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Date:   Thu, 12 Aug 2021 13:52:57 -0700
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Chao Yu <chao@kernel.org>
Cc:     Daeho Jeong <daeho43@gmail.com>, linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com,
        Daeho Jeong <daehojeong@google.com>
Subject: Re: [f2fs-dev] [PATCH v2] f2fs: introduce periodic iostat io latency
 traces
Message-ID: <YRWKKQe0bcgjKIIA@google.com>
References: <20210803225542.3487172-1-daeho43@gmail.com>
 <2a79c1c5-366b-92d9-4025-dbda660b1178@kernel.org>
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On 08/11, Chao Yu wrote:
> Hi Daeho,
> 
> On 2021/8/4 6:55, Daeho Jeong wrote:
> > From: Daeho Jeong <daehojeong@google.com>
> > 
> > Whenever we notice some sluggish issues on our machines, we are always
> > curious about how well all types of I/O in the f2fs filesystem are
> > handled. But, it's hard to get this kind of real data. First of all,
> > we need to reproduce the issue while turning on the profiling tool like
> > blktrace, but the issue doesn't happen again easily. Second, with the
> > intervention of any tools, the overall timing of the issue will be
> > slightly changed and it sometimes makes us hard to figure it out.
> > 
> > So, I added F2FS_IOSTAT_IO_LATENCY config option to support printing out
> > IO latency statistics tracepoint events which are minimal things to
> > understand filesystem's I/O related behaviors. With "iostat_enable" sysfs
> > node on, we can get this statistics info in a periodic way and it
> > would cause the least overhead.
> > 
> > [samples]
> >   f2fs_ckpt-254:1-507     [003] ....  2842.439683: f2fs_iostat_latency:
> > dev = (254,11), iotype [peak lat.(ms)/avg lat.(ms)/count],
> > rd_data [136/1/801], rd_node [136/1/1704], rd_meta [4/2/4],
> > wr_sync_data [164/16/3331], wr_sync_node [152/3/648],
> > wr_sync_meta [160/2/4243], wr_async_data [24/13/15],
> > wr_async_node [0/0/0], wr_async_meta [0/0/0]
> > 
> >   f2fs_ckpt-254:1-507     [002] ....  2845.450514: f2fs_iostat_latency:
> > dev = (254,11), iotype [peak lat.(ms)/avg lat.(ms)/count],
> > rd_data [60/3/456], rd_node [60/3/1258], rd_meta [0/0/1],
> > wr_sync_data [120/12/2285], wr_sync_node [88/5/428],
> > wr_sync_meta [52/6/2990], wr_async_data [4/1/3],
> > wr_async_node [0/0/0], wr_async_meta [0/0/0]
> > 
> > Signed-off-by: Daeho Jeong <daehojeong@google.com>
> > 
> > ---
> > v2: clean up with wrappers and fix a build breakage reported by
> >      kernel test robot <lkp@intel.com>
> > ---
> >   fs/f2fs/Kconfig             |   9 +++
> 
> I try to apply this patch in my local dev branch, but it failed due to
> conflicting with below commit, it needs to rebase this patch to last dev
> branch.

I applied this in dev branch. Could you please check?

> 
> https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git/commit/?h=dev&id=6b3ba1e77d8913ee6ffb3972e889bc35550ed95c
> 
> >   fs/f2fs/data.c              | 108 ++++++++++++++++++++++++++++++++++--
> >   fs/f2fs/f2fs.h              |  86 ++++++++++++++++++++++++++++
> >   fs/f2fs/super.c             |  11 +++-
> >   fs/f2fs/sysfs.c             |  44 +++++++++++++++
> >   include/trace/events/f2fs.h |  88 +++++++++++++++++++++++++++++
> >   6 files changed, 341 insertions(+), 5 deletions(-)
> > 
> > diff --git a/fs/f2fs/Kconfig b/fs/f2fs/Kconfig
> > index 7669de7b49ce..28dc5463bc87 100644
> > --- a/fs/f2fs/Kconfig
> > +++ b/fs/f2fs/Kconfig
> > @@ -135,3 +135,12 @@ config F2FS_FS_LZORLE
> >   	default y
> >   	help
> >   	  Support LZO-RLE compress algorithm, if unsure, say Y.
> > +
> > +config F2FS_IOSTAT_IO_LATENCY
> > +	bool "F2FS IO statistics IO latency information"
> > +	depends on F2FS_FS
> > +	default n
> > +	help
> > +	  Support printing out periodic IO latency statistics tracepoint
> > +	  events. With this, you have to turn on "iostat_enable" sysfs
> > +	  node to print this out.
> 
> This functionality looks independent, how about introuducing iostat.h
> and iostat.c (not sure, maybe trace.[hc])to include newly added structure
> and functions for dispersive codes cleanup.
