Commit d586b535 authored by Dmitry Osipenko's avatar Dmitry Osipenko
Browse files

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: default avatarMaxime Ripard <mripard@kernel.org>
Reviewed-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
Suggested-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
Acked-by: default avatarThomas Zimmermann <tzimmermann@suse.d>
Signed-off-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250322212608.40511-8-dmitry.osipenko@collabora.com
parent eab10538

drivers/gpu/drm/drm_gem_shmem_helper.c

+15 −1
Original line number Diff line number Diff line
@@ -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;

}
@@ -267,6 +273,7 @@ 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);

}

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);

include/drm/drm_gem_shmem_helper.h

+11 −0
Original line number Diff line number Diff line
@@ -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

	 *