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authorDavid Sterba <dsterba@suse.com>2023-09-08 01:09:40 +0200
committerDavid Sterba <dsterba@suse.com>2023-10-12 16:44:04 +0200
commit321f4992c127458e51009b5160567b72e3442ff3 (patch)
treeeadd80fb5e1807ed1602334abd610b88805d6bfe /fs/btrfs/delayed-ref.h
parente41570d379b1dd6fe477a31b3b05191b6580f183 (diff)
btrfs: reduce size of struct btrfs_ref
We can reduce two members' size that in turn reduce size of struct btrfs_ref from 64 to 56 bytes. As the structure is often used as a local variable several functions reduce their stack usage. - make enum btrfs_ref_type packed, there are only 4 values - switch action and its values to a packed enum Final structure layout: struct btrfs_ref { enum btrfs_ref_type type; /* 0 1 */ enum btrfs_delayed_ref_action action; /* 1 1 */ bool skip_qgroup; /* 2 1 */ /* XXX 5 bytes hole, try to pack */ u64 bytenr; /* 8 8 */ u64 len; /* 16 8 */ u64 parent; /* 24 8 */ union { struct btrfs_data_ref data_ref; /* 32 24 */ struct btrfs_tree_ref tree_ref; /* 32 16 */ }; /* 32 24 */ /* size: 56, cachelines: 1, members: 7 */ /* sum members: 51, holes: 1, sum holes: 5 */ /* last cacheline: 56 bytes */ }; Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/delayed-ref.h')
-rw-r--r--fs/btrfs/delayed-ref.h18
1 files changed, 12 insertions, 6 deletions
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index fd9bf2b709c0..65d6dd42287d 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -9,10 +9,16 @@
#include <linux/refcount.h>
/* these are the possible values of struct btrfs_delayed_ref_node->action */
-#define BTRFS_ADD_DELAYED_REF 1 /* add one backref to the tree */
-#define BTRFS_DROP_DELAYED_REF 2 /* delete one backref from the tree */
-#define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */
-#define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */
+enum btrfs_delayed_ref_action {
+ /* Add one backref to the tree */
+ BTRFS_ADD_DELAYED_REF = 1,
+ /* Delete one backref from the tree */
+ BTRFS_DROP_DELAYED_REF,
+ /* Record a full extent allocation */
+ BTRFS_ADD_DELAYED_EXTENT,
+ /* Not changing ref count on head ref */
+ BTRFS_UPDATE_DELAYED_HEAD,
+} __packed;
struct btrfs_delayed_ref_node {
struct rb_node ref_node;
@@ -183,7 +189,7 @@ enum btrfs_ref_type {
BTRFS_REF_DATA,
BTRFS_REF_METADATA,
BTRFS_REF_LAST,
-};
+} __packed;
struct btrfs_data_ref {
/* For EXTENT_DATA_REF */
@@ -223,7 +229,7 @@ struct btrfs_tree_ref {
struct btrfs_ref {
enum btrfs_ref_type type;
- int action;
+ enum btrfs_delayed_ref_action action;
/*
* Whether this extent should go through qgroup record.