[PATCH 04/17] ttm/pool: port to list_lru. (v2)

[Dave Airlie <airlied@gmail.com>]

From: Dave Airlie <airlied@redhat.com>

This is an initial port of the TTM pools for
write combined and uncached pages to use the list_lru.

This makes the pool's more NUMA aware and avoids
needing separate NUMA pools (later commit enables this).

Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

---
v2: drop the pt->lock, lru list has it's own lock which is sufficent.
rearrange list isolates to fix bad locking orders.
---
 drivers/gpu/drm/ttm/tests/ttm_device_test.c |  2 +-
 drivers/gpu/drm/ttm/tests/ttm_pool_test.c   | 32 ++++----
 drivers/gpu/drm/ttm/ttm_pool.c              | 83 +++++++++++++--------
 include/drm/ttm/ttm_pool.h                  |  6 +-
 4 files changed, 72 insertions(+), 51 deletions(-)

diff --git a/drivers/gpu/drm/ttm/tests/ttm_device_test.c b/drivers/gpu/drm/ttm/tests/ttm_device_test.c
index 1621903818e5..1f207fd222bc 100644
--- a/drivers/gpu/drm/ttm/tests/ttm_device_test.c
+++ b/drivers/gpu/drm/ttm/tests/ttm_device_test.c
@@ -183,7 +183,7 @@ static void ttm_device_init_pools(struct kunit *test)
 
 				if (params->use_dma_alloc)
 					KUNIT_ASSERT_FALSE(test,
-							   list_empty(&pt.pages));
+							   !list_lru_count(&pt.pages));
 			}
 		}
 	}
diff --git a/drivers/gpu/drm/ttm/tests/ttm_pool_test.c b/drivers/gpu/drm/ttm/tests/ttm_pool_test.c
index 8ade53371f72..39234a3e98c4 100644
--- a/drivers/gpu/drm/ttm/tests/ttm_pool_test.c
+++ b/drivers/gpu/drm/ttm/tests/ttm_pool_test.c
@@ -248,7 +248,7 @@ static void ttm_pool_alloc_order_caching_match(struct kunit *test)
 	pool = ttm_pool_pre_populated(test, size, caching);
 
 	pt = &pool->caching[caching].orders[order];
-	KUNIT_ASSERT_FALSE(test, list_empty(&pt->pages));
+	KUNIT_ASSERT_FALSE(test, !list_lru_count(&pt->pages));
 
 	tt = ttm_tt_kunit_init(test, 0, caching, size);
 	KUNIT_ASSERT_NOT_NULL(test, tt);
@@ -256,7 +256,7 @@ static void ttm_pool_alloc_order_caching_match(struct kunit *test)
 	err = ttm_pool_alloc(pool, tt, &simple_ctx);
 	KUNIT_ASSERT_EQ(test, err, 0);
 
-	KUNIT_ASSERT_TRUE(test, list_empty(&pt->pages));
+	KUNIT_ASSERT_TRUE(test, !list_lru_count(&pt->pages));
 
 	ttm_pool_free(pool, tt);
 	ttm_tt_fini(tt);
@@ -282,8 +282,8 @@ static void ttm_pool_alloc_caching_mismatch(struct kunit *test)
 	tt = ttm_tt_kunit_init(test, 0, tt_caching, size);
 	KUNIT_ASSERT_NOT_NULL(test, tt);
 
-	KUNIT_ASSERT_FALSE(test, list_empty(&pt_pool->pages));
-	KUNIT_ASSERT_TRUE(test, list_empty(&pt_tt->pages));
+	KUNIT_ASSERT_FALSE(test, !list_lru_count(&pt_pool->pages));
+	KUNIT_ASSERT_TRUE(test, !list_lru_count(&pt_tt->pages));
 
 	err = ttm_pool_alloc(pool, tt, &simple_ctx);
 	KUNIT_ASSERT_EQ(test, err, 0);
@@ -291,8 +291,8 @@ static void ttm_pool_alloc_caching_mismatch(struct kunit *test)
 	ttm_pool_free(pool, tt);
 	ttm_tt_fini(tt);
 
