drm/ttm: Add sysfs interface to control pool allocator.

Sysfs interface allows user to configure pool allocator functionality and
change limits for the size of pool.

Signed-off-by: Pauli Nieminen <suokkos@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

2 files changed, 113 insertions, 2 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_memory.c b/drivers/gpu/drm/ttm/ttm_memory.c
index daff8a87977e..5e3f177323cb 100644
--- a/drivers/gpu/drm/ttm/ttm_memory.c
+++ b/drivers/gpu/drm/ttm/ttm_memory.c
@@ -393,7 +393,7 @@ int ttm_mem_global_init(struct ttm_mem_global *glob)
                        "Zone %7s: Available graphics memory: %llu kiB.\n",
                        zone->name, (unsigned long long) zone->max_mem >> 10);
         }
-        ttm_page_alloc_init(glob->zone_kernel->max_mem/(2*PAGE_SIZE));
+        ttm_page_alloc_init(glob, glob->zone_kernel->max_mem/(2*PAGE_SIZE));
         return 0;
 out_no_zone:
         ttm_mem_global_release(glob);
diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c b/drivers/gpu/drm/ttm/ttm_page_alloc.c
index 57799dba35e0..6ca9b27e33d5 100644
--- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
@@ -72,6 +72,12 @@ struct ttm_page_pool {
         unsigned long           nrefills;
 };
 
+/**
+ * Limits for the pool. They are handled without locks because only place where
+ * they may change is in sysfs store. They won't have immediate effect anyway
+ * so forcing serialiazation to access them is pointless.
+ */
+
 struct ttm_pool_opts {
         unsigned        alloc_size;
         unsigned        max_size;
@@ -94,6 +100,7 @@ struct ttm_pool_opts {
  * @pools: All pool objects in use.
  **/
 struct ttm_pool_manager {
+        struct kobject          kobj;
         struct shrinker         mm_shrink;
         atomic_t                page_alloc_inited;
         struct ttm_pool_opts    options;
@@ -109,6 +116,100 @@ struct ttm_pool_manager {
         };
 };
 
+static struct attribute ttm_page_pool_max = {
+        .name = "pool_max_size",
+        .mode = S_IRUGO | S_IWUSR
+};
+static struct attribute ttm_page_pool_small = {
+        .name = "pool_small_allocation",
+        .mode = S_IRUGO | S_IWUSR
+};
+static struct attribute ttm_page_pool_alloc_size = {
+        .name = "pool_allocation_size",
+        .mode = S_IRUGO | S_IWUSR
+};
+
+static struct attribute *ttm_pool_attrs[] = {
+        &ttm_page_pool_max,
+        &ttm_page_pool_small,
+        &ttm_page_pool_alloc_size,
+        NULL
+};
+
+static void ttm_pool_kobj_release(struct kobject *kobj)
+{
+        struct ttm_pool_manager *m =
+                container_of(kobj, struct ttm_pool_manager, kobj);
+        (void)m;
+}
+
+static ssize_t ttm_pool_store(struct kobject *kobj,
+                struct attribute *attr, const char *buffer, size_t size)
+{
+        struct ttm_pool_manager *m =
+                container_of(kobj, struct ttm_pool_manager, kobj);
+        int chars;
+        unsigned val;
+        chars = sscanf(buffer, "%u", &val);
+        if (chars == 0)
+                return size;
+
+        /* Convert kb to number of pages */
+        val = val / (PAGE_SIZE >> 10);
+
+        if (attr == &ttm_page_pool_max)
+                m->options.max_size = val;
+        else if (attr == &ttm_page_pool_small)
+                m->options.small = val;
+        else if (attr == &ttm_page_pool_alloc_size) {
+                if (val > NUM_PAGES_TO_ALLOC*8) {
+                        printk(KERN_ERR "[ttm] Setting allocation size to %lu "
+                                        "is not allowed. Recomended size is "
+                                        "%lu\n",
+                                        NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 7),
+                                        NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
+                        return size;
+                } else if (val > NUM_PAGES_TO_ALLOC) {
+                        printk(KERN_WARNING "[ttm] Setting allocation size to "
+                                        "larger than %lu is not recomended.\n",
+                                        NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
+                }
+                m->options.alloc_size = val;
+        }
+
+        return size;
+}
+
+static ssize_t ttm_pool_show(struct kobject *kobj,
+                struct attribute *attr, char *buffer)
+{
+        struct ttm_pool_manager *m =
+                container_of(kobj, struct ttm_pool_manager, kobj);
+        unsigned val = 0;
+
+        if (attr == &ttm_page_pool_max)
+                val = m->options.max_size;
+        else if (attr == &ttm_page_pool_small)
+                val = m->options.small;
+        else if (attr == &ttm_page_pool_alloc_size)
+                val = m->options.alloc_size;
+
+        val = val * (PAGE_SIZE >> 10);
+
+        return snprintf(buffer, PAGE_SIZE, "%u\n", val);
+}
+
+static const struct sysfs_ops ttm_pool_sysfs_ops = {
+        .show = &ttm_pool_show,
+        .store = &ttm_pool_store,
+};
+
+static struct kobj_type ttm_pool_kobj_type = {
+        .release = &ttm_pool_kobj_release,
+        .sysfs_ops = &ttm_pool_sysfs_ops,
+        .default_attrs = ttm_pool_attrs,
+};
+
 static struct ttm_pool_manager _manager = {
         .page_alloc_inited      = ATOMIC_INIT(0)
 };
@@ -669,8 +770,9 @@ static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, int flags,
         pool->name = name;
 }
 
-int ttm_page_alloc_init(unsigned max_pages)
+int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
 {
+        int ret;
         if (atomic_add_return(1, &_manager.page_alloc_inited) > 1)
                 return 0;
 
@@ -690,6 +792,13 @@ int ttm_page_alloc_init(unsigned max_pages)
         _manager.options.small = SMALL_ALLOCATION;
         _manager.options.alloc_size = NUM_PAGES_TO_ALLOC;
 
+        kobject_init(&_manager.kobj, &ttm_pool_kobj_type);
+        ret = kobject_add(&_manager.kobj, &glob->kobj, "pool");
+        if (unlikely(ret != 0)) {
+                kobject_put(&_manager.kobj);
+                return ret;
+        }
+
         ttm_pool_mm_shrink_init(&_manager);
 
         return 0;
@@ -707,6 +816,8 @@ void ttm_page_alloc_fini()
 
         for (i = 0; i < NUM_POOLS; ++i)
                 ttm_page_pool_free(&_manager.pools[i], FREE_ALL_PAGES);
+
+        kobject_put(&_manager.kobj);
 }
 
 int ttm_page_alloc_debugfs(struct seq_file *m, void *data)