dm: eliminate some holes data structures
Eliminate a 4-byte hole in 'struct dm_io_memory' by moving 'offset' above the
'ptr' to which it applies (size reduced from 24 to 16 bytes). And by
association, 1-4 byte hole is eliminated in 'struct dm_io_request' (size
reduced from 56 to 48 bytes).
Eliminate all 6 4-byte holes and 1 cache-line in 'struct dm_snapshot' (size
reduced from 392 to 368 bytes).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/include/linux/dm-io.h b/include/linux/dm-io.h
index b6bf17e..5c9186b 100644
--- a/include/linux/dm-io.h
+++ b/include/linux/dm-io.h
@@ -37,14 +37,14 @@
struct dm_io_memory {
enum dm_io_mem_type type;
+ unsigned offset;
+
union {
struct page_list *pl;
struct bio_vec *bvec;
void *vma;
void *addr;
} ptr;
-
- unsigned offset;
};
struct dm_io_notify {