[PATCH v3] f2fs: reduce stack memory cost by using bitfield in struct f2fs_io_info

From: Chao Yu
Date: Thu Feb 02 2023 - 02:05:12 EST


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@xxxxxxxxxx>
Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
---
v3:
- merge Nathan's patch which fixes a compile warning (single-bit-bitfield-
constant-conversion).
fs/f2fs/checkpoint.c | 6 +++---
fs/f2fs/compress.c | 5 +++--
fs/f2fs/data.c | 10 +++++-----
fs/f2fs/f2fs.h | 18 +++++++++---------
fs/f2fs/gc.c | 8 ++++----
fs/f2fs/node.c | 2 +-
fs/f2fs/segment.c | 6 +++---
7 files changed, 28 insertions(+), 27 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 641165c82992..5c481824a4c6 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;
diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index b196b881f3bb..a469cdde6bac 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -1213,10 +1213,11 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
.page = NULL,
.encrypted_page = NULL,
.compressed_page = NULL,
- .submitted = false,
+ .submitted = 0,
.io_type = io_type,
.io_wbc = wbc,
- .encrypted = fscrypt_inode_uses_fs_layer_crypto(cc->inode),
+ .encrypted = fscrypt_inode_uses_fs_layer_crypto(cc->inode) ?
+ 1 : 0,
};
struct dnode_of_data dn;
struct node_info ni;
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index c940da1c540f..754841bce389 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -992,7 +992,7 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
bio_page = fio->page;

/* set submitted = true as a return value */
- fio->submitted = true;
+ fio->submitted = 1;

inc_page_count(sbi, WB_DATA_TYPE(bio_page));

@@ -1008,7 +1008,7 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
(fio->type == DATA || fio->type == NODE) &&
fio->new_blkaddr & F2FS_IO_SIZE_MASK(sbi)) {
dec_page_count(sbi, WB_DATA_TYPE(bio_page));
- fio->retry = true;
+ fio->retry = 1;
goto skip;
}
io->bio = __bio_alloc(fio, BIO_MAX_VECS);
@@ -2776,10 +2776,10 @@ int f2fs_write_single_data_page(struct page *page, int *submitted,
.old_blkaddr = NULL_ADDR,
.page = page,
.encrypted_page = NULL,
- .submitted = false,
+ .submitted = 0,
.compr_blocks = compr_blocks,
.need_lock = LOCK_RETRY,
- .post_read = f2fs_post_read_required(inode),
+ .post_read = f2fs_post_read_required(inode) ? 1 : 0,
.io_type = io_type,
.io_wbc = wbc,
.bio = bio,
@@ -2900,7 +2900,7 @@ int f2fs_write_single_data_page(struct page *page, int *submitted,
}

if (submitted)
- *submitted = fio.submitted ? 1 : 0;
+ *submitted = fio.submitted;

return 0;

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index f3c5f7740c1a..5449c8277339 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1210,19 +1210,19 @@ struct f2fs_io_info {
struct page *encrypted_page; /* encrypted page */
struct page *compressed_page; /* compressed page */
struct list_head list; /* serialize IOs */
- bool submitted; /* indicate IO submission */
- int need_lock; /* indicate we need to lock cp_rwsem */
- bool in_list; /* indicate fio is in io_list */
- bool is_por; /* indicate IO is from recovery or not */
- bool retry; /* need to reallocate block address */
- int compr_blocks; /* # of compressed block addresses */
- bool encrypted; /* indicate file is encrypted */
- bool post_read; /* require post read */
+ unsigned int compr_blocks; /* # of compressed block addresses */
+ 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 */
enum iostat_type io_type; /* io type */
struct writeback_control *io_wbc; /* writeback control */
struct bio **bio; /* bio for ipu */
sector_t *last_block; /* last block number in bio */
- unsigned char version; /* version of the node */
};

struct bio_entry {
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 97e846263c7c..0a9dfa459860 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1156,8 +1156,8 @@ static int ra_data_block(struct inode *inode, pgoff_t index)
.op = REQ_OP_READ,
.op_flags = 0,
.encrypted_page = NULL,
- .in_list = false,
- .retry = false,
+ .in_list = 0,
+ .retry = 0,
};
int err;

@@ -1245,8 +1245,8 @@ static int move_data_block(struct inode *inode, block_t bidx,
.op = REQ_OP_READ,
.op_flags = 0,
.encrypted_page = NULL,
- .in_list = false,
- .retry = false,
+ .in_list = 0,
+ .retry = 0,
};
struct dnode_of_data dn;
struct f2fs_summary sum;
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index fbd1d25fecc2..19a1fee88a36 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1586,7 +1586,7 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted,
.op_flags = wbc_to_write_flags(wbc),
.page = page,
.encrypted_page = NULL,
- .submitted = false,
+ .submitted = 0,
.io_type = io_type,
.io_wbc = wbc,
};
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index f46a8c0daeb3..69b01b5c0ce0 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -3314,10 +3314,10 @@ void f2fs_allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
struct f2fs_bio_info *io;

if (F2FS_IO_ALIGNED(sbi))
- fio->retry = false;
+ fio->retry = 0;

INIT_LIST_HEAD(&fio->list);
- fio->in_list = true;
+ fio->in_list = 1;
io = sbi->write_io[fio->type] + fio->temp;
spin_lock(&io->io_lock);
list_add_tail(&fio->list, &io->io_list);
@@ -3398,7 +3398,7 @@ void f2fs_do_write_meta_page(struct f2fs_sb_info *sbi, struct page *page,
.new_blkaddr = page->index,
.page = page,
.encrypted_page = NULL,
- .in_list = false,
+ .in_list = 0,
};

if (unlikely(page->index >= MAIN_BLKADDR(sbi)))
--
2.25.1