Hi > -----Original Message----- > From: Jaegeuk Kim [mailto:jaegeuk.kim@xxxxxxxxxxx] > Sent: Tuesday, November 19, 2013 11:36 AM > To: Chao Yu > Cc: linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: [f2fs-dev] [PATCH] f2fs: split sbi->write_mutex for DATA/NODE/META to > avoid unnecessary race > > Hi, > > I think we don't need to make two patches for this. > How about this? This could be reasonable, And I will refer to this patch. > > From 71c27f78e72d680edcd7b1c0917842343044653c Mon Sep 17 00:00:00 2001 > From: Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx> > Date: Mon, 18 Nov 2013 17:16:17 +0900 > Subject: [PATCH] f2fs: use sbi->write_mutex for write bios > > This patch removes an unnecessary semaphore (i.e., sbi->bio_sem). > There is no reason to use the semaphore when f2fs submits read and write > IOs. > Instead, let's use a write mutex and cover the sbi->bio[] by the lock. > > Change log from v1: > o split write_mutex suggested by Chao Yu > > Chao described, > "All DATA/NODE/META bio buffers in superblock is protected by > 'sbi->write_mutex', but each bio buffer area is independent, So we > should split write_mutex to three for DATA/NODE/META." > > Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx> > Signed-off-by: Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx> > --- > fs/f2fs/data.c | 4 ---- > fs/f2fs/f2fs.h | 2 +- > fs/f2fs/segment.c | 13 +++++++++---- > fs/f2fs/super.c | 6 +++++- > 4 files changed, 15 insertions(+), 10 deletions(-) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 076a60c..5920639 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -383,8 +383,6 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct > page *page, > > trace_f2fs_readpage(page, blk_addr, type); > > - down_read(&sbi->bio_sem); > - > /* Allocate a new bio */ > bio = f2fs_bio_alloc(bdev, 1); > > @@ -394,13 +392,11 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct > page *page, > > if (bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) { > bio_put(bio); > - up_read(&sbi->bio_sem); > f2fs_put_page(page, 1); > return -EFAULT; > } > > submit_bio(type, bio); > - up_read(&sbi->bio_sem); > return 0; > } > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index 6a49554..6e67f28 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -374,7 +374,7 @@ struct f2fs_sb_info { > struct f2fs_sm_info *sm_info; /* segment manager */ > struct bio *bio[NR_PAGE_TYPE]; /* bios to merge */ > sector_t last_block_in_bio[NR_PAGE_TYPE]; /* last block number */ > - struct rw_semaphore bio_sem; /* IO semaphore */ > + struct mutex write_mutex[NR_PAGE_TYPE]; /* mutex for writing IOs */ > > /* for checkpoint */ > struct f2fs_checkpoint *ckpt; /* raw checkpoint pointer */ > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index dad5f1a..119af0b 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -871,9 +871,14 @@ static void do_submit_bio(struct f2fs_sb_info *sbi, > > void f2fs_submit_bio(struct f2fs_sb_info *sbi, enum page_type type, > bool sync) > { > - down_write(&sbi->bio_sem); > + enum page_type btype = PAGE_TYPE_OF_BIO(type); > + > + if (!sbi->bio[btype]) > + return; > + > + mutex_lock(&sbi->write_mutex[btype]); > do_submit_bio(sbi, type, sync); > - up_write(&sbi->bio_sem); > + mutex_unlock(&sbi->write_mutex[btype]); > } > > static void submit_write_page(struct f2fs_sb_info *sbi, struct page > *page, > @@ -884,7 +889,7 @@ static void submit_write_page(struct f2fs_sb_info > *sbi, struct page *page, > > verify_block_addr(sbi, blk_addr); > > - down_write(&sbi->bio_sem); > + mutex_lock(&sbi->write_mutex[type]); > > inc_page_count(sbi, F2FS_WRITEBACK); > > @@ -919,7 +924,7 @@ retry: > > sbi->last_block_in_bio[type] = blk_addr; > > - up_write(&sbi->bio_sem); > + mutex_unlock(&sbi->write_mutex[type]); > trace_f2fs_submit_write_page(page, blk_addr, type); > } > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > index a022412..e194578 100644 > --- a/fs/f2fs/super.c > +++ b/fs/f2fs/super.c > @@ -820,6 +820,7 @@ static int f2fs_fill_super(struct super_block *sb, > void *data, int silent) > struct buffer_head *raw_super_buf; > struct inode *root; > long err = -EINVAL; > + int i; > > /* allocate memory for f2fs-specific super block info */ > sbi = kzalloc(sizeof(struct f2fs_sb_info), GFP_KERNEL); > @@ -876,7 +877,10 @@ static int f2fs_fill_super(struct super_block *sb, > void *data, int silent) > mutex_init(&sbi->node_write); > sbi->por_doing = false; > spin_lock_init(&sbi->stat_lock); > - init_rwsem(&sbi->bio_sem); > + > + for (i = 0; i < NR_PAGE_TYPE; i++) > + mutex_init(&sbi->write_mutex[i]); > + > init_rwsem(&sbi->cp_rwsem); > init_waitqueue_head(&sbi->cp_wait); > init_sb_info(sbi); > -- > 1.8.4.474.g128a96c > > > > -- > Jaegeuk Kim > Samsung -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
