ANDROID: staging: android: ion: Expose total heap and pool sizes via sysfs

Add sysfs attributes to track ion total heap and pool memory allocations.
The following sysfs attributes are added:

/sys/kernel/ion/total_heaps_kb
/sys/kernel/ion/total_pools_kb

Bug: 138148041
Bug: 154238995
Test: adb shell cat /sys/kernel/ion/*
Change-Id: If92770dc3389af865c619525f04d3ba0e013b244
Signed-off-by: Suren Baghdasaryan <surenb@google.com>

Documentation/ABI/testing/sysfs-kernel-ion

@@ -0,0 +1,27 @@
+What:		/sys/kernel/ion
+Date:		Dec 2019
+KernelVersion:	4.14.158
+Contact:	Suren Baghdasaryan <surenb@google.com>,
+		Sandeep Patil <sspatil@google.com>
+Description:
+		The /sys/kernel/ion directory contains a snapshot of the
+		internal state of ION memory heaps and pools.
+Users:		kernel memory tuning tools
+
+What:		/sys/kernel/ion/total_heaps_kb
+Date:		Dec 2019
+KernelVersion:	4.14.158
+Contact:	Suren Baghdasaryan <surenb@google.com>,
+		Sandeep Patil <sspatil@google.com>
+Description:
+		The total_heaps_kb file is read-only and specifies how much
+		memory in Kb is allocated to ION heaps.
+
+What:		/sys/kernel/ion/total_pools_kb
+Date:		Dec 2019
+KernelVersion:	4.14.158
+Contact:	Suren Baghdasaryan <surenb@google.com>,
+		Sandeep Patil <sspatil@google.com>
+Description:
+		The total_pools_kb file is read-only and specifies how much
+		memory in Kb is allocated to ION pools.

drivers/staging/android/ion/heaps/ion_page_pool.c

@@ -97,6 +97,17 @@ static int ion_page_pool_total(struct ion_page_pool *pool, bool high)
 	return count << pool->order;
 }
 
+int ion_page_pool_nr_pages(struct ion_page_pool *pool)
+{
+	int nr_total_pages;
+
+	mutex_lock(&pool->mutex);
+	nr_total_pages = ion_page_pool_total(pool, true);
+	mutex_unlock(&pool->mutex);
+
+	return nr_total_pages;
+}
+
 int ion_page_pool_shrink(struct ion_page_pool *pool, gfp_t gfp_mask,
 			 int nr_to_scan)
 {

drivers/staging/android/ion/heaps/ion_page_pool.h

@@ -53,6 +53,7 @@ struct ion_page_pool *ion_page_pool_create(gfp_t gfp_mask, unsigned int order);
 void ion_page_pool_destroy(struct ion_page_pool *pool);
 struct page *ion_page_pool_alloc(struct ion_page_pool *pool);
 void ion_page_pool_free(struct ion_page_pool *pool, struct page *page);
+int ion_page_pool_nr_pages(struct ion_page_pool *pool);
 
 /** ion_page_pool_shrink - shrinks the size of the memory cached in the pool
  * @pool:		the pool

drivers/staging/android/ion/heaps/ion_system_heap.c

@@ -208,6 +208,19 @@ static int ion_system_heap_shrink(struct ion_heap *heap, gfp_t gfp_mask,
 	return nr_total;
 }
 
+static long ion_system_get_pool_size(struct ion_heap *heap)
+{
+	struct ion_system_heap *sys_heap;
+	long total_pages = 0;
+	int i;
+
+	sys_heap = container_of(heap, struct ion_system_heap, heap);
+	for (i = 0; i < NUM_ORDERS; i++)
+		total_pages += ion_page_pool_nr_pages(sys_heap->pools[i]);
+
+	return total_pages;
+}
+
 static void ion_system_heap_destroy_pools(struct ion_page_pool **pools)
 {
 	int i;
@@ -245,6 +258,7 @@ static struct ion_heap_ops system_heap_ops = {
 	.allocate = ion_system_heap_allocate,
 	.free = ion_system_heap_free,
 	.shrink = ion_system_heap_shrink,
+	.get_pool_size = ion_system_get_pool_size,
 };
 
 static struct ion_system_heap system_heap = {

drivers/staging/android/ion/ion.c

@@ -424,6 +424,63 @@ void ion_device_remove_heap(struct ion_heap *heap)
 }
 EXPORT_SYMBOL_GPL(ion_device_remove_heap);
 
