[PATCH v6 04/12] drm/ttm, drm/amdgpu, drm/xe: Consider hitch moves within bulk sublist moves
Thomas Hellström
thomas.hellstrom at linux.intel.com
Wed Jul 3 15:38:05 UTC 2024
To address the problem with hitches moving when bulk move
sublists are lru-bumped, register the list cursors with the
ttm_lru_bulk_move structure when traversing its list, and
when lru-bumping the list, move the cursor hitch to the tail.
This also means it's mandatory for drivers to call
ttm_lru_bulk_move_init() and ttm_lru_bulk_move_fini() when
initializing and finalizing the bulk move structure, so add
those calls to the amdgpu- and xe driver.
Compared to v1 this is slightly more code but less fragile
and hopefully easier to understand.
Changes in previous series:
- Completely rework the functionality
- Avoid a NULL pointer dereference assigning manager->mem_type
- Remove some leftover code causing build problems
v2:
- For hitch bulk tail moves, store the mem_type in the cursor
instead of with the manager.
v3:
- Remove leftover mem_type member from change in v2.
v6:
- Add some lockdep asserts (Matthew Brost)
- Avoid NULL pointer dereference (Matthew Brost)
- No need to check bo->resource before dereferencing
bo->bulk_move (Matthew Brost)
Cc: Christian König <christian.koenig at amd.com>
Cc: Somalapuram Amaranath <Amaranath.Somalapuram at amd.com>
Cc: Matthew Brost <matthew.brost at intel.com>
Cc: <dri-devel at lists.freedesktop.org>
Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 4 ++
drivers/gpu/drm/ttm/ttm_resource.c | 92 ++++++++++++++++++++++++++
drivers/gpu/drm/xe/xe_vm.c | 4 ++
include/drm/ttm/ttm_resource.h | 56 ++++++++++------
4 files changed, 135 insertions(+), 21 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 3abfa66d72a2..97743993d711 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -2420,6 +2420,8 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm,
if (r)
return r;
+ ttm_lru_bulk_move_init(&vm->lru_bulk_move);
+
vm->is_compute_context = false;
vm->use_cpu_for_update = !!(adev->vm_manager.vm_update_mode &
@@ -2484,6 +2486,7 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm,
error_free_delayed:
dma_fence_put(vm->last_tlb_flush);
dma_fence_put(vm->last_unlocked);
+ ttm_lru_bulk_move_fini(&adev->mman.bdev, &vm->lru_bulk_move);
amdgpu_vm_fini_entities(vm);
return r;
@@ -2640,6 +2643,7 @@ void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
}
}
+ ttm_lru_bulk_move_fini(&adev->mman.bdev, &vm->lru_bulk_move);
}
/**
diff --git a/drivers/gpu/drm/ttm/ttm_resource.c b/drivers/gpu/drm/ttm/ttm_resource.c
index 9c8b6499edfb..b6a2daac5518 100644
--- a/drivers/gpu/drm/ttm/ttm_resource.c
+++ b/drivers/gpu/drm/ttm/ttm_resource.c
@@ -33,6 +33,53 @@
#include <drm/drm_util.h>
+/* Detach the cursor from the bulk move list*/
+static void
+ttm_resource_cursor_clear_bulk(struct ttm_resource_cursor *cursor)
+{
+ lockdep_assert_held(&cursor->man->bdev->lru_lock);
+
+ cursor->bulk = NULL;
+ list_del_init(&cursor->bulk_link);
+}
+
+/* Move the cursor to the end of the bulk move list it's in */
+static void ttm_resource_cursor_move_bulk_tail(struct ttm_lru_bulk_move *bulk,
+ struct ttm_resource_cursor *cursor)
+{
+ struct ttm_lru_bulk_move_pos *pos;
+
+ lockdep_assert_held(&cursor->man->bdev->lru_lock);
+
+ if (WARN_ON_ONCE(bulk != cursor->bulk)) {
+ list_del_init(&cursor->bulk_link);
+ return;
+ }
+
+ pos = &bulk->pos[cursor->mem_type][cursor->priority];
+ if (pos->last)
+ list_move(&cursor->hitch.link, &pos->last->lru.link);
+ ttm_resource_cursor_clear_bulk(cursor);
+}
+
+/* Move all cursors attached to a bulk move to its end */
+static void ttm_bulk_move_adjust_cursors(struct ttm_lru_bulk_move *bulk)
+{
+ struct ttm_resource_cursor *cursor, *next;
+
+ list_for_each_entry_safe(cursor, next, &bulk->cursor_list, bulk_link)
+ ttm_resource_cursor_move_bulk_tail(bulk, cursor);
+}
+
+/* Remove a cursor from an empty bulk move list */
+static void ttm_bulk_move_drop_cursors(struct ttm_lru_bulk_move *bulk)
+{
+ struct ttm_resource_cursor *cursor, *next;
+
+ list_for_each_entry_safe(cursor, next, &bulk->cursor_list, bulk_link)
+ ttm_resource_cursor_clear_bulk(cursor);
+}
+
/**
* ttm_resource_cursor_fini_locked() - Finalize the LRU list cursor usage
* @cursor: The struct ttm_resource_cursor to finalize.
