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-rw-r--r--mm/zsmalloc.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index a583ab111a43..5a532ebedc44 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -193,6 +193,7 @@ static struct vfsmount *zsmalloc_mnt;
* (see: fix_fullness_group())
*/
static const int fullness_threshold_frac = 4;
+static size_t huge_class_size;
struct size_class {
spinlock_t lock;
@@ -1407,6 +1408,25 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
}
EXPORT_SYMBOL_GPL(zs_unmap_object);
+/**
+ * zs_huge_class_size() - Returns the size (in bytes) of the first huge
+ * zsmalloc &size_class.
+ * @pool: zsmalloc pool to use
+ *
+ * The function returns the size of the first huge class - any object of equal
+ * or bigger size will be stored in zspage consisting of a single physical
+ * page.
+ *
+ * Context: Any context.
+ *
+ * Return: the size (in bytes) of the first huge zsmalloc &size_class.
+ */
+size_t zs_huge_class_size(struct zs_pool *pool)
+{
+ return huge_class_size;
+}
+EXPORT_SYMBOL_GPL(zs_huge_class_size);
+
static unsigned long obj_malloc(struct size_class *class,
struct zspage *zspage, unsigned long handle)
{
@@ -2364,6 +2384,27 @@ struct zs_pool *zs_create_pool(const char *name)
objs_per_zspage = pages_per_zspage * PAGE_SIZE / size;
/*
+ * We iterate from biggest down to smallest classes,
+ * so huge_class_size holds the size of the first huge
+ * class. Any object bigger than or equal to that will
+ * endup in the huge class.
+ */
+ if (pages_per_zspage != 1 && objs_per_zspage != 1 &&
+ !huge_class_size) {
+ huge_class_size = size;
+ /*
+ * The object uses ZS_HANDLE_SIZE bytes to store the
+ * handle. We need to subtract it, because zs_malloc()
+ * unconditionally adds handle size before it performs
+ * size class search - so object may be smaller than
+ * huge class size, yet it still can end up in the huge
+ * class because it grows by ZS_HANDLE_SIZE extra bytes
+ * right before class lookup.
+ */
+ huge_class_size -= (ZS_HANDLE_SIZE - 1);
+ }
+
+ /*
* size_class is used for normal zsmalloc operation such
* as alloc/free for that size. Although it is natural that we
* have one size_class for each size, there is a chance that we