diff mbox series

[v3,06/23] drm/msm/gem: Move locking in shrinker path

Message ID 20201019204636.139997-7-robdclark@gmail.com
State New, archived
Headers show
Series drm/msm: de-struct_mutex-ification | expand

Commit Message

Rob Clark Oct. 19, 2020, 8:46 p.m. UTC
From: Rob Clark <robdclark@chromium.org>

Move grabbing the bo lock into shrinker, with a msm_gem_trylock() to
skip over bo's that are already locked.  This gets rid of the nested
lock classes.

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/gpu/drm/msm/msm_gem.c          | 24 +++++----------------
 drivers/gpu/drm/msm/msm_gem.h          | 29 ++++++++++----------------
 drivers/gpu/drm/msm/msm_gem_shrinker.c | 27 +++++++++++++++++-------
 3 files changed, 35 insertions(+), 45 deletions(-)

Comments

Kristian Høgsberg Oct. 23, 2020, 8:55 a.m. UTC | #1
On Mon, Oct 19, 2020 at 10:45 PM Rob Clark <robdclark@gmail.com> wrote:
>
> From: Rob Clark <robdclark@chromium.org>
>
> Move grabbing the bo lock into shrinker, with a msm_gem_trylock() to
> skip over bo's that are already locked.  This gets rid of the nested
> lock classes.
>
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
>  drivers/gpu/drm/msm/msm_gem.c          | 24 +++++----------------
>  drivers/gpu/drm/msm/msm_gem.h          | 29 ++++++++++----------------
>  drivers/gpu/drm/msm/msm_gem_shrinker.c | 27 +++++++++++++++++-------
>  3 files changed, 35 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
> index e0d8d739b068..1195847714ba 100644
> --- a/drivers/gpu/drm/msm/msm_gem.c
> +++ b/drivers/gpu/drm/msm/msm_gem.c
> @@ -17,8 +17,6 @@
>  #include "msm_gpu.h"
>  #include "msm_mmu.h"
>
> -static void msm_gem_vunmap_locked(struct drm_gem_object *obj);
> -
>
>  static dma_addr_t physaddr(struct drm_gem_object *obj)
>  {
> @@ -693,20 +691,19 @@ int msm_gem_madvise(struct drm_gem_object *obj, unsigned madv)
>         return (madv != __MSM_MADV_PURGED);
>  }
>
> -void msm_gem_purge(struct drm_gem_object *obj, enum msm_gem_lock subclass)
> +void msm_gem_purge(struct drm_gem_object *obj)
>  {
>         struct drm_device *dev = obj->dev;
>         struct msm_gem_object *msm_obj = to_msm_bo(obj);
>
>         WARN_ON(!mutex_is_locked(&dev->struct_mutex));
> +       WARN_ON(!msm_gem_is_locked(obj));
>         WARN_ON(!is_purgeable(msm_obj));
>         WARN_ON(obj->import_attach);
>
> -       mutex_lock_nested(&msm_obj->lock, subclass);
> -
>         put_iova(obj);
>
> -       msm_gem_vunmap_locked(obj);
> +       msm_gem_vunmap(obj);
>
>         put_pages(obj);
>
> @@ -724,11 +721,9 @@ void msm_gem_purge(struct drm_gem_object *obj, enum msm_gem_lock subclass)
>
>         invalidate_mapping_pages(file_inode(obj->filp)->i_mapping,
>                         0, (loff_t)-1);
> -
> -       msm_gem_unlock(obj);
>  }
>
> -static void msm_gem_vunmap_locked(struct drm_gem_object *obj)
> +void msm_gem_vunmap(struct drm_gem_object *obj)
>  {
>         struct msm_gem_object *msm_obj = to_msm_bo(obj);
>
> @@ -741,15 +736,6 @@ static void msm_gem_vunmap_locked(struct drm_gem_object *obj)
>         msm_obj->vaddr = NULL;
>  }
>
> -void msm_gem_vunmap(struct drm_gem_object *obj, enum msm_gem_lock subclass)
> -{
> -       struct msm_gem_object *msm_obj = to_msm_bo(obj);
> -
> -       mutex_lock_nested(&msm_obj->lock, subclass);
> -       msm_gem_vunmap_locked(obj);
> -       msm_gem_unlock(obj);
> -}
> -
>  /* must be called before _move_to_active().. */
>  int msm_gem_sync_object(struct drm_gem_object *obj,
>                 struct msm_fence_context *fctx, bool exclusive)
> @@ -986,7 +972,7 @@ static void free_object(struct msm_gem_object *msm_obj)
>
>                 drm_prime_gem_destroy(obj, msm_obj->sgt);
>         } else {
> -               msm_gem_vunmap_locked(obj);
> +               msm_gem_vunmap(obj);
>                 put_pages(obj);
>         }
>
> diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
> index d55d5401a2d2..c5232b8da794 100644
> --- a/drivers/gpu/drm/msm/msm_gem.h
> +++ b/drivers/gpu/drm/msm/msm_gem.h
> @@ -162,6 +162,13 @@ msm_gem_lock(struct drm_gem_object *obj)
>         mutex_lock(&msm_obj->lock);
>  }
>
> +static inline bool __must_check
> +msm_gem_trylock(struct drm_gem_object *obj)
> +{
> +       struct msm_gem_object *msm_obj = to_msm_bo(obj);
> +       return mutex_trylock_recursive(&msm_obj->lock) == MUTEX_TRYLOCK_SUCCESS;

