[PATCH v2 2/3] drm/amdgpu: Reset the clear flag in buddy during resume
Arunpravin Paneer Selvam
Arunpravin.PaneerSelvam at amd.com
Tue Jul 1 19:08:21 UTC 2025
- Added a handler in DRM buddy manager to reset the cleared
flag for the blocks in the freelist.
- This is necessary because, upon resuming, the VRAM becomes
cluttered with BIOS data, yet the VRAM backend manager
believes that everything has been cleared.
v2:
- Add lock before accessing drm_buddy_clear_reset_blocks()(Matthew Auld)
- Force merge the two dirty blocks.(Matthew Auld)
- Add a new unit test case for this issue.(Matthew Auld)
- Having this function being able to flip the state either way would be
good. (Matthew Brost)
Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam at amd.com>
Suggested-by: Christian König <christian.koenig at amd.com>
Cc: stable at vger.kernel.org
Fixes: a68c7eaa7a8f ("drm/amdgpu: Enable clear page functionality")
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3812
---
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h | 1 +
drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 17 ++++
drivers/gpu/drm/drm_buddy.c | 90 +++++++++++++++++---
include/drm/drm_buddy.h | 2 +
5 files changed, 99 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index a59f194e3360..b89e46f29b51 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -5193,6 +5193,8 @@ int amdgpu_device_resume(struct drm_device *dev, bool notify_clients)
dev->dev->power.disable_depth--;
#endif
}
+
+ amdgpu_vram_mgr_clear_reset_blocks(adev);
adev->in_suspend = false;
if (amdgpu_acpi_smart_shift_update(dev, AMDGPU_SS_DEV_D0))
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
index 208b7d1d8a27..450e4bf093b7 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
@@ -154,6 +154,7 @@ int amdgpu_vram_mgr_reserve_range(struct amdgpu_vram_mgr *mgr,
uint64_t start, uint64_t size);
int amdgpu_vram_mgr_query_page_status(struct amdgpu_vram_mgr *mgr,
uint64_t start);
+void amdgpu_vram_mgr_clear_reset_blocks(struct amdgpu_device *adev);
bool amdgpu_res_cpu_visible(struct amdgpu_device *adev,
struct ttm_resource *res);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
index abdc52b0895a..665656fbc948 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
@@ -782,6 +782,23 @@ uint64_t amdgpu_vram_mgr_vis_usage(struct amdgpu_vram_mgr *mgr)
return atomic64_read(&mgr->vis_usage);
}
+/**
+ * amdgpu_vram_mgr_clear_reset_blocks - reset clear blocks
+ *
+ * @adev: amdgpu device pointer
+ *
+ * Reset the cleared drm buddy blocks.
+ */
+void amdgpu_vram_mgr_clear_reset_blocks(struct amdgpu_device *adev)
+{
+ struct amdgpu_vram_mgr *mgr = &adev->mman.vram_mgr;
+ struct drm_buddy *mm = &mgr->mm;
+
+ mutex_lock(&mgr->lock);
+ drm_buddy_reset_clear_state(mm, false);
+ mutex_unlock(&mgr->lock);
+}
+
/**
* amdgpu_vram_mgr_intersects - test each drm buddy block for intersection
*
diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
index a1e652b7631d..436f7e4ee202 100644
--- a/drivers/gpu/drm/drm_buddy.c
+++ b/drivers/gpu/drm/drm_buddy.c
@@ -12,6 +12,9 @@
#include <drm/drm_buddy.h>
+#define FORCE_MERGE BIT(0)
+#define RESET_CLEAR BIT(1)
+
static struct kmem_cache *slab_blocks;
static struct drm_buddy_block *drm_block_alloc(struct drm_buddy *mm,
@@ -60,6 +63,16 @@ static void list_insert_sorted(struct drm_buddy *mm,
__list_add(&block->link, node->link.prev, &node->link);
}
+static bool is_force_merge_enabled(unsigned int flags)
+{
+ return flags & FORCE_MERGE;
+}
+
+static bool is_reset_clear_enabled(unsigned int flags)
+{
+ return flags & RESET_CLEAR;
+}
+
static void clear_reset(struct drm_buddy_block *block)
{
block->header &= ~DRM_BUDDY_HEADER_CLEAR;
@@ -122,7 +135,7 @@ __get_buddy(struct drm_buddy_block *block)
static unsigned int __drm_buddy_free(struct drm_buddy *mm,
struct drm_buddy_block *block,
- bool force_merge)
+ unsigned int flags)
{
struct drm_buddy_block *parent;
unsigned int order;
@@ -135,7 +148,7 @@ static unsigned int __drm_buddy_free(struct drm_buddy *mm,
if (!drm_buddy_block_is_free(buddy))
break;
- if (!force_merge) {
+ if (!is_force_merge_enabled(flags)) {
/*
* Check the block and its buddy clear state and exit
* the loop if they both have the dissimilar state.
