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Date: Sun, 14 Apr 2024 15:19:23 +0000
From: Jaegeuk Kim <jaegeuk@kernel.org>
To: Chao Yu <chao@kernel.org>
Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org,
	Daeho Jeong <daeho43@gmail.com>
Subject: Re: [PATCH v3] f2fs: zone: don't block IO if there is remained open
 zone
Message-ID: <Zhvz-_pqlCEZrUHB@google.com>
References: <20240407135848.3638669-1-chao@kernel.org>
 <Zhmje71C7FOTIfom@google.com>
 <2ca3cb91-1db5-4a9b-9dd0-8caad2d09f31@kernel.org>
Precedence: bulk
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In-Reply-To: <2ca3cb91-1db5-4a9b-9dd0-8caad2d09f31@kernel.org>

It seems this caused kernel hang. Chao, have you tested this patch enough?

On 04/13, Chao Yu wrote:
> On 2024/4/13 5:11, Jaegeuk Kim wrote:
> > On 04/07, Chao Yu wrote:
> > > max open zone may be larger than log header number of f2fs, for
> > > such case, it doesn't need to wait last IO in previous zone, let's
> > > introduce available_open_zone semaphore, and reduce it once we
> > > submit first write IO in a zone, and increase it after completion
> > > of last IO in the zone.
> > > 
> > > Cc: Daeho Jeong <daeho43@gmail.com>
> > > Signed-off-by: Chao Yu <chao@kernel.org>
> > > ---
> > > v3:
> > > - avoid race condition in between __submit_merged_bio()
> > > and __allocate_new_segment().
> > >   fs/f2fs/data.c    | 105 ++++++++++++++++++++++++++++++----------------
> > >   fs/f2fs/f2fs.h    |  34 ++++++++++++---
> > >   fs/f2fs/iostat.c  |   7 ++++
> > >   fs/f2fs/iostat.h  |   2 +
> > >   fs/f2fs/segment.c |  43 ++++++++++++++++---
> > >   fs/f2fs/segment.h |  12 +++++-
> > >   fs/f2fs/super.c   |   2 +
> > >   7 files changed, 156 insertions(+), 49 deletions(-)
> > > 
> > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > > index 0d88649c60a5..18a4ac0a06bc 100644
> > > --- a/fs/f2fs/data.c
> > > +++ b/fs/f2fs/data.c
> > > @@ -373,11 +373,10 @@ static void f2fs_write_end_io(struct bio *bio)
> > >   #ifdef CONFIG_BLK_DEV_ZONED
> > >   static void f2fs_zone_write_end_io(struct bio *bio)
> > >   {
> > > -	struct f2fs_bio_info *io = (struct f2fs_bio_info *)bio->bi_private;
> > > +	struct f2fs_sb_info *sbi = iostat_get_bio_private(bio);
> > > -	bio->bi_private = io->bi_private;
> > > -	complete(&io->zone_wait);
> > >   	f2fs_write_end_io(bio);
> > > +	up(&sbi->available_open_zones);
> > >   }
> > >   #endif
> > > @@ -531,6 +530,24 @@ static void __submit_merged_bio(struct f2fs_bio_info *io)
> > >   	if (!io->bio)
> > >   		return;
> > > +#ifdef CONFIG_BLK_DEV_ZONED
> > > +	if (io->open_zone) {
> > > +		/*
> > > +		 * if there is no open zone, it will wait for last IO in
> > > +		 * previous zone before submitting new IO.