This can just be

    return mutex_trylock(&msm_obj->lock) == 1;

now, right?

> +}
> +
>  static inline int
>  msm_gem_lock_interruptible(struct drm_gem_object *obj)
>  {
> @@ -190,6 +197,7 @@ static inline bool is_active(struct msm_gem_object *msm_obj)
>
>  static inline bool is_purgeable(struct msm_gem_object *msm_obj)
>  {
> +       WARN_ON(!msm_gem_is_locked(&msm_obj->base));
>         WARN_ON(!mutex_is_locked(&msm_obj->base.dev->struct_mutex));
>         return (msm_obj->madv == MSM_MADV_DONTNEED) && msm_obj->sgt &&
>                         !msm_obj->base.dma_buf && !msm_obj->base.import_attach;
> @@ -197,27 +205,12 @@ static inline bool is_purgeable(struct msm_gem_object *msm_obj)
>
>  static inline bool is_vunmapable(struct msm_gem_object *msm_obj)
>  {
> +       WARN_ON(!msm_gem_is_locked(&msm_obj->base));
>         return (msm_obj->vmap_count == 0) && msm_obj->vaddr;
>  }
>
> -/* The shrinker can be triggered while we hold objA->lock, and need
> - * to grab objB->lock to purge it.  Lockdep just sees these as a single
> - * class of lock, so we use subclasses to teach it the difference.
> - *
> - * OBJ_LOCK_NORMAL is implicit (ie. normal mutex_lock() call), and
> - * OBJ_LOCK_SHRINKER is used by shrinker.
> - *
> - * It is *essential* that we never go down paths that could trigger the
> - * shrinker for a purgable object.  This is ensured by checking that
> - * msm_obj->madv == MSM_MADV_WILLNEED.
> - */
> -enum msm_gem_lock {
> -       OBJ_LOCK_NORMAL,
> -       OBJ_LOCK_SHRINKER,
> -};
> -
> -void msm_gem_purge(struct drm_gem_object *obj, enum msm_gem_lock subclass);
> -void msm_gem_vunmap(struct drm_gem_object *obj, enum msm_gem_lock subclass);
> +void msm_gem_purge(struct drm_gem_object *obj);
> +void msm_gem_vunmap(struct drm_gem_object *obj);
>  void msm_gem_free_work(struct work_struct *work);
>
>  /* Created per submit-ioctl, to track bo's and cmdstream bufs, etc,
> diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c
> index 482576d7a39a..2dc0ffa925b4 100644
> --- a/drivers/gpu/drm/msm/msm_gem_shrinker.c
> +++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
> @@ -52,8 +52,11 @@ msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
>                 return 0;
>
>         list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
> +               if (!msm_gem_trylock(&msm_obj->base))
> +                       continue;
>                 if (is_purgeable(msm_obj))
>                         count += msm_obj->base.size >> PAGE_SHIFT;
> +               msm_gem_unlock(&msm_obj->base);
>         }
>
>         if (unlock)
> @@ -78,10 +81,13 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
>         list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
>                 if (freed >= sc->nr_to_scan)
>                         break;
> +               if (!msm_gem_trylock(&msm_obj->base))