-	KUNIT_ASSERT_FALSE(test, list_empty(&pt_pool->pages));
-	KUNIT_ASSERT_FALSE(test, list_empty(&pt_tt->pages));
+	KUNIT_ASSERT_FALSE(test, !list_lru_count(&pt_pool->pages));
+	KUNIT_ASSERT_FALSE(test, !list_lru_count(&pt_tt->pages));
 
 	ttm_pool_fini(pool);
 }
@@ -316,8 +316,8 @@ static void ttm_pool_alloc_order_mismatch(struct kunit *test)
 	tt = ttm_tt_kunit_init(test, 0, caching, snd_size);
 	KUNIT_ASSERT_NOT_NULL(test, tt);
 
-	KUNIT_ASSERT_FALSE(test, list_empty(&pt_pool->pages));
-	KUNIT_ASSERT_TRUE(test, list_empty(&pt_tt->pages));
+	KUNIT_ASSERT_FALSE(test, !list_lru_count(&pt_pool->pages));
+	KUNIT_ASSERT_TRUE(test, !list_lru_count(&pt_tt->pages));
 
 	err = ttm_pool_alloc(pool, tt, &simple_ctx);
 	KUNIT_ASSERT_EQ(test, err, 0);
@@ -325,8 +325,8 @@ static void ttm_pool_alloc_order_mismatch(struct kunit *test)
 	ttm_pool_free(pool, tt);
 	ttm_tt_fini(tt);
 
-	KUNIT_ASSERT_FALSE(test, list_empty(&pt_pool->pages));
-	KUNIT_ASSERT_FALSE(test, list_empty(&pt_tt->pages));
+	KUNIT_ASSERT_FALSE(test, !list_lru_count(&pt_pool->pages));
+	KUNIT_ASSERT_FALSE(test, !list_lru_count(&pt_tt->pages));
 
 	ttm_pool_fini(pool);
 }
@@ -352,12 +352,12 @@ static void ttm_pool_free_dma_alloc(struct kunit *test)
 	ttm_pool_alloc(pool, tt, &simple_ctx);
 
 	pt = &pool->caching[caching].orders[order];
-	KUNIT_ASSERT_TRUE(test, list_empty(&pt->pages));
+	KUNIT_ASSERT_TRUE(test, !list_lru_count(&pt->pages));
 
 	ttm_pool_free(pool, tt);
 	ttm_tt_fini(tt);
 
-	KUNIT_ASSERT_FALSE(test, list_empty(&pt->pages));
+	KUNIT_ASSERT_FALSE(test, !list_lru_count(&pt->pages));
 
 	ttm_pool_fini(pool);
 }
@@ -383,12 +383,12 @@ static void ttm_pool_free_no_dma_alloc(struct kunit *test)
 	ttm_pool_alloc(pool, tt, &simple_ctx);
 
 	pt = &pool->caching[caching].orders[order];
-	KUNIT_ASSERT_TRUE(test, list_is_singular(&pt->pages));
+	KUNIT_ASSERT_TRUE(test, list_lru_count(&pt->pages) == 1);
 
 	ttm_pool_free(pool, tt);
 	ttm_tt_fini(tt);
 
-	KUNIT_ASSERT_TRUE(test, list_is_singular(&pt->pages));
+	KUNIT_ASSERT_TRUE(test, list_lru_count(&pt->pages) == 1);
 
 	ttm_pool_fini(pool);
 }
@@ -404,11 +404,11 @@ static void ttm_pool_fini_basic(struct kunit *test)
 	pool = ttm_pool_pre_populated(test, size, caching);
 	pt = &pool->caching[caching].orders[order];
 
-	KUNIT_ASSERT_FALSE(test, list_empty(&pt->pages));
+	KUNIT_ASSERT_FALSE(test, !list_lru_count(&pt->pages));
 
 	ttm_pool_fini(pool);
 