> > > +		 */
> > > +		down(&fio->sbi->available_open_zones);
> > > +		io->open_zone = false;
> > > +		io->zone_openned = true;
> > > +	}
> > > +
> > > +	if (io->close_zone) {
> > > +		io->bio->bi_end_io = f2fs_zone_write_end_io;
> > > +		io->zone_openned = false;
> > > +		io->close_zone = false;
> > > +	}
> > > +#endif
> > > +
> > >   	if (is_read_io(fio->op)) {
> > >   		trace_f2fs_prepare_read_bio(io->sbi->sb, fio->type, io->bio);
> > >   		f2fs_submit_read_bio(io->sbi, io->bio, fio->type);
> > > @@ -601,9 +618,9 @@ int f2fs_init_write_merge_io(struct f2fs_sb_info *sbi)
> > >   			INIT_LIST_HEAD(&sbi->write_io[i][j].bio_list);
> > >   			init_f2fs_rwsem(&sbi->write_io[i][j].bio_list_lock);
> > >   #ifdef CONFIG_BLK_DEV_ZONED
> > > -			init_completion(&sbi->write_io[i][j].zone_wait);
> > > -			sbi->write_io[i][j].zone_pending_bio = NULL;
> > > -			sbi->write_io[i][j].bi_private = NULL;
> > > +			sbi->write_io[i][j].open_zone = false;
> > > +			sbi->write_io[i][j].zone_openned = false;
> > > +			sbi->write_io[i][j].close_zone = false;
> > >   #endif
> > >   		}
> > >   	}
> > > @@ -634,6 +651,31 @@ static void __f2fs_submit_merged_write(struct f2fs_sb_info *sbi,
> > >   	f2fs_up_write(&io->io_rwsem);
> > >   }
> > > +void f2fs_blkzoned_submit_merged_write(struct f2fs_sb_info *sbi, int type)
> > > +{
> > > +#ifdef CONFIG_BLK_DEV_ZONED
> > > +	struct f2fs_bio_info *io;
> > > +
> > > +	if (!f2fs_sb_has_blkzoned(sbi))
> > > +		return;
> > > +
> > > +	io = sbi->write_io[PAGE_TYPE(type)] + type_to_temp(type);
> > > +
> > > +	f2fs_down_write(&io->io_rwsem);
> > > +	if (io->zone_openned) {
> > > +		if (io->bio) {
> > > +			io->close_zone = true;
> > > +			__submit_merged_bio(io);
> > > +		} else if (io->zone_openned) {
> > > +			up(&sbi->available_open_zones);
> > > +			io->zone_openned = false;
> > > +		}
> > > +	}
> > > +	f2fs_up_write(&io->io_rwsem);
> > > +#endif
> > > +
> > > +}
> > > +
> > >   static void __submit_merged_write_cond(struct f2fs_sb_info *sbi,
> > >   				struct inode *inode, struct page *page,
> > >   				nid_t ino, enum page_type type, bool force)
> > > @@ -918,22 +960,16 @@ int f2fs_merge_page_bio(struct f2fs_io_info *fio)
> > >   }
> > >   #ifdef CONFIG_BLK_DEV_ZONED
> > > -static bool is_end_zone_blkaddr(struct f2fs_sb_info *sbi, block_t blkaddr)
> > > +static bool is_blkaddr_zone_boundary(struct f2fs_sb_info *sbi,
> > > +					block_t blkaddr, bool start)
> > >   {
> > > -	int devi = 0;
> > > +	if (!f2fs_blkaddr_in_seqzone(sbi, blkaddr))
> > > +		return false;
> > > +
> > > +	if (start)
> > > +		return (blkaddr % sbi->blocks_per_blkz) == 0;
> > > +	return (blkaddr % sbi->blocks_per_blkz == sbi->blocks_per_blkz - 1);
> > > -	if (f2fs_is_multi_device(sbi)) {
> > > -		devi = f2fs_target_device_index(sbi, blkaddr);
> > > -		if (blkaddr < FDEV(devi).start_blk ||
> > > -		    blkaddr > FDEV(devi).end_blk) {
> > > -			f2fs_err(sbi, "Invalid block %x", blkaddr);
> > > -			return false;
> > > -		}
> > > -		blkaddr -= FDEV(devi).start_blk;
> > > -	}
> > > -	return bdev_is_zoned(FDEV(devi).bdev) &&
> > > -		f2fs_blkz_is_seq(sbi, devi, blkaddr) &&
> > > -		(blkaddr % sbi->blocks_per_blkz == sbi->blocks_per_blkz - 1);
> > >   }
> > >   #endif
> > > @@ -944,20 +980,14 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
> > >   	struct f2fs_bio_info *io = sbi->write_io[btype] + fio->temp;
> > >   	struct page *bio_page;
> > >   	enum count_type type;
> > > +#ifdef CONFIG_BLK_DEV_ZONED
> > > +	bool blkzoned = f2fs_sb_has_blkzoned(sbi) && btype < META;
> > > +#endif
> > >   	f2fs_bug_on(sbi, is_read_io(fio->op));
> > >   	f2fs_down_write(&io->io_rwsem);
> > >   next:
> > > -#ifdef CONFIG_BLK_DEV_ZONED
> > > -	if (f2fs_sb_has_blkzoned(sbi) && btype < META && io->zone_pending_bio) {
> > > -		wait_for_completion_io(&io->zone_wait);
> > > -		bio_put(io->zone_pending_bio);
> > > -		io->zone_pending_bio = NULL;
> > > -		io->bi_private = NULL;
> > > -	}
> > > -#endif
> > > -
> > >   	if (fio->in_list) {
> > >   		spin_lock(&io->io_lock);
> > >   		if (list_empty(&io->io_list)) {
