percpu: manage chunks based on contig_bits instead of free_bytes
authorDennis Zhou <dennis@kernel.org>
Mon, 25 Feb 2019 21:43:38 +0000 (13:43 -0800)
committerDennis Zhou <dennis@kernel.org>
Wed, 13 Mar 2019 19:25:31 +0000 (12:25 -0700)
When a chunk becomes fragmented, it can end up having a large number of
small allocation areas free. The free_bytes sorting of chunks leads to
unnecessary checking of chunks that cannot satisfy the allocation.
Switch to contig_bits sorting to prevent scanning chunks that may not be
able to service the allocation request.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
mm/percpu.c

index cbace9e..fc1e8ef 100644 (file)
@@ -234,7 +234,7 @@ static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
        if (chunk->free_bytes < PCPU_MIN_ALLOC_SIZE || chunk->contig_bits == 0)
                return 0;
 
-       return pcpu_size_to_slot(chunk->free_bytes);
+       return pcpu_size_to_slot(chunk->contig_bits * PCPU_MIN_ALLOC_SIZE);
 }
 
 /* set the pointer to a chunk in a page struct */