@@ -45,6 +92,7 @@ void ttm_resource_cursor_fini_locked(struct ttm_resource_cursor *cursor)
{
lockdep_assert_held(&cursor->man->bdev->lru_lock);
list_del_init(&cursor->hitch.link);
+ ttm_resource_cursor_clear_bulk(cursor);
}
/**
@@ -73,9 +121,27 @@ void ttm_resource_cursor_fini(struct ttm_resource_cursor *cursor)
void ttm_lru_bulk_move_init(struct ttm_lru_bulk_move *bulk)
{
memset(bulk, 0, sizeof(*bulk));
+ INIT_LIST_HEAD(&bulk->cursor_list);
}
EXPORT_SYMBOL(ttm_lru_bulk_move_init);
+/**
+ * ttm_lru_bulk_move_fini - finalize a bulk move structure
+ * @bdev: The struct ttm_device
+ * @bulk: the structure to finalize
+ *
+ * Sanity checks that bulk moves don't have any
+ * resources left and hence no cursors attached.
+ */
+void ttm_lru_bulk_move_fini(struct ttm_device *bdev,
+ struct ttm_lru_bulk_move *bulk)
+{
+ spin_lock(&bdev->lru_lock);
+ ttm_bulk_move_drop_cursors(bulk);
+ spin_unlock(&bdev->lru_lock);
+}
+EXPORT_SYMBOL(ttm_lru_bulk_move_fini);
+
/**
* ttm_lru_bulk_move_tail - bulk move range of resources to the LRU tail.
*
@@ -88,6 +154,7 @@ void ttm_lru_bulk_move_tail(struct ttm_lru_bulk_move *bulk)
{
unsigned i, j;
+ ttm_bulk_move_adjust_cursors(bulk);
for (i = 0; i < TTM_NUM_MEM_TYPES; ++i) {
for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
struct ttm_lru_bulk_move_pos *pos = &bulk->pos[i][j];
@@ -515,6 +582,28 @@ void ttm_resource_manager_debug(struct ttm_resource_manager *man,
}
EXPORT_SYMBOL(ttm_resource_manager_debug);
+static void
+ttm_resource_cursor_check_bulk(struct ttm_resource_cursor *cursor,
+ struct ttm_lru_item *next_lru)
+{
+ struct ttm_resource *next = ttm_lru_item_to_res(next_lru);
+ struct ttm_lru_bulk_move *bulk = NULL;
+ struct ttm_buffer_object *bo = next->bo;
+
+ lockdep_assert_held(&cursor->man->bdev->lru_lock);
+ bulk = bo->bulk_move;
+
+ if (cursor->bulk != bulk) {
+ if (bulk) {
+ list_move_tail(&cursor->bulk_link, &bulk->cursor_list);
+ cursor->mem_type = next->mem_type;
+ } else {
+ list_del_init(&cursor->bulk_link);
+ }
+ cursor->bulk = bulk;
+ }
+}
+
/**
* ttm_resource_manager_first() - Start iterating over the resources
* of a resource manager
@@ -535,6 +624,7 @@ ttm_resource_manager_first(struct ttm_resource_manager *man,
cursor->priority = 0;
cursor->man = man;
ttm_lru_item_init(&cursor->hitch, TTM_LRU_HITCH);
+ INIT_LIST_HEAD(&cursor->bulk_link);
list_add(&cursor->hitch.link, &man->lru[cursor->priority]);
return ttm_resource_manager_next(cursor);
@@ -559,6 +649,7 @@ ttm_resource_manager_next(struct ttm_resource_cursor *cursor)
lru = &cursor->hitch;
list_for_each_entry_continue(lru, &man->lru[cursor->priority], link) {
if (ttm_lru_item_is_res(lru)) {
+ ttm_resource_cursor_check_bulk(cursor, lru);
list_move(&cursor->hitch.link, &lru->link);
return ttm_lru_item_to_res(lru);
}
@@ -568,6 +659,7 @@ ttm_resource_manager_next(struct ttm_resource_cursor *cursor)
break;
list_move(&cursor->hitch.link, &man->lru[cursor->priority]);
+ ttm_resource_cursor_clear_bulk(cursor);
}
ttm_resource_cursor_fini_locked(cursor);
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 5b166fa03684..0c7e327bc9a2 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -1335,6 +1335,8 @@ struct xe_vm *xe_vm_create(struct xe_device *xe, u32 flags)
INIT_WORK(&vm->destroy_work, vm_destroy_work_func);
+ ttm_lru_bulk_move_init(&vm->lru_bulk_move);
+
INIT_LIST_HEAD(&vm->preempt.exec_queues);
vm->preempt.min_run_period_ms = 10; /* FIXME: Wire up to uAPI */
@@ -1458,6 +1460,7 @@ struct xe_vm *xe_vm_create(struct xe_device *xe, u32 flags)
mutex_destroy(&vm->snap_mutex);
for_each_tile(tile, xe, id)