> > > @@ -985,6 +1015,11 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
> > >   	type = WB_DATA_TYPE(bio_page, fio->compressed_page);
> > >   	inc_page_count(sbi, type);
> > > +#ifdef CONFIG_BLK_DEV_ZONED
> > > +	if (blkzoned && is_blkaddr_zone_boundary(sbi, fio->new_blkaddr, true))
> > > +		io->open_zone = true;
> > > +#endif
> > > +
> > >   	if (io->bio &&
> > >   	    (!io_is_mergeable(sbi, io->bio, io, fio, io->last_block_in_bio,
> > >   			      fio->new_blkaddr) ||
> > > @@ -1010,15 +1045,11 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
> > >   	io->last_block_in_bio = fio->new_blkaddr;
> > >   	trace_f2fs_submit_page_write(fio->page, fio);
> > > +
> > >   #ifdef CONFIG_BLK_DEV_ZONED
> > > -	if (f2fs_sb_has_blkzoned(sbi) && btype < META &&
> > > -			is_end_zone_blkaddr(sbi, fio->new_blkaddr)) {
> > > -		bio_get(io->bio);
> > > -		reinit_completion(&io->zone_wait);
> > > -		io->bi_private = io->bio->bi_private;
> > > -		io->bio->bi_private = io;
> > > -		io->bio->bi_end_io = f2fs_zone_write_end_io;
> > > -		io->zone_pending_bio = io->bio;
> > > +	if (blkzoned &&
> > > +		is_blkaddr_zone_boundary(sbi, fio->new_blkaddr, false)) {
> > > +		io->close_zone = true;
> > >   		__submit_merged_bio(io);
> > >   	}
> > >   #endif
> > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > > index 694f8a52cb84..8a26530cf4fb 100644
> > > --- a/fs/f2fs/f2fs.h
> > > +++ b/fs/f2fs/f2fs.h
> > > @@ -1234,16 +1234,16 @@ 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. */
> > > -#ifdef CONFIG_BLK_DEV_ZONED
> > > -	struct completion zone_wait;	/* condition value for the previous open zone to close */
> > > -	struct bio *zone_pending_bio;	/* pending bio for the previous zone */
> > > -	void *bi_private;		/* previous bi_private for pending bio */
> > > -#endif
> > >   	struct f2fs_rwsem io_rwsem;	/* blocking op for bio */
> > >   	spinlock_t io_lock;		/* serialize DATA/NODE IOs */
> > >   	struct list_head io_list;	/* track fios */
> > >   	struct list_head bio_list;	/* bio entry list head */
> > >   	struct f2fs_rwsem bio_list_lock;	/* lock to protect bio entry list */
> > > +#ifdef CONFIG_BLK_DEV_ZONED
> > > +	bool open_zone;			/* open a zone */
> > > +	bool zone_openned;		/* zone has been openned */
> > > +	bool close_zone;		/* close a zone */
> > > +#endif
> > >   };
> > >   #define FDEV(i)				(sbi->devs[i])
> > > @@ -1560,6 +1560,7 @@ struct f2fs_sb_info {
> > >   #ifdef CONFIG_BLK_DEV_ZONED
> > >   	unsigned int blocks_per_blkz;		/* F2FS blocks per zone */
> > >   	unsigned int max_open_zones;		/* max open zone resources of the zoned device */
> > > +	struct semaphore available_open_zones;	/* available open zones */
> > >   #endif
> > >   	/* for node-related operations */
> > > @@ -3822,6 +3823,7 @@ void f2fs_destroy_bio_entry_cache(void);
> > >   void f2fs_submit_read_bio(struct f2fs_sb_info *sbi, struct bio *bio,
> > >   			  enum page_type type);
> > >   int f2fs_init_write_merge_io(struct f2fs_sb_info *sbi);
> > > +void f2fs_blkzoned_submit_merged_write(struct f2fs_sb_info *sbi, int type);
> > >   void f2fs_submit_merged_write(struct f2fs_sb_info *sbi, enum page_type type);
> > >   void f2fs_submit_merged_write_cond(struct f2fs_sb_info *sbi,
> > >   				struct inode *inode, struct page *page,
> > > @@ -4469,6 +4471,28 @@ static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi, int devi,
> > >   	return test_bit(zno, FDEV(devi).blkz_seq);
> > >   }
> > > +
> > > +static inline bool f2fs_blkaddr_in_seqzone(struct f2fs_sb_info *sbi,
> > > +							block_t blkaddr)
> > > +{
> > > +	int devi = 0;
> > > +
> > > +	if (f2fs_is_multi_device(sbi)) {
> > > +		devi = f2fs_target_device_index(sbi, blkaddr);
> > > +		if (blkaddr < FDEV(devi).start_blk ||
> > > +		    blkaddr > FDEV(devi).end_blk) {
> > > +			f2fs_err(sbi, "Invalid block %x", blkaddr);
> > > +			return false;
> > > +		}
> > > +		blkaddr -= FDEV(devi).start_blk;
> > > +	}
> > > +
> > > +	if (!bdev_is_zoned(FDEV(devi).bdev) ||
> > > +		!f2fs_blkz_is_seq(sbi, devi, blkaddr))
> > > +		return false;
> > > +
> > > +	return true;
> > 
> > Applied as below.
