This patch moves one member of struct nat_entry: _flag_ to struct node_info,
so _version_ in struct node_info and _flag_ which are unsigned char type will
merge to one 32-bit space in register/memory. So the size of nat_entry will be
reduced from 28 bytes to 24 bytes (for 64-bit machine, reduce its size from 40
bytes to 32 bytes) and then slab memory using by f2fs will be reduced.
changes from v2:
o update description of memory usage gain for 64-bit machine suggested by
Changman Lee.
changes from v1:
o introduce inline copy_node_info() to copy valid data from node info suggested
by Jaegeuk Kim, it can avoid bug.
Reviewed-by: Changman Lee <[email protected]>
Signed-off-by: Chao Yu <[email protected]>
---
fs/f2fs/node.c | 4 ++--
fs/f2fs/node.h | 33 ++++++++++++++++++++++-----------
2 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index f83326c..5aa54a0 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -268,7 +268,7 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
e = __lookup_nat_cache(nm_i, ni->nid);
if (!e) {
e = grab_nat_entry(nm_i, ni->nid);
- e->ni = *ni;
+ copy_node_info(&e->ni, ni);
f2fs_bug_on(sbi, ni->blk_addr == NEW_ADDR);
} else if (new_blkaddr == NEW_ADDR) {
/*
@@ -276,7 +276,7 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
* previous nat entry can be remained in nat cache.
* So, reinitialize it with new information.
*/
- e->ni = *ni;
+ copy_node_info(&e->ni, ni);
f2fs_bug_on(sbi, ni->blk_addr != NULL_ADDR);
}
diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
index d10b644..eb59167 100644
--- a/fs/f2fs/node.h
+++ b/fs/f2fs/node.h
@@ -29,6 +29,14 @@
/* return value for read_node_page */
#define LOCKED_PAGE 1
+/* For flag in struct node_info */
+enum {
+ IS_CHECKPOINTED, /* is it checkpointed before? */
+ HAS_FSYNCED_INODE, /* is the inode fsynced before? */
+ HAS_LAST_FSYNC, /* has the latest node fsync mark? */
+ IS_DIRTY, /* this nat entry is dirty? */
+};
+
/*
* For node information
*/
@@ -37,18 +45,11 @@ struct node_info {
nid_t ino; /* inode number of the node's owner */
block_t blk_addr; /* block address of the node */
unsigned char version; /* version of the node */
-};
-
-enum {
- IS_CHECKPOINTED, /* is it checkpointed before? */
- HAS_FSYNCED_INODE, /* is the inode fsynced before? */
- HAS_LAST_FSYNC, /* has the latest node fsync mark? */
- IS_DIRTY, /* this nat entry is dirty? */
+ unsigned char flag; /* for node information bits */
};
struct nat_entry {
struct list_head list; /* for clean or dirty nat list */
- unsigned char flag; /* for node information bits */
struct node_info ni; /* in-memory node information */
};
@@ -63,20 +64,30 @@ struct nat_entry {
#define inc_node_version(version) (++version)
+static inline void copy_node_info(struct node_info *dst,
+ struct node_info *src)
+{
+ dst->nid = src->nid;
+ dst->ino = src->ino;
+ dst->blk_addr = src->blk_addr;
+ dst->version = src->version;
+ /* should not copy flag here */
+}
+
static inline void set_nat_flag(struct nat_entry *ne,
unsigned int type, bool set)
{
unsigned char mask = 0x01 << type;
if (set)
- ne->flag |= mask;
+ ne->ni.flag |= mask;
else
- ne->flag &= ~mask;
+ ne->ni.flag &= ~mask;
}
static inline bool get_nat_flag(struct nat_entry *ne, unsigned int type)
{
unsigned char mask = 0x01 << type;
- return ne->flag & mask;
+ return ne->ni.flag & mask;
}
static inline void nat_reset_flag(struct nat_entry *ne)
--
2.1.2