> +                       continue;
>                 if (is_purgeable(msm_obj)) {
> -                       msm_gem_purge(&msm_obj->base, OBJ_LOCK_SHRINKER);
> +                       msm_gem_purge(&msm_obj->base);
>                         freed += msm_obj->base.size >> PAGE_SHIFT;
>                 }
> +               msm_gem_unlock(&msm_obj->base);
>         }
>
>         if (unlock)
> @@ -107,15 +113,20 @@ msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
>                 return NOTIFY_DONE;
>
>         list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
> +               if (!msm_gem_trylock(&msm_obj->base))
> +                       continue;
>                 if (is_vunmapable(msm_obj)) {
> -                       msm_gem_vunmap(&msm_obj->base, OBJ_LOCK_SHRINKER);
> -                       /* since we don't know any better, lets bail after a few
> -                        * and if necessary the shrinker will be invoked again.
> -                        * Seems better than unmapping *everything*
> -                        */
> -                       if (++unmapped >= 15)
> -                               break;
> +                       msm_gem_vunmap(&msm_obj->base);
> +                       unmapped++;
>                 }
> +               msm_gem_unlock(&msm_obj->base);
> +
> +               /* since we don't know any better, lets bail after a few
> +                * and if necessary the shrinker will be invoked again.
> +                * Seems better than unmapping *everything*
> +                */
> +               if (++unmapped >= 15)
> +                       break;
>         }
>
>         if (unlock)
> --
> 2.26.2
>
> _______________________________________________
> Freedreno mailing list
> Freedreno@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/freedreno
Rob Clark Oct. 23, 2020, 2:46 p.m. UTC | #2
On Fri, Oct 23, 2020 at 1:55 AM Kristian Høgsberg <hoegsberg@gmail.com> wrote:
>
> On Mon, Oct 19, 2020 at 10:45 PM Rob Clark <robdclark@gmail.com> wrote:
> >
> > From: Rob Clark <robdclark@chromium.org>
> >
> > Move grabbing the bo lock into shrinker, with a msm_gem_trylock() to
> > skip over bo's that are already locked.  This gets rid of the nested
> > lock classes.
> >
> > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > ---
> >  drivers/gpu/drm/msm/msm_gem.c          | 24 +++++----------------
> >  drivers/gpu/drm/msm/msm_gem.h          | 29 ++++++++++----------------
> >  drivers/gpu/drm/msm/msm_gem_shrinker.c | 27 +++++++++++++++++-------
> >  3 files changed, 35 insertions(+), 45 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
> > index e0d8d739b068..1195847714ba 100644
> > --- a/drivers/gpu/drm/msm/msm_gem.c
> > +++ b/drivers/gpu/drm/msm/msm_gem.c
> > @@ -17,8 +17,6 @@
> >  #include "msm_gpu.h"
> >  #include "msm_mmu.h"
> >
> > -static void msm_gem_vunmap_locked(struct drm_gem_object *obj);
