percpu: renew the max_contig if we merge the head and previous block

During pcpu_alloc_area(), we might merge the current head with the
previous block. Since we have calculated the max_contig using the
size of previous block before we skip it, and now we update the size
of previous block, so we should renew the max_contig.

Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/mm/percpu.c b/mm/percpu.c
index 202e104df8a7..63e24fb4387b 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -473,9 +473,11 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
                  * uncommon for percpu allocations.
                  */
                 if (head && (head < sizeof(int) || !(p[-1] & 1))) {
+                        *p = off += head;
                         if (p[-1] & 1)
                                 chunk->free_size -= head;
-                        *p = off += head;
+                        else
+                                max_contig = max(*p - p[-1], max_contig);
                         this_size -= head;
                         head = 0;
                 }