drm/ttm: Add debugfs output entry to pool allocator.

ttm_page_alloc_debugfs can be registered to output the state
of pools.

Debugfs file will output number of pages freed from the pool,
number of pages in pool now and the lowes number of pages in
pool since previous shrink.
Signed-off-by: Pauli Nieminen <suokkos@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/ttm/ttm_page_alloc.c

@@ -34,6 +34,7 @@
 #include <linux/spinlock.h>
 #include <linux/highmem.h>
 #include <linux/mm_types.h>
+#include <linux/module.h>
 #include <linux/mm.h>
 
 #include <asm/atomic.h>
@@ -66,6 +67,9 @@ struct ttm_page_pool {
 	struct list_head	list;
 	int			gfp_flags;
 	unsigned		npages;
+	char			*name;
+	unsigned long		nfrees;
+	unsigned long		nrefills;
 };
 
 struct ttm_pool_opts {
@@ -190,6 +194,7 @@ static void ttm_pool_update_free_locked(struct ttm_page_pool *pool,
 		unsigned freed_pages)
 {
 	pool->npages -= freed_pages;
+	pool->nfrees += freed_pages;
 }
 
 /**
@@ -263,7 +268,6 @@ static int ttm_page_pool_free(struct ttm_page_pool *pool, unsigned nr_free)
 		}
 	}
 
-
 	/* remove range of pages from the pool */
 	if (freed_pages) {
 		__list_del(&p->lru, &pool->list);
@@ -490,6 +494,7 @@ static void ttm_page_pool_fill_locked(struct ttm_page_pool *pool,
 
 		if (!r) {
 			list_splice(&new_pages, &pool->list);
+			++pool->nrefills;
 			pool->npages += alloc_size;
 		} else {
 			printk(KERN_ERR "[ttm] Failed to fill pool (%p).", pool);
@@ -663,13 +668,15 @@ void ttm_put_pages(struct list_head *pages, unsigned page_count, int flags,
 		ttm_page_pool_free(pool, page_count);
 }
 
-static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, int flags)
+static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, int flags,
+		char *name)
 {
 	spin_lock_init(&pool->lock);
 	pool->fill_lock = false;
 	INIT_LIST_HEAD(&pool->list);
-	pool->npages = 0;
+	pool->npages = pool->nfrees = 0;
 	pool->gfp_flags = flags;
+	pool->name = name;
 }
 
 int ttm_page_alloc_init(unsigned max_pages)
@@ -679,13 +686,15 @@ int ttm_page_alloc_init(unsigned max_pages)
 
 	printk(KERN_INFO "[ttm] Initializing pool allocator.\n");
 
-	ttm_page_pool_init_locked(&_manager.wc_pool, GFP_HIGHUSER);
+	ttm_page_pool_init_locked(&_manager.wc_pool, GFP_HIGHUSER, "wc");
 
-	ttm_page_pool_init_locked(&_manager.uc_pool, GFP_HIGHUSER);
+	ttm_page_pool_init_locked(&_manager.uc_pool, GFP_HIGHUSER, "uc");
 
-	ttm_page_pool_init_locked(&_manager.wc_pool_dma32, GFP_USER | GFP_DMA32);
+	ttm_page_pool_init_locked(&_manager.wc_pool_dma32, GFP_USER | GFP_DMA32,
+			"wc dma");
 
-	ttm_page_pool_init_locked(&_manager.uc_pool_dma32, GFP_USER | GFP_DMA32);
+	ttm_page_pool_init_locked(&_manager.uc_pool_dma32, GFP_USER | GFP_DMA32,
+			"uc dma");
 
 	_manager.options.max_size = max_pages;
 	_manager.options.small = SMALL_ALLOCATION;
@@ -709,3 +718,25 @@ void ttm_page_alloc_fini()
 	for (i = 0; i < NUM_POOLS; ++i)
 		ttm_page_pool_free(&_manager.pools[i], FREE_ALL_PAGES);
 }
+
+int ttm_page_alloc_debugfs(struct seq_file *m, void *data)
+{
+	struct ttm_page_pool *p;
+	unsigned i;
+	char *h[] = {"pool", "refills", "pages freed", "size"};
+	if (atomic_read(&_manager.page_alloc_inited) == 0) {
+		seq_printf(m, "No pool allocator running.\n");
+		return 0;
+	}
+	seq_printf(m, "%6s %12s %13s %8s\n",
+			h[0], h[1], h[2], h[3]);
+	for (i = 0; i < NUM_POOLS; ++i) {
+		p = &_manager.pools[i];
+
+		seq_printf(m, "%6s %12ld %13ld %8d\n",
+				p->name, p->nrefills,
+				p->nfrees, p->npages);
+	}
+	return 0;
+}
+EXPORT_SYMBOL(ttm_page_alloc_debugfs);

include/drm/ttm/ttm_page_alloc.h

@@ -67,4 +67,8 @@ int ttm_page_alloc_init(unsigned max_pages);
  */
 void ttm_page_alloc_fini(void);
 
+/**
+ * Output the state of pools to debugfs file
+ */
+extern int ttm_page_alloc_debugfs(struct seq_file *m, void *data);
 #endif