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authorHui Zhu <zhuhui@xiaomi.com>2015-11-07 03:29:26 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-07 04:50:42 +0300
commit12a7bfad58cd604616dd5205efa6dc2be6f299eb (patch)
tree29228fe2c4440e1d95eeb64a8c19ef889f9bf744
parent8f958c98f28d088a1ef3e021ab7aeb59a234b953 (diff)
downloadlinux-12a7bfad58cd604616dd5205efa6dc2be6f299eb.tar.xz
zsmalloc: fix obj_to_head use page_private(page) as value but not pointer
In obj_malloc(): if (!class->huge) /* record handle in the header of allocated chunk */ link->handle = handle; else /* record handle in first_page->private */ set_page_private(first_page, handle); In the hugepage we save handle to private directly. But in obj_to_head(): if (class->huge) { VM_BUG_ON(!is_first_page(page)); return *(unsigned long *)page_private(page); } else return *(unsigned long *)obj; It is used as a pointer. The reason why there is no problem until now is huge-class page is born with ZS_FULL so it can't be migrated. However, we need this patch for future work: "VM-aware zsmalloced page migration" to reduce external fragmentation. Signed-off-by: Hui Zhu <zhuhui@xiaomi.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/zsmalloc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 4396b82fabaf..1fe9928d0ff1 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -825,7 +825,7 @@ static unsigned long obj_to_head(struct size_class *class, struct page *page,
{
if (class->huge) {
VM_BUG_ON(!is_first_page(page));
- return *(unsigned long *)page_private(page);
+ return page_private(page);
} else
return *(unsigned long *)obj;
}