> > 
> > @@ -4485,11 +4485,8 @@ static inline bool f2fs_blkaddr_in_seqzone(struct f2fs_sb_info *sbi,
> >                  blkaddr -= FDEV(devi).start_blk;
> >          }
> > 
> > -       if (!bdev_is_zoned(FDEV(devi).bdev) ||
> > -               !f2fs_blkz_is_seq(sbi, devi, blkaddr))
> > -               return false;
> > -
> > -       return true;
> > +       return bdev_is_zoned(FDEV(devi).bdev) &&
> > +               f2fs_blkz_is_seq(sbi, devi, blkaddr);
> 
> Looks good, thank you for cleanup.
> 
> Thanks,
> 
> >   }
> >   #endif
> > 
> > > +}
> > >   #endif
> > >   static inline int f2fs_bdev_index(struct f2fs_sb_info *sbi,
> > > diff --git a/fs/f2fs/iostat.c b/fs/f2fs/iostat.c
> > > index f8703038e1d8..a8626e297876 100644
> > > --- a/fs/f2fs/iostat.c
> > > +++ b/fs/f2fs/iostat.c
> > > @@ -237,6 +237,13 @@ static inline void __update_iostat_latency(struct bio_iostat_ctx *iostat_ctx,
> > >   	spin_unlock_irqrestore(&sbi->iostat_lat_lock, flags);
> > >   }
> > > +void *iostat_get_bio_private(struct bio *bio)
> > > +{
> > > +	struct bio_iostat_ctx *iostat_ctx = bio->bi_private;
> > > +
> > > +	return iostat_ctx->sbi;
> > > +}
> > > +
> > >   void iostat_update_and_unbind_ctx(struct bio *bio)
> > >   {
> > >   	struct bio_iostat_ctx *iostat_ctx = bio->bi_private;
> > > diff --git a/fs/f2fs/iostat.h b/fs/f2fs/iostat.h
> > > index eb99d05cf272..9006c3d41590 100644
> > > --- a/fs/f2fs/iostat.h
> > > +++ b/fs/f2fs/iostat.h
> > > @@ -58,6 +58,7 @@ static inline struct bio_post_read_ctx *get_post_read_ctx(struct bio *bio)
> > >   	return iostat_ctx->post_read_ctx;
> > >   }
> > > +extern void *iostat_get_bio_private(struct bio *bio);
> > >   extern void iostat_update_and_unbind_ctx(struct bio *bio);
> > >   extern void iostat_alloc_and_bind_ctx(struct f2fs_sb_info *sbi,
> > >   		struct bio *bio, struct bio_post_read_ctx *ctx);
> > > @@ -68,6 +69,7 @@ extern void f2fs_destroy_iostat(struct f2fs_sb_info *sbi);
> > >   #else
> > >   static inline void f2fs_update_iostat(struct f2fs_sb_info *sbi, struct inode *inode,
> > >   		enum iostat_type type, unsigned long long io_bytes) {}
> > > +static inline void *iostat_get_bio_private(struct bio *bio) { return bio->bi_private; }
> > >   static inline void iostat_update_and_unbind_ctx(struct bio *bio) {}
> > >   static inline void iostat_alloc_and_bind_ctx(struct f2fs_sb_info *sbi,
> > >   		struct bio *bio, struct bio_post_read_ctx *ctx) {}
> > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > index 4fd76e867e0a..4a3cf2888faf 100644
> > > --- a/fs/f2fs/segment.c
> > > +++ b/fs/f2fs/segment.c
> > > @@ -3140,6 +3140,9 @@ static int __allocate_new_segment(struct f2fs_sb_info *sbi, int type,
> > >   		return err;
> > >   	stat_inc_seg_type(sbi, curseg);
> > >   	locate_dirty_segment(sbi, old_segno);
> > > +
> > > +	f2fs_blkzoned_submit_merged_write(sbi, type);
> > > +
> > >   	return 0;
> > >   }
> > > @@ -3461,12 +3464,7 @@ static int __get_segment_type(struct f2fs_io_info *fio)
> > >   		f2fs_bug_on(fio->sbi, true);
> > >   	}
> > > -	if (IS_HOT(type))
> > > -		fio->temp = HOT;
> > > -	else if (IS_WARM(type))
