drm/shmem-helper: Add and use pages_pin_count

Add separate pages_pin_count for tracking of whether drm-shmem pages are
moveable or not. With the addition of memory shrinker support to drm-shmem,
the pages_use_count will no longer determine whether pages are hard-pinned
in memory, but whether pages exist and are soft-pinned (and could be swapped
out). The pages_pin_count > 1 will hard-pin pages in memory.

Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Suggested-by: Boris Brezillon <boris.brezillon@collabora.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.d>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250322212608.40511-8-dmitry.osipenko@collabora.com
This commit is contained in:
Dmitry Osipenko 2025-03-23 00:26:05 +03:00
parent eab1053807
commit d586b535f1
2 changed files with 26 additions and 1 deletions

View File

@ -177,6 +177,7 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
drm_gem_shmem_put_pages_locked(shmem);
drm_WARN_ON(obj->dev, shmem->pages_use_count);
drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_pin_count));
dma_resv_unlock(shmem->base.resv);
}
@ -257,7 +258,12 @@ int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem)
drm_WARN_ON(shmem->base.dev, drm_gem_is_imported(&shmem->base));
if (refcount_inc_not_zero(&shmem->pages_pin_count))
return 0;
ret = drm_gem_shmem_get_pages_locked(shmem);
if (!ret)
refcount_set(&shmem->pages_pin_count, 1);
return ret;
}
@ -267,7 +273,8 @@ void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem)
{
dma_resv_assert_held(shmem->base.resv);
drm_gem_shmem_put_pages_locked(shmem);
if (refcount_dec_and_test(&shmem->pages_pin_count))
drm_gem_shmem_put_pages_locked(shmem);
}
EXPORT_SYMBOL(drm_gem_shmem_unpin_locked);
@ -288,6 +295,9 @@ int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem)
drm_WARN_ON(obj->dev, drm_gem_is_imported(obj));
if (refcount_inc_not_zero(&shmem->pages_pin_count))
return 0;
ret = dma_resv_lock_interruptible(shmem->base.resv, NULL);
if (ret)
return ret;
@ -311,6 +321,9 @@ void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem)
drm_WARN_ON(obj->dev, drm_gem_is_imported(obj));
if (refcount_dec_not_one(&shmem->pages_pin_count))
return;
dma_resv_lock(shmem->base.resv, NULL);
drm_gem_shmem_unpin_locked(shmem);
dma_resv_unlock(shmem->base.resv);
@ -660,6 +673,7 @@ void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem,
if (drm_gem_is_imported(&shmem->base))
return;
drm_printf_indent(p, indent, "pages_pin_count=%u\n", refcount_read(&shmem->pages_pin_count));
drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count);
drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);
drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);

View File

@ -39,6 +39,17 @@ struct drm_gem_shmem_object {
*/
unsigned int pages_use_count;
/**
* @pages_pin_count:
*
* Reference count on the pinned pages table.
*
* Pages are hard-pinned and reside in memory if count
* greater than zero. Otherwise, when count is zero, the pages are
* allowed to be evicted and purged by memory shrinker.
*/
refcount_t pages_pin_count;
/**
* @madv: State for madvise
*