From 5c27f4ee447b4ef1cd88d5313eeb838c56265571 Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Thu, 18 Dec 2014 17:37:21 +0800 Subject: [PATCH] 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 Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- 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 cabecee88377..e565b9638971 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -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); } diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h index 036b887176ff..fa6f95968b42 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)