+static ssize_t
+total_heaps_kb_show(struct kobject *kobj, struct kobj_attribute *attr,
+		    char *buf)
+{
+	return sprintf(buf, "%llu\n",
+		       div_u64(ion_get_total_heap_bytes(), 1024));
+}
+
+static ssize_t
+total_pools_kb_show(struct kobject *kobj, struct kobj_attribute *attr,
+		    char *buf)
+{
+	struct ion_device *dev = internal_dev;
+	struct ion_heap *heap;
+	u64 total_pages = 0;
+
+	down_read(&dev->lock);
+	plist_for_each_entry(heap, &dev->heaps, node)
+		if (heap->ops->get_pool_size)
+			total_pages += heap->ops->get_pool_size(heap);
+	up_read(&dev->lock);
+
+	return sprintf(buf, "%llu\n", total_pages * (PAGE_SIZE / 1024));
+}
+
+static struct kobj_attribute total_heaps_kb_attr =
+	__ATTR_RO(total_heaps_kb);
+
+static struct kobj_attribute total_pools_kb_attr =
+	__ATTR_RO(total_pools_kb);
+
+static struct attribute *ion_device_attrs[] = {
+	&total_heaps_kb_attr.attr,
+	&total_pools_kb_attr.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(ion_device);
+
+static int ion_init_sysfs(void)
+{
+	struct kobject *ion_kobj;
+	int ret;
+
+	ion_kobj = kobject_create_and_add("ion", kernel_kobj);
+	if (!ion_kobj)
+		return -ENOMEM;
+
+	ret = sysfs_create_groups(ion_kobj, ion_device_groups);
+	if (ret) {
+		kobject_put(ion_kobj);
+		return ret;
+	}
+
+	return 0;
+}
+
 static int ion_device_create(void)
 {
 	struct ion_device *idev;
@@ -440,8 +497,13 @@ static int ion_device_create(void)
 	ret = misc_register(&idev->dev);
 	if (ret) {
 		pr_err("ion: failed to register misc device.\n");
-		kfree(idev);
-		return ret;
+		goto err_reg;
+	}
+
+	ret = ion_init_sysfs();
+	if (ret) {
+		pr_err("ion: failed to add sysfs attributes.\n");
+		goto err_sysfs;
 	}
 
 	idev->debug_root = debugfs_create_dir("ion", NULL);
@@ -449,5 +511,11 @@ static int ion_device_create(void)
 	plist_head_init(&idev->heaps);
 	internal_dev = idev;
 	return 0;
+
+err_sysfs:
+	misc_deregister(&idev->dev);
+err_reg:
+	kfree(idev);
+	return ret;
 }
 subsys_initcall(ion_device_create);

drivers/staging/android/ion/ion_buffer.c

@@ -13,6 +13,8 @@
 
 #include "ion_private.h"
 
+static atomic_long_t total_heap_bytes;
+
 /* this function should only be called while dev->lock is held */
 static struct ion_buffer *ion_buffer_create(struct ion_heap *heap,
 					    struct ion_device *dev,
@@ -65,6 +67,7 @@ static struct ion_buffer *ion_buffer_create(struct ion_heap *heap,
 
 	INIT_LIST_HEAD(&buffer->attachments);
 	mutex_init(&buffer->lock);
+	atomic_long_add(len, &total_heap_bytes);
 	return buffer;
 
 err1:
@@ -215,6 +218,7 @@ int ion_buffer_destroy(struct ion_device *dev, struct ion_buffer *buffer)
 	}
 
 	heap = buffer->heap;
+	atomic_long_sub(buffer->size, &total_heap_bytes);
 
 	if (heap->flags & ION_HEAP_FLAG_DEFER_FREE)
 		ion_heap_freelist_add(heap, buffer);
@@ -251,3 +255,8 @@ void ion_buffer_kmap_put(struct ion_buffer *buffer)
 		buffer->vaddr = NULL;
 	}
 }
+
+u64 ion_get_total_heap_bytes(void)
+{
+	return atomic_long_read(&total_heap_bytes);
+}

drivers/staging/android/ion/ion_private.h

@@ -53,4 +53,6 @@ extern int ion_free(struct ion_buffer *buffer);
 /* ion heap helpers */
 extern int ion_heap_cleanup(struct ion_heap *heap);
 
+u64 ion_get_total_heap_bytes(void);
+
 #endif /* _ION_PRIVATE_H */

include/linux/ion.h

@@ -53,6 +53,7 @@ struct ion_buffer {
  * struct ion_heap_ops - ops to operate on a given heap
  * @allocate:		allocate memory
  * @free:		free memory
+ * @get_pool_size:	get pool size in pages
  *
  * allocate returns 0 on success, -errno on error.
  * map_dma and map_kernel return pointer on success, ERR_PTR on
@@ -67,6 +68,7 @@ struct ion_heap_ops {
 			unsigned long flags);
 	void (*free)(struct ion_buffer *buffer);
 	int (*shrink)(struct ion_heap *heap, gfp_t gfp_mask, int nr_to_scan);
+	long (*get_pool_size)(struct ion_heap *heap);
 };
 
 /**