drm-panfrost"); >> + if (!pfdev->shrinker) { >> + WARN_ON(1); > > I don't think this WARN_ON is particularly useful - if there's a failed > memory allocation we should see output from the kernel anyway. And we're > changing the semantics from "continue just without a shrinker" (which > argueably justifies the warning) to "probe fails, device doesn't work" > which will be obvious to the user so I don't feel we need the additional > warn.
Make sense. Will delete this WARN_ON() in the next version.
Thanks, Qi
> >> + return -ENOMEM; >> + } >> + >> + pfdev->shrinker->count_objects = panfrost_gem_shrinker_count; >> + pfdev->shrinker->scan_objects = panfrost_gem_shrinker_scan; >> + pfdev->shrinker->seeks = DEFAULT_SEEKS; >> + pfdev->shrinker->private_data = pfdev; >> + >> + shrinker_register(pfdev->shrinker); >> + >> + return 0; >> } >> >> /** >> @@ -116,7 +125,6 @@ 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); >> - } >> + if (pfdev->shrinker) >> + shrinker_unregister(pfdev->shrinker); >> } >
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