> > > -		fio->temp = WARM;
> > > -	else
> > > -		fio->temp = COLD;
> > > +	fio->temp = type_to_temp(type);
> > >   	return type;
> > >   }
> > > @@ -4132,6 +4130,27 @@ static int restore_curseg_summaries(struct f2fs_sb_info *sbi)
> > >   		return -EINVAL;
> > >   	}
> > > +#ifdef CONFIG_BLK_DEV_ZONED
> > > +	if (f2fs_sb_has_blkzoned(sbi)) {
> > > +		for (type = 0; type < NR_PERSISTENT_LOG; type++) {
> > > +			struct curseg_info *curseg = CURSEG_I(sbi, type);
> > > +			enum page_type ptype;
> > > +			enum temp_type temp;
> > > +
> > > +			if (!(curseg->next_blkoff % sbi->blocks_per_blkz))
> > > +				continue;
> > > +
> > > +			if (!f2fs_blkaddr_in_seqzone(sbi,
> > > +					START_BLOCK(sbi, curseg->segno)))
> > > +				continue;
> > > +
> > > +			ptype = PAGE_TYPE(type);
> > > +			temp = type_to_temp(type);
> > > +			down(&sbi->available_open_zones);
> > > +			sbi->write_io[ptype][temp].zone_openned = true;
> > > +		}
> > > +	}
> > > +#endif
> > >   	return 0;
> > >   }
> > > @@ -5451,6 +5470,18 @@ static void destroy_curseg(struct f2fs_sb_info *sbi)
> > >   	for (i = 0; i < NR_CURSEG_TYPE; i++) {
> > >   		kfree(array[i].sum_blk);
> > >   		kfree(array[i].journal);
> > > +
> > > +#ifdef CONFIG_BLK_DEV_ZONED
> > > +		if (f2fs_sb_has_blkzoned(sbi)) {
> > > +			enum page_type ptype = PAGE_TYPE(i);
> > > +			enum temp_type temp = type_to_temp(i);
> > > +
> > > +			if (sbi->write_io[ptype][temp].zone_openned) {
> > > +				up(&sbi->available_open_zones);
> > > +				sbi->write_io[ptype][temp].zone_openned = false;
> > > +			}
> > > +		}
> > > +#endif
> > >   	}
> > >   	kfree(array);
> > >   }
> > > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> > > index e1c0f418aa11..855978ca869f 100644
> > > --- a/fs/f2fs/segment.h
> > > +++ b/fs/f2fs/segment.h
> > > @@ -24,7 +24,8 @@
> > >   #define IS_DATASEG(t)	((t) <= CURSEG_COLD_DATA)
> > >   #define IS_NODESEG(t)	((t) >= CURSEG_HOT_NODE && (t) <= CURSEG_COLD_NODE)
> > > -#define SE_PAGETYPE(se)	((IS_NODESEG((se)->type) ? NODE : DATA))
> > > +#define PAGE_TYPE(t)	(IS_NODESEG(t) ? NODE : DATA)
> > > +#define SE_PAGETYPE(se)	(PAGE_TYPE((se)->type))
> > >   static inline void sanity_check_seg_type(struct f2fs_sb_info *sbi,
> > >   						unsigned short seg_type)
> > > @@ -965,3 +966,12 @@ static inline unsigned int first_zoned_segno(struct f2fs_sb_info *sbi)
> > >   			return GET_SEGNO(sbi, FDEV(devi).start_blk);
> > >   	return 0;
> > >   }
> > > +
> > > +static inline enum temp_type type_to_temp(int type)
> > > +{
> > > +	if (IS_HOT(type))
> > > +		return HOT;
> > > +	else if (IS_WARM(type))
> > > +		return WARM;
> > > +	return COLD;
> > > +}
> > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > > index fdf358c7f808..954baa6c100d 100644
> > > --- a/fs/f2fs/super.c
> > > +++ b/fs/f2fs/super.c
> > > @@ -3893,6 +3893,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
> > >   				sbi->max_open_zones, F2FS_OPTION(sbi).active_logs);
> > >   			return -EINVAL;
> > >   		}
> > > +
> > > +		sema_init(&sbi->available_open_zones, sbi->max_open_zones);
> > >   	}
> > >   	zone_sectors = bdev_zone_sectors(bdev);
> > > -- 
> > > 2.40.1