| Message ID | 20230724094354.90817-25-zhengqi.arch@bytedance.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | use refcount+RCU method to implement lockless slab shrink | expand |
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. > + 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); > }
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); >> } >
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); + 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); }
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> --- 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(-)