> > -
> >
> >  static dma_addr_t physaddr(struct drm_gem_object *obj)
> >  {
> > @@ -693,20 +691,19 @@ int msm_gem_madvise(struct drm_gem_object *obj, unsigned madv)
> >         return (madv != __MSM_MADV_PURGED);
> >  }
> >
> > -void msm_gem_purge(struct drm_gem_object *obj, enum msm_gem_lock subclass)
> > +void msm_gem_purge(struct drm_gem_object *obj)
> >  {
> >         struct drm_device *dev = obj->dev;
> >         struct msm_gem_object *msm_obj = to_msm_bo(obj);
> >
> >         WARN_ON(!mutex_is_locked(&dev->struct_mutex));
> > +       WARN_ON(!msm_gem_is_locked(obj));
> >         WARN_ON(!is_purgeable(msm_obj));
> >         WARN_ON(obj->import_attach);
> >
> > -       mutex_lock_nested(&msm_obj->lock, subclass);
> > -
> >         put_iova(obj);
> >
> > -       msm_gem_vunmap_locked(obj);
> > +       msm_gem_vunmap(obj);
> >
> >         put_pages(obj);
> >
> > @@ -724,11 +721,9 @@ void msm_gem_purge(struct drm_gem_object *obj, enum msm_gem_lock subclass)
> >
> >         invalidate_mapping_pages(file_inode(obj->filp)->i_mapping,
> >                         0, (loff_t)-1);
> > -
> > -       msm_gem_unlock(obj);
> >  }
> >
> > -static void msm_gem_vunmap_locked(struct drm_gem_object *obj)
> > +void msm_gem_vunmap(struct drm_gem_object *obj)
> >  {
> >         struct msm_gem_object *msm_obj = to_msm_bo(obj);
> >
> > @@ -741,15 +736,6 @@ static void msm_gem_vunmap_locked(struct drm_gem_object *obj)
> >         msm_obj->vaddr = NULL;
> >  }
> >
> > -void msm_gem_vunmap(struct drm_gem_object *obj, enum msm_gem_lock subclass)
> > -{
> > -       struct msm_gem_object *msm_obj = to_msm_bo(obj);
> > -
> > -       mutex_lock_nested(&msm_obj->lock, subclass);
> > -       msm_gem_vunmap_locked(obj);
> > -       msm_gem_unlock(obj);
> > -}
> > -
> >  /* must be called before _move_to_active().. */
> >  int msm_gem_sync_object(struct drm_gem_object *obj,
> >                 struct msm_fence_context *fctx, bool exclusive)
> > @@ -986,7 +972,7 @@ static void free_object(struct msm_gem_object *msm_obj)
> >
> >                 drm_prime_gem_destroy(obj, msm_obj->sgt);
> >         } else {
> > -               msm_gem_vunmap_locked(obj);
> > +               msm_gem_vunmap(obj);
> >                 put_pages(obj);
> >         }
> >
> > diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
> > index d55d5401a2d2..c5232b8da794 100644
> > --- a/drivers/gpu/drm/msm/msm_gem.h
> > +++ b/drivers/gpu/drm/msm/msm_gem.h
> > @@ -162,6 +162,13 @@ msm_gem_lock(struct drm_gem_object *obj)
> >         mutex_lock(&msm_obj->lock);
> >  }
> >
> > +static inline bool __must_check
> > +msm_gem_trylock(struct drm_gem_object *obj)
> > +{
> > +       struct msm_gem_object *msm_obj = to_msm_bo(obj);
> > +       return mutex_trylock_recursive(&msm_obj->lock) == MUTEX_TRYLOCK_SUCCESS;
>
> This can just be
>
>     return mutex_trylock(&msm_obj->lock) == 1;
>
> now, right?