@@ -149,7 +162,9 @@ static unsigned int __drm_buddy_free(struct drm_buddy *mm,
}
list_del(&buddy->link);
- if (force_merge && drm_buddy_block_is_clear(buddy))
+ if (is_force_merge_enabled(flags) &&
+ !is_reset_clear_enabled(flags) &&
+ drm_buddy_block_is_clear(buddy))
mm->clear_avail -= drm_buddy_block_size(mm, buddy);
drm_block_free(mm, block);
@@ -167,7 +182,8 @@ static unsigned int __drm_buddy_free(struct drm_buddy *mm,
static int __force_merge(struct drm_buddy *mm,
u64 start,
u64 end,
- unsigned int min_order)
+ unsigned int min_order,
+ unsigned int flags)
{
unsigned int order;
int i;
@@ -178,6 +194,8 @@ static int __force_merge(struct drm_buddy *mm,
if (min_order > mm->max_order)
return -EINVAL;
+ flags |= FORCE_MERGE;
+
for (i = min_order - 1; i >= 0; i--) {
struct drm_buddy_block *block, *prev;
@@ -198,7 +216,8 @@ static int __force_merge(struct drm_buddy *mm,
if (!drm_buddy_block_is_free(buddy))
continue;
- WARN_ON(drm_buddy_block_is_clear(block) ==
+ WARN_ON(!is_reset_clear_enabled(flags) &&
+ drm_buddy_block_is_clear(block) ==
drm_buddy_block_is_clear(buddy));
/*
@@ -210,10 +229,11 @@ static int __force_merge(struct drm_buddy *mm,
prev = list_prev_entry(prev, link);
list_del(&block->link);
- if (drm_buddy_block_is_clear(block))
+ if (!is_reset_clear_enabled(flags) &&
+ drm_buddy_block_is_clear(block))
mm->clear_avail -= drm_buddy_block_size(mm, block);
- order = __drm_buddy_free(mm, block, true);
+ order = __drm_buddy_free(mm, block, flags);
if (order >= min_order)
return 0;
}
@@ -336,7 +356,7 @@ void drm_buddy_fini(struct drm_buddy *mm)
for (i = 0; i < mm->n_roots; ++i) {
order = ilog2(size) - ilog2(mm->chunk_size);
start = drm_buddy_block_offset(mm->roots[i]);
- __force_merge(mm, start, start + size, order);
+ __force_merge(mm, start, start + size, order, 0);
if (WARN_ON(!drm_buddy_block_is_free(mm->roots[i])))
kunit_fail_current_test("buddy_fini() root");
@@ -405,6 +425,50 @@ drm_get_buddy(struct drm_buddy_block *block)
}
EXPORT_SYMBOL(drm_get_buddy);
+/**
+ * drm_buddy_reset_clear_state - reset blocks clear state
+ *
+ * @mm: DRM buddy manager
+ * @is_clear: blocks clear state
+ *
+ * Reset the clear state based on @clear value for each block
+ * in the freelist.