-	KUNIT_ASSERT_TRUE(test, list_empty(&pt->pages));
+	KUNIT_ASSERT_TRUE(test, !list_lru_count(&pt->pages));
 }
 
 static struct kunit_case ttm_pool_test_cases[] = {
diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c
index 11a5777b4a85..4372f0cc4a57 100644
--- a/drivers/gpu/drm/ttm/ttm_pool.c
+++ b/drivers/gpu/drm/ttm/ttm_pool.c
@@ -291,7 +291,7 @@ static void ttm_pool_unmap(struct ttm_pool *pool, dma_addr_t dma_addr,
 static void ttm_pool_type_give(struct ttm_pool_type *pt, struct page *p)
 {
 	unsigned int i, num_pages = 1 << pt->order;
-	int nid = ttm_pool_nid(pt->pool);
+	int nid = page_to_nid(p);
 
 	for (i = 0; i < num_pages; ++i) {
 		if (PageHighMem(p))
@@ -300,31 +300,41 @@ static void ttm_pool_type_give(struct ttm_pool_type *pt, struct page *p)
 			clear_page(page_address(p + i));
 	}
 
-	spin_lock(&pt->lock);
-	list_add(&p->lru, &pt->pages);
-	spin_unlock(&pt->lock);
+	INIT_LIST_HEAD(&p->lru);
+	rcu_read_lock();
+	list_lru_add(&pt->pages, &p->lru, nid, NULL);
+	rcu_read_unlock();
 	atomic_long_add(1 << pt->order, &allocated_pages);
 
 	mod_node_page_state(NODE_DATA(nid), NR_GPU_ACTIVE, -num_pages);
 	mod_node_page_state(NODE_DATA(nid), NR_GPU_RECLAIM, num_pages);
 }
 
+static enum lru_status take_one_from_lru(struct list_head *item,
+					 struct list_lru_one *list,
+					 void *cb_arg)
+{
+	struct page **out_page = cb_arg;
+	struct page *p = container_of(item, struct page, lru);
+	list_lru_isolate(list, item);
+
+	*out_page = p;
+	return LRU_REMOVED;
+}
+
 /* Take pages from a specific pool_type, return NULL when nothing available */
-static struct page *ttm_pool_type_take(struct ttm_pool_type *pt)
+static struct page *ttm_pool_type_take(struct ttm_pool_type *pt, int nid)
 {
-	struct page *p;
-	int nid = ttm_pool_nid(pt->pool);
+	int ret;
+	struct page *p = NULL;
+	unsigned long nr_to_walk = 1;
 
-	spin_lock(&pt->lock);
-	p = list_first_entry_or_null(&pt->pages, typeof(*p), lru);
-	if (p) {
+	ret = list_lru_walk_node(&pt->pages, nid, take_one_from_lru, (void *)&p, &nr_to_walk);
+	if (ret == 1 && p) {
 		atomic_long_sub(1 << pt->order, &allocated_pages);
 		mod_node_page_state(NODE_DATA(nid), NR_GPU_ACTIVE, (1 << pt->order));
 		mod_node_page_state(NODE_DATA(nid), NR_GPU_RECLAIM, -(1 << pt->order));
-		list_del(&p->lru);
 	}
-	spin_unlock(&pt->lock);
-
 	return p;
 }
 
@@ -335,25 +345,47 @@ static void ttm_pool_type_init(struct ttm_pool_type *pt, struct ttm_pool *pool,
 	pt->pool = pool;
 	pt->caching = caching;
 	pt->order = order;
-	spin_lock_init(&pt->lock);
-	INIT_LIST_HEAD(&pt->pages);
+	list_lru_init(&pt->pages);
 
 	spin_lock(&shrinker_lock);
 	list_add_tail(&pt->shrinker_list, &shrinker_list);
 	spin_unlock(&shrinker_lock);
 }
 