yeah, I suppose.. although this is just transient and gets replaced in
a later patch

BR,
-R

> > +}
> > +
> >  static inline int
> >  msm_gem_lock_interruptible(struct drm_gem_object *obj)
> >  {
> > @@ -190,6 +197,7 @@ static inline bool is_active(struct msm_gem_object *msm_obj)
> >
> >  static inline bool is_purgeable(struct msm_gem_object *msm_obj)
> >  {
> > +       WARN_ON(!msm_gem_is_locked(&msm_obj->base));
> >         WARN_ON(!mutex_is_locked(&msm_obj->base.dev->struct_mutex));
> >         return (msm_obj->madv == MSM_MADV_DONTNEED) && msm_obj->sgt &&
> >                         !msm_obj->base.dma_buf && !msm_obj->base.import_attach;
> > @@ -197,27 +205,12 @@ static inline bool is_purgeable(struct msm_gem_object *msm_obj)
> >
> >  static inline bool is_vunmapable(struct msm_gem_object *msm_obj)
> >  {
> > +       WARN_ON(!msm_gem_is_locked(&msm_obj->base));
> >         return (msm_obj->vmap_count == 0) && msm_obj->vaddr;
> >  }
> >
> > -/* The shrinker can be triggered while we hold objA->lock, and need
> > - * to grab objB->lock to purge it.  Lockdep just sees these as a single
> > - * class of lock, so we use subclasses to teach it the difference.
> > - *
> > - * OBJ_LOCK_NORMAL is implicit (ie. normal mutex_lock() call), and
> > - * OBJ_LOCK_SHRINKER is used by shrinker.
> > - *
> > - * It is *essential* that we never go down paths that could trigger the
> > - * shrinker for a purgable object.  This is ensured by checking that
> > - * msm_obj->madv == MSM_MADV_WILLNEED.
> > - */
> > -enum msm_gem_lock {
> > -       OBJ_LOCK_NORMAL,
> > -       OBJ_LOCK_SHRINKER,
> > -};
> > -
> > -void msm_gem_purge(struct drm_gem_object *obj, enum msm_gem_lock subclass);
> > -void msm_gem_vunmap(struct drm_gem_object *obj, enum msm_gem_lock subclass);
> > +void msm_gem_purge(struct drm_gem_object *obj);
> > +void msm_gem_vunmap(struct drm_gem_object *obj);
> >  void msm_gem_free_work(struct work_struct *work);
> >
> >  /* Created per submit-ioctl, to track bo's and cmdstream bufs, etc,
> > diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c
> > index 482576d7a39a..2dc0ffa925b4 100644
> > --- a/drivers/gpu/drm/msm/msm_gem_shrinker.c
> > +++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
> > @@ -52,8 +52,11 @@ msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
> >                 return 0;
> >
> >         list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
> > +               if (!msm_gem_trylock(&msm_obj->base))
> > +                       continue;
> >                 if (is_purgeable(msm_obj))
> >                         count += msm_obj->base.size >> PAGE_SHIFT;
> > +               msm_gem_unlock(&msm_obj->base);
> >         }
> >
> >         if (unlock)
> > @@ -78,10 +81,13 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
> >         list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
> >                 if (freed >= sc->nr_to_scan)
> >                         break;
> > +               if (!msm_gem_trylock(&msm_obj->base))
> > +                       continue;
> >                 if (is_purgeable(msm_obj)) {
> > -                       msm_gem_purge(&msm_obj->base, OBJ_LOCK_SHRINKER);
> > +                       msm_gem_purge(&msm_obj->base);
> >                         freed += msm_obj->base.size >> PAGE_SHIFT;
> >                 }
> > +               msm_gem_unlock(&msm_obj->base);
> >         }
> >
> >         if (unlock)
> > @@ -107,15 +113,20 @@ msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
> >                 return NOTIFY_DONE;
> >
> >         list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
> > +               if (!msm_gem_trylock(&msm_obj->base))
> > +                       continue;
> >                 if (is_vunmapable(msm_obj)) {
> > -                       msm_gem_vunmap(&msm_obj->base, OBJ_LOCK_SHRINKER);
> > -                       /* since we don't know any better, lets bail after a few
> > -                        * and if necessary the shrinker will be invoked again.
> > -                        * Seems better than unmapping *everything*
> > -                        */
> > -                       if (++unmapped >= 15)
> > -                               break;
> > +                       msm_gem_vunmap(&msm_obj->base);
> > +                       unmapped++;
> >                 }
> > +               msm_gem_unlock(&msm_obj->base);
> > +
> > +               /* since we don't know any better, lets bail after a few
> > +                * and if necessary the shrinker will be invoked again.
> > +                * Seems better than unmapping *everything*
> > +                */
> > +               if (++unmapped >= 15)
> > +                       break;
> >         }
> >
> >         if (unlock)
> > --
> > 2.26.2
> >
> > _______________________________________________
> > Freedreno mailing list
> > Freedreno@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/freedreno
diff mbox series