> 
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index 948083c88d17..a2690f995b47 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -34,6 +34,12 @@ static struct kmem_cache *bio_entry_slab;
> >   static mempool_t *bio_post_read_ctx_pool;
> >   static struct bio_set f2fs_bioset;
> > +#ifdef CONFIG_F2FS_IOSTAT_IO_LATENCY
> > +#define NUM_PREALLOC_IOSTAT_CTXS	128
> > +static struct kmem_cache *bio_iostat_ctx_cache;
> > +static mempool_t *bio_iostat_ctx_pool;
> > +#endif
> > +
> >   #define	F2FS_BIO_POOL_SIZE	NR_CURSEG_TYPE
> >   int __init f2fs_init_bioset(void)
> > @@ -267,10 +273,67 @@ static void f2fs_post_read_work(struct work_struct *work)
> >   	f2fs_verify_and_finish_bio(ctx->bio);
> >   }
> > +#ifdef CONFIG_F2FS_IOSTAT_IO_LATENCY
> > +static inline void __update_and_unbind_iostat_ctx(struct bio *bio, int rw)
> > +{
> > +	struct bio_iostat_ctx *iostat_ctx = bio->bi_private;
> > +	int sync = bio->bi_opf & REQ_SYNC ? 0 : 1;
> 
> int sync = bio->bi_opf & REQ_SYNC ? 1 : 0;
> 
> > +
> > +	if (rw == 0)
> > +		bio->bi_private = iostat_ctx->post_read_ctx;
> > +	else
> > +		bio->bi_private = iostat_ctx->sbi;
> > +	__update_iostat_latency(iostat_ctx, rw, sync);
> > +	mempool_free(iostat_ctx, bio_iostat_ctx_pool);
> > +}
> > +
> > +static inline void __alloc_and_bind_iostat_ctx(struct f2fs_sb_info *sbi,
> > +		struct bio *bio, struct bio_post_read_ctx *ctx)
> > +{
> > +	struct bio_iostat_ctx *iostat_ctx;
> > +	/* Due to the mempool, this never fails. */
> > +	iostat_ctx = mempool_alloc(bio_iostat_ctx_pool, GFP_NOFS);
> > +	iostat_ctx->sbi = sbi;
> > +	iostat_ctx->submit_ts = 0;
> > +	iostat_ctx->type = 0;
> > +	iostat_ctx->post_read_ctx = ctx;
> > +	bio->bi_private = iostat_ctx;
> > +}
> > +
> > +static inline void __update_submit_iostat_ctx(struct bio *bio,
> > +		enum page_type type)
> > +{
> > +	struct bio_iostat_ctx *iostat_ctx = bio->bi_private;
> > +
> > +	iostat_ctx->submit_ts = jiffies;
> > +	iostat_ctx->type = type;
> > +}
> > +
> > +static inline struct bio_post_read_ctx *__get_post_read_ctx(struct bio *bio)
> > +{
> > +	struct bio_iostat_ctx *iostat_ctx = bio->bi_private;
> > +
> > +	return iostat_ctx->post_read_ctx;
> > +}
> > +#else
> > +static inline void __update_and_unbind_iostat_ctx(struct bio *bio, int rw) {}
> > +static inline void __alloc_and_bind_iostat_ctx(struct f2fs_sb_info *sbi,
> > +		struct bio *bio, struct bio_post_read_ctx *ctx) {}
> > +static inline void __update_submit_iostat_ctx(struct bio *bio,
> > +		enum page_type type) {}
> > +static inline struct bio_post_read_ctx *__get_post_read_ctx(struct bio *bio)
> > +{
> > +	return bio->bi_private;
> > +}
> > +#endif
> > +
> >   static void f2fs_read_end_io(struct bio *bio)
> >   {
> >   	struct f2fs_sb_info *sbi = F2FS_P_SB(bio_first_page_all(bio));
> > -	struct bio_post_read_ctx *ctx = bio->bi_private;
> > +	struct bio_post_read_ctx *ctx;
> > +
> > +	__update_and_unbind_iostat_ctx(bio, 0);
> > +	ctx = bio->bi_private;
> >   	if (time_to_inject(sbi, FAULT_READ_IO)) {
> >   		f2fs_show_injection_info(sbi, FAULT_READ_IO);
> > @@ -292,10 +355,13 @@ static void f2fs_read_end_io(struct bio *bio)
> >   static void f2fs_write_end_io(struct bio *bio)
> >   {
> > -	struct f2fs_sb_info *sbi = bio->bi_private;
> > +	struct f2fs_sb_info *sbi;
> >   	struct bio_vec *bvec;
> >   	struct bvec_iter_all iter_all;
> > +	__update_and_unbind_iostat_ctx(bio, 1);
> > +	sbi = bio->bi_private;
> > +
> >   	if (time_to_inject(sbi, FAULT_WRITE_IO)) {
> >   		f2fs_show_injection_info(sbi, FAULT_WRITE_IO);
