From: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
We only need to save the position (pfn + obj_idx) in the handle, don't
need to save tag bit in handle. So one more bit can be used as obj_idx.
Actually, the tag bit is only useful in zspage's memory space, to tell
if an object is allocated or not.
Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
---
mm/zsmalloc.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 63ec385cd670..7d7cb3eaabe0 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -110,7 +110,7 @@
#define OBJ_TAG_BITS 1
#define OBJ_TAG_MASK OBJ_ALLOCATED_TAG
-#define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS - OBJ_TAG_BITS)
+#define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS)
#define OBJ_INDEX_MASK ((_AC(1, UL) << OBJ_INDEX_BITS) - 1)
#define HUGE_BITS 1
@@ -737,14 +737,12 @@ static struct page *get_next_page(struct page *page)
static void obj_to_location(unsigned long obj, struct page **page,
unsigned int *obj_idx)
{
- obj >>= OBJ_TAG_BITS;
*page = pfn_to_page(obj >> OBJ_INDEX_BITS);
*obj_idx = (obj & OBJ_INDEX_MASK);
}
static void obj_to_page(unsigned long obj, struct page **page)
{
- obj >>= OBJ_TAG_BITS;
*page = pfn_to_page(obj >> OBJ_INDEX_BITS);
}
@@ -759,7 +757,6 @@ static unsigned long location_to_obj(struct page *page, unsigned int obj_idx)
obj = page_to_pfn(page) << OBJ_INDEX_BITS;
obj |= obj_idx & OBJ_INDEX_MASK;
- obj <<= OBJ_TAG_BITS;
return obj;
}
--
2.40.1
