@@ -105,6 +105,65 @@ void ttm_tt_set_unpinned(const struct ttm_device *bdev, const struct ttm_tt *tt)
ttm_tt_mod_shrinkable_pages(tt->num_pages, 0);
}
+/**
+ * ttm_tt_set_dontneed() - Mark ttm_tt content as not needed.
+ * @bdev: The ttm device.
+ * @tt: The struct ttm_tt.
+ *
+ * Mark the ttm_tt content as not needed for the shrinker accounting.
+ * This also means that the content will not be backed up on shrinking,
+ * but rather freed immediately.
+ *
+ * Return: 0 if successful, -EALREADY if content was never present or
+ * already backed up and was purged by this call.
+ */
+int ttm_tt_set_dontneed(const struct ttm_device *bdev, struct ttm_tt *tt)
+{
+ if (ttm_tt_is_populated(tt)) {
+ if (!ttm_tt_purgeable(tt)) {
+ tt->page_flags |= TTM_TT_FLAG_DONTNEED;
+ if (ttm_tt_shrinkable(bdev, tt))
+ ttm_tt_mod_shrinkable_pages(-(long)tt->num_pages,
+ tt->num_pages);
+ }
+ return 0;
+ }
+
+ if (tt->swap_storage)
+ fput(tt->swap_storage);
+ tt->swap_storage = NULL;
+
+ return -EALREADY;
+}
+EXPORT_SYMBOL(ttm_tt_set_dontneed);
+
+/**
+ * ttm_tt_set_willneed() - Mark tt_tt content as needed.
+ * @bdev: The ttm device.
+ * @tt: The struct ttm_tt.
+ *
+ * Mark the ttm_tt content as needed and update the shrinker accounting
+ * accordingly.
+ *
+ * Return: 0 if successful, -EALREADY if content was never present or
+ * was already purged.
+ */
+int ttm_tt_set_willneed(const struct ttm_device *bdev, struct ttm_tt *tt)
+{
+ if (ttm_tt_is_populated(tt)) {
+ if (ttm_tt_purgeable(tt)) {
+ tt->page_flags &= ~TTM_TT_FLAG_DONTNEED;
+ if (ttm_tt_shrinkable(bdev, tt))
+ ttm_tt_mod_shrinkable_pages(tt->num_pages,
+ -(long)tt->num_pages);
+ }
+ return 0;
+ }
+
+ return -EALREADY;
+}
+EXPORT_SYMBOL(ttm_tt_set_willneed);
+
/*
* Allocates a ttm structure for the given BO.
*/
@@ -241,6 +241,9 @@ static inline bool ttm_tt_purgeable(struct ttm_tt *tt)
void ttm_tt_set_pinned(const struct ttm_device *bdev, const struct ttm_tt *tt);
void ttm_tt_set_unpinned(const struct ttm_device *bdev, const struct ttm_tt *tt);
+int ttm_tt_set_dontneed(const struct ttm_device *bdev, struct ttm_tt *tt);
+
+int ttm_tt_set_willneed(const struct ttm_device *bdev, struct ttm_tt *tt);
#if IS_ENABLED(CONFIG_AGP)
#include <linux/agp_backend.h>
In the absence of free swap space, a shrinker could still efficiently free memory the content of which is no longer needed, and graphics drivers typically has an interface to mark buffer object content as no longer needed. Add a possibility to propagate this to TTM, so that the shrinker accounting and shrinker actions can be updated accordingly. Moving forward, we will probably want this interface on the bo level and have bo move support for it, but for now we strictly only need it for the shrinker. Another option would be to have the drivers do the purgeable vs shrinkable accounting. This still leaves the responsibility to the driver to assign proper LRU priority to purgeable buffer object so that the shrinker finds those objects early during LRU traversal. Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> --- drivers/gpu/drm/ttm/ttm_tt.c | 59 ++++++++++++++++++++++++++++++++++++ include/drm/ttm/ttm_tt.h | 3 ++ 2 files changed, 62 insertions(+)