f2fs: avoid unnecessary bio submit when wait page writeback

This patch introduce is_merged_page() to check whether current page is merged
in f2fs bio cache. When page is not in cache, we can avoid submitting bio cache,
resulting in having more chance to merge pages.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index b0c923aef229bc69ddc43c01ef1f894435a550f6..598bfa617a7ec15c72165f54e58408eba6d5905f 100644 (file)
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -134,7 +134,7 @@ void f2fs_submit_merged_bio(struct f2fs_sb_info *sbi,
 
        io = is_read_io(rw) ? &sbi->read_io : &sbi->write_io[btype];
 
-       mutex_lock(&io->io_mutex);
+       down_write(&io->io_rwsem);
 
        /* change META to META_FLUSH in the checkpoint procedure */
        if (type >= META_FLUSH) {
@@ -142,7 +142,7 @@ void f2fs_submit_merged_bio(struct f2fs_sb_info *sbi,
                io->fio.rw = WRITE_FLUSH_FUA | REQ_META | REQ_PRIO;
        }
        __submit_merged_bio(io);
-       mutex_unlock(&io->io_mutex);
+       up_write(&io->io_rwsem);
 }
 
 /*
@@ -180,7 +180,7 @@ void f2fs_submit_page_mbio(struct f2fs_sb_info *sbi, struct page *page,
 
        verify_block_addr(sbi, blk_addr);
 
-       mutex_lock(&io->io_mutex);
+       down_write(&io->io_rwsem);
 
        if (!is_read)
                inc_page_count(sbi, F2FS_WRITEBACK);
@@ -204,7 +204,7 @@ alloc_new:
 
        io->last_block_in_bio = blk_addr;
 
-       mutex_unlock(&io->io_mutex);
+       up_write(&io->io_rwsem);
        trace_f2fs_submit_page_mbio(page, fio->rw, fio->type, blk_addr);
 }
 

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index f83433e4b043d2ef27177bb7765d460e135a8b65..1e3d869b60cdbb3300110635a569933191c5b144 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -394,7 +394,7 @@ struct f2fs_bio_info {
        struct bio *bio;                /* bios to merge */
        sector_t last_block_in_bio;     /* last block number */
        struct f2fs_io_info fio;        /* store buffered io info. */
-       struct mutex io_mutex;          /* mutex for bio */
+       struct rw_semaphore io_rwsem;   /* blocking op for bio */
 };
 
 struct f2fs_sb_info {

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index e7ff23a536a400872bb63592ac1ea4d370906cfb..570ab9a084c5bab4bd2bbfd723e32c608c77d444 100644 (file)
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1046,12 +1046,38 @@ void rewrite_node_page(struct f2fs_sb_info *sbi,
        mutex_unlock(&curseg->curseg_mutex);
 }
 
+static inline bool is_merged_page(struct f2fs_sb_info *sbi,
+                                       struct page *page, enum page_type type)
+{
+       enum page_type btype = PAGE_TYPE_OF_BIO(type);
+       struct f2fs_bio_info *io = &sbi->write_io[btype];
+       struct bio *bio = io->bio;
+       struct bio_vec *bvec;
+       int i;
+
+       down_read(&io->io_rwsem);
+       if (!bio)
+               goto out;
+
+       bio_for_each_segment_all(bvec, bio, i) {
+               if (page == bvec->bv_page) {
+                       up_read(&io->io_rwsem);
+                       return true;
+               }
+       }
+
+out:
+       up_read(&io->io_rwsem);
+       return false;
+}
+
 void f2fs_wait_on_page_writeback(struct page *page,
                                enum page_type type)
 {
        struct f2fs_sb_info *sbi = F2FS_SB(page->mapping->host->i_sb);
        if (PageWriteback(page)) {
-               f2fs_submit_merged_bio(sbi, type, WRITE);
+               if (is_merged_page(sbi, page, type))
+                       f2fs_submit_merged_bio(sbi, type, WRITE);
                wait_on_page_writeback(page);
        }
 }

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 89ea046c846db16f113801503becb29833656b42..959834066d607fd7f17522dfed6cc48375423588 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -920,11 +920,11 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
        sbi->por_doing = false;
        spin_lock_init(&sbi->stat_lock);
 
-       mutex_init(&sbi->read_io.io_mutex);
+       init_rwsem(&sbi->read_io.io_rwsem);
        sbi->read_io.sbi = sbi;
        sbi->read_io.bio = NULL;
        for (i = 0; i < NR_PAGE_TYPE; i++) {
-               mutex_init(&sbi->write_io[i].io_mutex);
+               init_rwsem(&sbi->write_io[i].io_rwsem);
                sbi->write_io[i].sbi = sbi;
                sbi->write_io[i].bio = NULL;
        }