f2fs: reduce stack memory cost by using bitfield in struct f2fs_io_info

This patch tries to use bitfield in struct f2fs_io_info to improve
memory usage.

struct f2fs_io_info {
...
	unsigned int need_lock:8;	/* indicate we need to lock cp_rwsem */
	unsigned int version:8;		/* version of the node */
	unsigned int submitted:1;	/* indicate IO submission */
	unsigned int in_list:1;		/* indicate fio is in io_list */
	unsigned int is_por:1;		/* indicate IO is from recovery or not */
	unsigned int retry:1;		/* need to reallocate block address */
	unsigned int encrypted:1;	/* indicate file is encrypted */
	unsigned int post_read:1;	/* require post read */
...
};

After this patch, size of struct f2fs_io_info reduces from 136 to 120.

[Nathan: fix a compile warning (single-bit-bitfield-constant-conversion)]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 7e2b44db1587..89ce08b0ff7c 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -70,7 +70,7 @@ static struct page *__get_meta_page(struct f2fs_sb_info *sbi, pgoff_t index,
 		.old_blkaddr = index,
 		.new_blkaddr = index,
 		.encrypted_page = NULL,
-		.is_por = !is_meta,
+		.is_por = !is_meta ? 1 : 0,
 	};
 	int err;
 
@@ -237,8 +237,8 @@ int f2fs_ra_meta_pages(struct f2fs_sb_info *sbi, block_t start, int nrpages,
 		.op = REQ_OP_READ,
 		.op_flags = sync ? (REQ_META | REQ_PRIO) : REQ_RAHEAD,
 		.encrypted_page = NULL,
-		.in_list = false,
-		.is_por = (type == META_POR),
+		.in_list = 0,
+		.is_por = (type == META_POR) ? 1 : 0,
 	};
 	struct blk_plug plug;
 	int err;