+ */
+void drm_buddy_reset_clear_state(struct drm_buddy *mm, bool is_clear)
+{
+ u64 root_size, size, start;
+ unsigned int order;
+ int i;
+
+ for (i = 0; i <= mm->max_order; ++i) {
+ struct drm_buddy_block *block;
+
+ list_for_each_entry_reverse(block, &mm->free_list[i], link) {
+ if (is_clear != drm_buddy_block_is_clear(block)) {
+ if (is_clear) {
+ mark_cleared(block);
+ mm->clear_avail += drm_buddy_block_size(mm, block);
+ } else {
+ clear_reset(block);
+ mm->clear_avail -= drm_buddy_block_size(mm, block);
+ }
+ }
+ }
+ }
+
+ /* Force merge the two dirty or two cleared blocks */
+ size = mm->size;
+ for (i = 0; i < mm->n_roots; ++i) {
+ order = ilog2(size) - ilog2(mm->chunk_size);
+ start = drm_buddy_block_offset(mm->roots[i]);
+ __force_merge(mm, start, start + size, order, RESET_CLEAR);
+
+ root_size = mm->chunk_size << order;
+ size -= root_size;
+ }
+}
+EXPORT_SYMBOL(drm_buddy_reset_clear_state);
+
/**
* drm_buddy_free_block - free a block
*
@@ -419,7 +483,7 @@ void drm_buddy_free_block(struct drm_buddy *mm,
if (drm_buddy_block_is_clear(block))
mm->clear_avail += drm_buddy_block_size(mm, block);
- __drm_buddy_free(mm, block, false);
+ __drm_buddy_free(mm, block, 0);
}
EXPORT_SYMBOL(drm_buddy_free_block);
@@ -566,7 +630,7 @@ __alloc_range_bias(struct drm_buddy *mm,
if (buddy &&
(drm_buddy_block_is_free(block) &&
drm_buddy_block_is_free(buddy)))
- __drm_buddy_free(mm, block, false);
+ __drm_buddy_free(mm, block, 0);
return ERR_PTR(err);
}
@@ -684,7 +748,7 @@ alloc_from_freelist(struct drm_buddy *mm,
err_undo:
if (tmp != order)
- __drm_buddy_free(mm, block, false);
+ __drm_buddy_free(mm, block, 0);
return ERR_PTR(err);
}
@@ -770,7 +834,7 @@ static int __alloc_range(struct drm_buddy *mm,
if (buddy &&
(drm_buddy_block_is_free(block) &&
drm_buddy_block_is_free(buddy)))
- __drm_buddy_free(mm, block, false);
+ __drm_buddy_free(mm, block, 0);
err_free:
if (err == -ENOSPC && total_allocated_on_err) {
@@ -1051,7 +1115,7 @@ int drm_buddy_alloc_blocks(struct drm_buddy *mm,
if (order-- == min_order) {
/* Try allocation through force merge method */
if (mm->clear_avail &&
- !__force_merge(mm, start, end, min_order)) {
+ !__force_merge(mm, start, end, min_order, 0)) {
block = __drm_buddy_alloc_blocks(mm, start,
end,
min_order,
diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h
index 9689a7c5dd36..8b5273d4b2d1 100644
--- a/include/drm/drm_buddy.h
+++ b/include/drm/drm_buddy.h
@@ -160,6 +160,8 @@ int drm_buddy_block_trim(struct drm_buddy *mm,
u64 new_size,
struct list_head *blocks);
+void drm_buddy_reset_clear_state(struct drm_buddy *mm, bool is_clear);
+
void drm_buddy_free_block(struct drm_buddy *mm, struct drm_buddy_block *block);
void drm_buddy_free_list(struct drm_buddy *mm,
--
2.43.0
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