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f2fs: merge two uchar variable in struct node_info to reduce memory cost 

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 <cm224.lee@samsung.com>
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
hifive-unleashed-5.1
Chao Yu 2014-12-18 17:37:21 +08:00 committed by Jaegeuk Kim
parent 3fa06d7bc9
commit 5c27f4ee44
2 changed files with 24 additions and 13 deletions
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4
fs/f2fs/node.c
View File

@ -269,7 +269,7 @@ 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) {
/*
@ -277,7 +277,7 @@ 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);
}

33
fs/f2fs/node.h
View File

@ -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)