Patch

diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index e0d8d739b068..1195847714ba 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -17,8 +17,6 @@ 
 #include "msm_gpu.h"
 #include "msm_mmu.h"
 
-static void msm_gem_vunmap_locked(struct drm_gem_object *obj);
-
 
 static dma_addr_t physaddr(struct drm_gem_object *obj)
 {
@@ -693,20 +691,19 @@  int msm_gem_madvise(struct drm_gem_object *obj, unsigned madv)
 	return (madv != __MSM_MADV_PURGED);
 }
 
-void msm_gem_purge(struct drm_gem_object *obj, enum msm_gem_lock subclass)
+void msm_gem_purge(struct drm_gem_object *obj)
 {
 	struct drm_device *dev = obj->dev;
 	struct msm_gem_object *msm_obj = to_msm_bo(obj);
 
 	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
+	WARN_ON(!msm_gem_is_locked(obj));
 	WARN_ON(!is_purgeable(msm_obj));
 	WARN_ON(obj->import_attach);
 
-	mutex_lock_nested(&msm_obj->lock, subclass);
-
 	put_iova(obj);
 
-	msm_gem_vunmap_locked(obj);
+	msm_gem_vunmap(obj);
 
 	put_pages(obj);
 
@@ -724,11 +721,9 @@  void msm_gem_purge(struct drm_gem_object *obj, enum msm_gem_lock subclass)
 
 	invalidate_mapping_pages(file_inode(obj->filp)->i_mapping,
 			0, (loff_t)-1);
-
-	msm_gem_unlock(obj);
 }
 
-static void msm_gem_vunmap_locked(struct drm_gem_object *obj)
+void msm_gem_vunmap(struct drm_gem_object *obj)
 {
 	struct msm_gem_object *msm_obj = to_msm_bo(obj);
 
@@ -741,15 +736,6 @@  static void msm_gem_vunmap_locked(struct drm_gem_object *obj)
 	msm_obj->vaddr = NULL;
 }
 
-void msm_gem_vunmap(struct drm_gem_object *obj, enum msm_gem_lock subclass)
-{
-	struct msm_gem_object *msm_obj = to_msm_bo(obj);
-
-	mutex_lock_nested(&msm_obj->lock, subclass);
-	msm_gem_vunmap_locked(obj);
-	msm_gem_unlock(obj);
-}
-
 /* must be called before _move_to_active().. */
 int msm_gem_sync_object(struct drm_gem_object *obj,
 		struct msm_fence_context *fctx, bool exclusive)
@@ -986,7 +972,7 @@  static void free_object(struct msm_gem_object *msm_obj)
 
 		drm_prime_gem_destroy(obj, msm_obj->sgt);
 	} else {
-		msm_gem_vunmap_locked(obj);
+		msm_gem_vunmap(obj);
 		put_pages(obj);
 	}
 
diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
index d55d5401a2d2..c5232b8da794 100644
--- a/drivers/gpu/drm/msm/msm_gem.h
+++ b/drivers/gpu/drm/msm/msm_gem.h
@@ -162,6 +162,13 @@  msm_gem_lock(struct drm_gem_object *obj)
 	mutex_lock(&msm_obj->lock);
 }
 
