The vmapped pages shall be pinned in memory and previously get/put_pages()
were implicitly hard-pinning/unpinning the pages. This will no longer be
the case with addition of memory shrinker because pages_use_count > 0 won't
determine anymore whether pages are hard-pinned (they will be soft-pinned),
while the new pages_pin_count will do the hard-pinning. Switch the
vmap/vunmap() to use pin/unpin() functions in a preparation of addition
of the memory shrinker support to drm-shmem.
Reviewed-by: Boris Brezillon <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/gpu/drm/drm_gem_shmem_helper.c | 19 ++++++++++++-------
include/drm/drm_gem_shmem_helper.h | 2 +-
2 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 41b749bedb11..6f963c2c1ecc 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -256,6 +256,14 @@ static int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem)
return ret;
}
+static void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem)
+{
+ dma_resv_assert_held(shmem->base.resv);
+
+ if (refcount_dec_and_test(&shmem->pages_pin_count))
+ drm_gem_shmem_put_pages_locked(shmem);
+}
+
/**
* drm_gem_shmem_pin - Pin backing pages for a shmem GEM object
* @shmem: shmem GEM object
@@ -303,10 +311,7 @@ void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem)
return;
dma_resv_lock(shmem->base.resv, NULL);
-
- if (refcount_dec_and_test(&shmem->pages_pin_count))
- drm_gem_shmem_put_pages_locked(shmem);
-
+ drm_gem_shmem_unpin_locked(shmem);
dma_resv_unlock(shmem->base.resv);
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_unpin);
@@ -344,7 +349,7 @@ int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
return 0;
}
- ret = drm_gem_shmem_get_pages_locked(shmem);
+ ret = drm_gem_shmem_pin_locked(shmem);
if (ret)
goto err_zero_use;
@@ -367,7 +372,7 @@ int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
err_put_pages:
if (!obj->import_attach)
- drm_gem_shmem_put_pages_locked(shmem);
+ drm_gem_shmem_unpin_locked(shmem);
err_zero_use:
shmem->vmap_use_count = 0;
@@ -404,7 +409,7 @@ void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem,
return;
vunmap(shmem->vaddr);
- drm_gem_shmem_put_pages_locked(shmem);
+ drm_gem_shmem_unpin_locked(shmem);
}
shmem->vaddr = NULL;
diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h
index bd3596e54abe..a6de11001048 100644
--- a/include/drm/drm_gem_shmem_helper.h
+++ b/include/drm/drm_gem_shmem_helper.h
@@ -124,7 +124,7 @@ int drm_gem_shmem_madvise_locked(struct drm_gem_shmem_object *shmem, int madv);
static inline bool drm_gem_shmem_is_purgeable(struct drm_gem_shmem_object *shmem)
{
return (shmem->madv > 0) &&
- !shmem->vmap_use_count && shmem->sgt &&
+ !refcount_read(&shmem->pages_pin_count) && shmem->sgt &&
!shmem->base.dma_buf && !shmem->base.import_attach;
}
--
2.41.0
On Mon, Oct 30, 2023 at 02:01:48AM +0300, Dmitry Osipenko wrote:
> The vmapped pages shall be pinned in memory and previously get/put_pages()
> were implicitly hard-pinning/unpinning the pages. This will no longer be
> the case with addition of memory shrinker because pages_use_count > 0 won't
> determine anymore whether pages are hard-pinned (they will be soft-pinned),
> while the new pages_pin_count will do the hard-pinning. Switch the
> vmap/vunmap() to use pin/unpin() functions in a preparation of addition
> of the memory shrinker support to drm-shmem.
>
> Reviewed-by: Boris Brezillon <[email protected]>
> Signed-off-by: Dmitry Osipenko <[email protected]>
The naming convention discussion aside, and once it's settled and fixed:
Acked-by: Maxime Ripard <[email protected]>
Maxime