From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chao Yu Subject: [f2fs-dev][PATCH] f2fs: merge two uchar variable in struct nat_entry to reduce memory cost Date: Mon, 08 Dec 2014 15:13:49 +0800 Message-ID: <001c01d012b6$a0fbaaa0$e2f2ffe0$@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Content-language: zh-cn Sender: linux-kernel-owner@vger.kernel.org To: Jaegeuk Kim , Changman Lee Cc: linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-f2fs-devel.lists.sourceforge.net This patch moves one member of struct nat_entry: _flag_ to struct node_info, so _version_ in struct node_info and _flag_ with unsigned char type will merge to one 32-bit space in register/memory. Then the size of nat_entry will reduce its size from 28 bytes to 24 bytes and slab memory using by f2fs will be reduced. Signed-off-by: Chao Yu --- fs/f2fs/node.h | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h index d10b644..27a7318 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 */ }; @@ -68,15 +69,15 @@ static inline void set_nat_flag(struct nat_entry *ne, { 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