+static inline bool __must_check
+msm_gem_trylock(struct drm_gem_object *obj)
+{
+	struct msm_gem_object *msm_obj = to_msm_bo(obj);
+	return mutex_trylock_recursive(&msm_obj->lock) == MUTEX_TRYLOCK_SUCCESS;
+}
+
 static inline int
 msm_gem_lock_interruptible(struct drm_gem_object *obj)
 {
@@ -190,6 +197,7 @@  static inline bool is_active(struct msm_gem_object *msm_obj)
 
 static inline bool is_purgeable(struct msm_gem_object *msm_obj)
 {
+	WARN_ON(!msm_gem_is_locked(&msm_obj->base));
 	WARN_ON(!mutex_is_locked(&msm_obj->base.dev->struct_mutex));
 	return (msm_obj->madv == MSM_MADV_DONTNEED) && msm_obj->sgt &&
 			!msm_obj->base.dma_buf && !msm_obj->base.import_attach;
@@ -197,27 +205,12 @@  static inline bool is_purgeable(struct msm_gem_object *msm_obj)
 
 static inline bool is_vunmapable(struct msm_gem_object *msm_obj)
 {
+	WARN_ON(!msm_gem_is_locked(&msm_obj->base));
 	return (msm_obj->vmap_count == 0) && msm_obj->vaddr;
 }
 
-/* The shrinker can be triggered while we hold objA->lock, and need
- * to grab objB->lock to purge it.  Lockdep just sees these as a single
- * class of lock, so we use subclasses to teach it the difference.
- *
- * OBJ_LOCK_NORMAL is implicit (ie. normal mutex_lock() call), and
- * OBJ_LOCK_SHRINKER is used by shrinker.
- *
- * It is *essential* that we never go down paths that could trigger the
- * shrinker for a purgable object.  This is ensured by checking that
- * msm_obj->madv == MSM_MADV_WILLNEED.
- */
-enum msm_gem_lock {
-	OBJ_LOCK_NORMAL,
-	OBJ_LOCK_SHRINKER,
-};
-
-void msm_gem_purge(struct drm_gem_object *obj, enum msm_gem_lock subclass);
-void msm_gem_vunmap(struct drm_gem_object *obj, enum msm_gem_lock subclass);
+void msm_gem_purge(struct drm_gem_object *obj);
+void msm_gem_vunmap(struct drm_gem_object *obj);
 void msm_gem_free_work(struct work_struct *work);
 
 /* Created per submit-ioctl, to track bo's and cmdstream bufs, etc,
diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c
index 482576d7a39a..2dc0ffa925b4 100644
--- a/drivers/gpu/drm/msm/msm_gem_shrinker.c
+++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
@@ -52,8 +52,11 @@  msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
 		return 0;
 
 	list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
+		if (!msm_gem_trylock(&msm_obj->base))
+			continue;
 		if (is_purgeable(msm_obj))
 			count += msm_obj->base.size >> PAGE_SHIFT;
+		msm_gem_unlock(&msm_obj->base);
 	}
 
 	if (unlock)
@@ -78,10 +81,13 @@  msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
 	list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
 		if (freed >= sc->nr_to_scan)
 			break;
+		if (!msm_gem_trylock(&msm_obj->base))
+			continue;
 		if (is_purgeable(msm_obj)) {
-			msm_gem_purge(&msm_obj->base, OBJ_LOCK_SHRINKER);
+			msm_gem_purge(&msm_obj->base);
 			freed += msm_obj->base.size >> PAGE_SHIFT;
 		}
+		msm_gem_unlock(&msm_obj->base);
 	}
 
 	if (unlock)
@@ -107,15 +113,20 @@  msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
 		return NOTIFY_DONE;
 
 	list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
+		if (!msm_gem_trylock(&msm_obj->base))
+			continue;
 		if (is_vunmapable(msm_obj)) {
-			msm_gem_vunmap(&msm_obj->base, OBJ_LOCK_SHRINKER);
-			/* since we don't know any better, lets bail after a few
-			 * and if necessary the shrinker will be invoked again.
-			 * Seems better than unmapping *everything*
-			 */
-			if (++unmapped >= 15)
-				break;
+			msm_gem_vunmap(&msm_obj->base);
+			unmapped++;
 		}
+		msm_gem_unlock(&msm_obj->base);
+
+		/* since we don't know any better, lets bail after a few
+		 * and if necessary the shrinker will be invoked again.
+		 * Seems better than unmapping *everything*
+		 */
+		if (++unmapped >= 15)
+			break;
 	}
 
 	if (unlock)