xe_range_fence_tree_fini(&vm->rftree[id]);
+ ttm_lru_bulk_move_fini(&xe->ttm, &vm->lru_bulk_move);
kfree(vm);
if (flags & XE_VM_FLAG_LR_MODE)
xe_pm_runtime_put(xe);
@@ -1601,6 +1604,7 @@ static void vm_destroy_work_func(struct work_struct *w)
XE_WARN_ON(vm->pt_root[id]);
trace_xe_vm_free(vm);
+ ttm_lru_bulk_move_fini(&xe->ttm, &vm->lru_bulk_move);
kfree(vm);
}
diff --git a/include/drm/ttm/ttm_resource.h b/include/drm/ttm/ttm_resource.h
index 8fac781f641e..571abb4861a6 100644
--- a/include/drm/ttm/ttm_resource.h
+++ b/include/drm/ttm/ttm_resource.h
@@ -269,26 +269,6 @@ ttm_lru_item_to_res(struct ttm_lru_item *item)
return container_of(item, struct ttm_resource, lru);
}
-/**
- * struct ttm_resource_cursor
- *
- * @man: The resource manager currently being iterated over.
- * @hitch: A hitch list node inserted before the next resource
- * to iterate over.
- * @priority: the current priority
- *
- * Cursor to iterate over the resources in a manager.
- */
-struct ttm_resource_cursor {
- struct ttm_resource_manager *man;
- struct ttm_lru_item hitch;
- unsigned int priority;
-};
-
-void ttm_resource_cursor_fini_locked(struct ttm_resource_cursor *cursor);
-
-void ttm_resource_cursor_fini(struct ttm_resource_cursor *cursor);
-
/**
* struct ttm_lru_bulk_move_pos
*
@@ -304,8 +284,9 @@ struct ttm_lru_bulk_move_pos {
/**
* struct ttm_lru_bulk_move
- *
* @pos: first/last lru entry for resources in the each domain/priority
+ * @cursor_list: The list of cursors currently traversing any of
+ * the sublists of @pos. Protected by the ttm device's lru_lock.
*
* Container for the current bulk move state. Should be used with
* ttm_lru_bulk_move_init() and ttm_bo_set_bulk_move().
@@ -315,8 +296,39 @@ struct ttm_lru_bulk_move_pos {
*/
struct ttm_lru_bulk_move {
struct ttm_lru_bulk_move_pos pos[TTM_NUM_MEM_TYPES][TTM_MAX_BO_PRIORITY];
+ struct list_head cursor_list;
};
+/**
+ * struct ttm_resource_cursor
+ * @man: The resource manager currently being iterated over
+ * @hitch: A hitch list node inserted before the next resource
+ * to iterate over.
+ * @bulk_link: A list link for the list of cursors traversing the
+ * bulk sublist of @bulk. Protected by the ttm device's lru_lock.
+ * @bulk: Pointer to struct ttm_lru_bulk_move whose subrange @hitch is
+ * inserted to. NULL if none. Never dereference this pointer since
+ * the struct ttm_lru_bulk_move object pointed to might have been
+ * freed. The pointer is only for comparison.
+ * @mem_type: The memory type of the LRU list being traversed.
+ * This field is valid iff @bulk != NULL.
+ * @priority: the current priority
+ *
+ * Cursor to iterate over the resources in a manager.
+ */
+struct ttm_resource_cursor {
+ struct ttm_resource_manager *man;
+ struct ttm_lru_item hitch;
+ struct list_head bulk_link;
+ struct ttm_lru_bulk_move *bulk;
+ unsigned int mem_type;
+ unsigned int priority;
+};
+
+void ttm_resource_cursor_fini_locked(struct ttm_resource_cursor *cursor);
+
+void ttm_resource_cursor_fini(struct ttm_resource_cursor *cursor);
+
/**
* struct ttm_kmap_iter_iomap - Specialization for a struct io_mapping +
* struct sg_table backed struct ttm_resource.
@@ -405,6 +417,8 @@ ttm_resource_manager_cleanup(struct ttm_resource_manager *man)
void ttm_lru_bulk_move_init(struct ttm_lru_bulk_move *bulk);
void ttm_lru_bulk_move_tail(struct ttm_lru_bulk_move *bulk);
+void ttm_lru_bulk_move_fini(struct ttm_device *bdev,
+ struct ttm_lru_bulk_move *bulk);
void ttm_resource_add_bulk_move(struct ttm_resource *res,
struct ttm_buffer_object *bo);
--
2.44.0
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