On 2016/10/19 2:48, Jaegeuk Kim wrote:
> We don't need to allocate bio partially in order to maximize sequential
> writes.
We are going to allocate bio with max size supposing that there will be more
opportunity to merge small IOs into one bio. Otherwise, if MAX_BIO_BLOCKS is
smaller than BIO_MAX_PAGES, less IOs can be merged. Is my understanding correct?
Thanks,
>
> Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
> ---
> fs/f2fs/checkpoint.c | 2 +-
> fs/f2fs/data.c | 4 +---
> fs/f2fs/node.c | 3 +--
> fs/f2fs/segment.c | 4 ++--
> fs/f2fs/segment.h | 17 +++--------------
> 5 files changed, 8 insertions(+), 22 deletions(-)
>
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index 654f5d7..157b7fd 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -228,7 +228,7 @@ void ra_meta_pages_cond(struct f2fs_sb_info *sbi, pgoff_t
> index)
> f2fs_put_page(page, 0);
>
> if (readahead)
> - ra_meta_pages(sbi, index, MAX_BIO_BLOCKS(sbi), META_POR, true);
> + ra_meta_pages(sbi, index, BIO_MAX_PAGES, META_POR, true);
> }
>
> static int f2fs_write_meta_page(struct page *page,
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 77cd9ac..fe8ce5a 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -307,10 +307,8 @@ void f2fs_submit_page_mbio(struct f2fs_io_info *fio)
> __submit_merged_bio(io);
> alloc_new:
> if (io->bio == NULL) {
> - int bio_blocks = MAX_BIO_BLOCKS(sbi);
> -
> io->bio = __bio_alloc(sbi, fio->new_blkaddr,
> - bio_blocks, is_read);
> + BIO_MAX_PAGES, is_read);
> io->fio = *fio;
> }
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 69c42e2..285e2a5 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -2101,7 +2101,6 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
> struct f2fs_node *rn;
> struct f2fs_summary *sum_entry;
> block_t addr;
> - int bio_blocks = MAX_BIO_BLOCKS(sbi);
> int i, idx, last_offset, nrpages;
>
> /* scan the node segment */
> @@ -2110,7 +2109,7 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
> sum_entry = &sum->entries[0];
>
> for (i = 0; i < last_offset; i += nrpages, addr += nrpages) {
> - nrpages = min(last_offset - i, bio_blocks);
> + nrpages = min(last_offset - i, BIO_MAX_PAGES);
>
> /* readahead node pages */
> ra_meta_pages(sbi, addr, nrpages, META_POR, true);
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 7a7e3f1..a21a1a3 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -2355,10 +2355,10 @@ static void build_sit_entries(struct f2fs_sb_info
> *sbi)
> int sit_blk_cnt = SIT_BLK_CNT(sbi);
> unsigned int i, start, end;
> unsigned int readed, start_blk = 0;
> - int nrpages = MAX_BIO_BLOCKS(sbi) * 8;
>
> do {
> - readed = ra_meta_pages(sbi, start_blk, nrpages, META_SIT, true);
> + readed = ra_meta_pages(sbi, start_blk, BIO_MAX_PAGES,
> + META_SIT, true);
>
> start = start_blk * sit_i->sents_per_block;
> end = (start_blk + readed) * sit_i->sents_per_block;
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> index a6efb5c..d8ff069 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -102,8 +102,6 @@
> (((sector_t)blk_addr) << F2FS_LOG_SECTORS_PER_BLOCK)
> #define SECTOR_TO_BLOCK(sectors) \
> (sectors >> F2FS_LOG_SECTORS_PER_BLOCK)
> -#define MAX_BIO_BLOCKS(sbi) \
> - ((int)min((int)max_hw_blocks(sbi), BIO_MAX_PAGES))
>
> /*
> * indicate a block allocation direction: RIGHT and LEFT.
> @@ -698,13 +696,6 @@ static inline bool sec_usage_check(struct f2fs_sb_info
> *sbi, unsigned int secno)
> return false;
> }
>
> -static inline unsigned int max_hw_blocks(struct f2fs_sb_info *sbi)
> -{
> - struct block_device *bdev = sbi->sb->s_bdev;
> - struct request_queue *q = bdev_get_queue(bdev);
> - return SECTOR_TO_BLOCK(queue_max_sectors(q));
> -}
> -
> /*
> * It is very important to gather dirty pages and write at once, so that we
> can
> * submit a big bio without interfering other data writes.
> @@ -722,7 +713,7 @@ static inline int nr_pages_to_skip(struct f2fs_sb_info
> *sbi, int type)
> else if (type == NODE)
> return 8 * sbi->blocks_per_seg;
> else if (type == META)
> - return 8 * MAX_BIO_BLOCKS(sbi);
> + return 8 * BIO_MAX_PAGES;
> else
> return 0;
> }
> @@ -739,11 +730,9 @@ static inline long nr_pages_to_write(struct f2fs_sb_info
> *sbi, int type,
> return 0;
>
> nr_to_write = wbc->nr_to_write;
> -
> + desired = BIO_MAX_PAGES;
> if (type == NODE)
> - desired = 2 * max_hw_blocks(sbi);
> - else
> - desired = MAX_BIO_BLOCKS(sbi);
> + desired <<= 1;
>
> wbc->nr_to_write = desired;
> return desired - nr_to_write;
>