+static enum lru_status pool_move_to_dispose_list(struct list_head *item,
+						 struct list_lru_one *list,
+						 void *cb_arg)
+{
+	struct list_head *dispose = cb_arg;
+
+	list_lru_isolate_move(list, item, dispose);
+
+	return LRU_REMOVED;
+}
+
+static void ttm_pool_dispose_list(struct ttm_pool_type *pt,
+				  struct list_head *dispose)
+{
+	while (!list_empty(dispose)) {
+		struct page *p;
+		p = list_first_entry(dispose, struct page, lru);
+		list_del_init(&p->lru);
+		atomic_long_sub(1 << pt->order, &allocated_pages);
+		ttm_pool_free_page(pt->pool, pt->caching, pt->order, p, true);
+	}
+}
+
 /* Remove a pool_type from the global shrinker list and free all pages */
 static void ttm_pool_type_fini(struct ttm_pool_type *pt)
 {
-	struct page *p;
+	LIST_HEAD(dispose);
 
 	spin_lock(&shrinker_lock);
 	list_del(&pt->shrinker_list);
 	spin_unlock(&shrinker_lock);
 
-	while ((p = ttm_pool_type_take(pt)))
-		ttm_pool_free_page(pt->pool, pt->caching, pt->order, p, true);
+	list_lru_walk(&pt->pages, pool_move_to_dispose_list, &dispose, LONG_MAX);
+	ttm_pool_dispose_list(pt, &dispose);
 }
 
 /* Return the pool_type to use for the given caching and order */
@@ -403,7 +435,7 @@ static unsigned int ttm_pool_shrink(void)
 	list_move_tail(&pt->shrinker_list, &shrinker_list);
 	spin_unlock(&shrinker_lock);
 
-	p = ttm_pool_type_take(pt);
+	p = ttm_pool_type_take(pt, ttm_pool_nid(pt->pool));
 	if (p) {
 		ttm_pool_free_page(pt->pool, pt->caching, pt->order, p, true);
 		num_pages = 1 << pt->order;
@@ -757,7 +789,7 @@ static int __ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
 		p = NULL;
 		pt = ttm_pool_select_type(pool, page_caching, order);
 		if (pt && allow_pools)
-			p = ttm_pool_type_take(pt);
+			p = ttm_pool_type_take(pt, ttm_pool_nid(pool));
 		/*
 		 * If that fails or previously failed, allocate from system.
 		 * Note that this also disallows additional pool allocations using
@@ -1186,16 +1218,7 @@ static unsigned long ttm_pool_shrinker_count(struct shrinker *shrink,
 /* Count the number of pages available in a pool_type */
 static unsigned int ttm_pool_type_count(struct ttm_pool_type *pt)
 {
-	unsigned int count = 0;
-	struct page *p;
-
-	spin_lock(&pt->lock);
-	/* Only used for debugfs, the overhead doesn't matter */
-	list_for_each_entry(p, &pt->pages, lru)
-		++count;
-	spin_unlock(&pt->lock);
-
-	return count;
+	return list_lru_count(&pt->pages);
 }
 
 /* Print a nice header for the order */
diff --git a/include/drm/ttm/ttm_pool.h b/include/drm/ttm/ttm_pool.h
index 54cd34a6e4c0..df56527c4853 100644
--- a/include/drm/ttm/ttm_pool.h
+++ b/include/drm/ttm/ttm_pool.h
@@ -45,8 +45,7 @@ struct ttm_tt;
  * @order: the allocation order our pages have
  * @caching: the caching type our pages have
  * @shrinker_list: our place on the global shrinker list
- * @lock: protection of the page list
- * @pages: the list of pages in the pool
+ * @pages: the lru_list of pages in the pool
  */
 struct ttm_pool_type {
 	struct ttm_pool *pool;
@@ -55,8 +54,7 @@ struct ttm_pool_type {
 
 	struct list_head shrinker_list;
 
-	spinlock_t lock;
-	struct list_head pages;
+	struct list_lru pages;
 };
 
 /**
-- 
2.49.0