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authorDavid Sterba <dsterba@suse.com>2015-11-30 16:51:29 +0100
committerDavid Sterba <dsterba@suse.com>2016-01-07 14:26:58 +0100
commit35b3ad50baa4a5fc2ae616c0513d2987bfb52a85 (patch)
tree94400b470771eef5e41f663b722d67aa0bb8e179 /fs/btrfs/delayed-ref.h
parent8089fe62c6603860f6796ca80519b92391292f21 (diff)
btrfs: better packing of btrfs_delayed_extent_op
btrfs_delayed_extent_op can be packed in a better way, it's 40 bytes now and has 8 unused bytes. Reducing the level type to u8 makes it possible to squeeze it to the padding byte after key. The bitfields were switched to bool as there's space to store the full byte without increasing the whole structure, besides that the generated assembly is smaller. struct btrfs_delayed_extent_op { struct btrfs_disk_key key; /* 0 17 */ u8 level; /* 17 1 */ bool update_key; /* 18 1 */ bool update_flags; /* 19 1 */ bool is_data; /* 20 1 */ /* XXX 3 bytes hole, try to pack */ u64 flags_to_set; /* 24 8 */ /* size: 32, cachelines: 1, members: 6 */ /* sum members: 29, holes: 1, sum holes: 3 */ /* last cacheline: 32 bytes */ }; The final size is 32 bytes which gives +26 object per slab page. text data bss dec hex filename 938811 43670 23144 1005625 f5839 fs/btrfs/btrfs.ko.before 938747 43670 23144 1005561 f57f9 fs/btrfs/btrfs.ko.after Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/delayed-ref.h')
-rw-r--r--fs/btrfs/delayed-ref.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index 00ed02cbf3e9..c24b653c7343 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -75,11 +75,11 @@ struct btrfs_delayed_ref_node {
struct btrfs_delayed_extent_op {
struct btrfs_disk_key key;
+ u8 level;
+ bool update_key;
+ bool update_flags;
+ bool is_data;
u64 flags_to_set;
- int level;
- unsigned int update_key:1;
- unsigned int update_flags:1;
- unsigned int is_data:1;
};
/*