> >   		bio->bi_status = BLK_STS_IOERR;
> > @@ -399,6 +465,8 @@ static struct bio *__bio_alloc(struct f2fs_io_info *fio, int npages)
> >   		bio->bi_write_hint = f2fs_io_type_to_rw_hint(sbi,
> >   						fio->type, fio->temp);
> >   	}
> > +	__alloc_and_bind_iostat_ctx(sbi, bio, NULL);
> > +
> >   	if (fio->io_wbc)
> >   		wbc_init_bio(fio->io_wbc, bio);
> > @@ -480,6 +548,9 @@ static inline void __submit_bio(struct f2fs_sb_info *sbi,
> >   		trace_f2fs_submit_read_bio(sbi->sb, type, bio);
> >   	else
> >   		trace_f2fs_submit_write_bio(sbi->sb, type, bio);
> > +
> > +	__update_submit_iostat_ctx(bio, type);
> > +
> >   	submit_bio(bio);
> >   }
> > @@ -971,7 +1042,7 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
> >   {
> >   	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> >   	struct bio *bio;
> > -	struct bio_post_read_ctx *ctx;
> > +	struct bio_post_read_ctx *ctx = NULL;
> >   	unsigned int post_read_steps = 0;
> >   	bio = bio_alloc_bioset(for_write ? GFP_NOIO : GFP_KERNEL,
> > @@ -1007,6 +1078,7 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
> >   		ctx->fs_blkaddr = blkaddr;
> >   		bio->bi_private = ctx;
> >   	}
> > +	__alloc_and_bind_iostat_ctx(sbi, bio, ctx);
> >   	return bio;
> >   }
> > @@ -2231,7 +2303,7 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
> >   		if (bio_add_page(bio, page, blocksize, 0) < blocksize)
> >   			goto submit_and_realloc;
> > -		ctx = bio->bi_private;
> > +		ctx = __get_post_read_ctx(bio);
> >   		ctx->enabled_steps |= STEP_DECOMPRESS;
> >   		refcount_inc(&dic->refcnt);
> > @@ -4132,6 +4204,34 @@ void f2fs_destroy_post_read_processing(void)
> >   	kmem_cache_destroy(bio_post_read_ctx_cache);
> >   }
> > +#ifdef CONFIG_F2FS_IOSTAT_IO_LATENCY
> > +int __init f2fs_init_iostat_processing(void)
> > +{
> > +	bio_iostat_ctx_cache =
> > +		kmem_cache_create("f2fs_bio_iostat_ctx",
> > +				  sizeof(struct bio_iostat_ctx), 0, 0, NULL);
> > +	if (!bio_iostat_ctx_cache)
> > +		goto fail;
> > +	bio_iostat_ctx_pool =
> > +		mempool_create_slab_pool(NUM_PREALLOC_IOSTAT_CTXS,
> > +					 bio_iostat_ctx_cache);
> > +	if (!bio_iostat_ctx_pool)
> > +		goto fail_free_cache;
> > +	return 0;
> > +
> > +fail_free_cache:
> > +	kmem_cache_destroy(bio_iostat_ctx_cache);
> > +fail:
> > +	return -ENOMEM;
> > +}
> > +
> > +void f2fs_destroy_iostat_processing(void)
> > +{
> > +	mempool_destroy(bio_iostat_ctx_pool);
> > +	kmem_cache_destroy(bio_iostat_ctx_cache);
> > +}
> > +#endif
> > +
> >   int f2fs_init_post_read_wq(struct f2fs_sb_info *sbi)
> >   {
> >   	if (!f2fs_sb_has_encrypt(sbi) &&
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 10a94ed839b1..fccee18ab776 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -1755,6 +1755,17 @@ struct f2fs_sb_info {
> >   	unsigned int compress_watermark;	/* cache page watermark */
> >   	atomic_t compress_page_hit;		/* cache hit count */
> >   #endif
> > +
> > +#ifdef CONFIG_F2FS_IOSTAT_IO_LATENCY
> > +	/* for io latency related statistics info in one iostat period */
> > +	spinlock_t iostat_lat_lock;
> > +	unsigned long rd_sum_lat[NR_PAGE_TYPE];		/* sum of read io latencies */
> > +	unsigned long rd_peak_lat[NR_PAGE_TYPE];	/* peak read io latency */
> > +	unsigned int rd_bio_cnt[NR_PAGE_TYPE];		/* read bio count */
> > +	unsigned long wr_sum_lat[2][NR_PAGE_TYPE];	/* sum of write io latencies (sync/async) */
> > +	unsigned long wr_peak_lat[2][NR_PAGE_TYPE];	/* peak write io latency (sync/async) */
> > +	unsigned int wr_bio_cnt[2][NR_PAGE_TYPE];	/* write bio count (sync/async) */
> 
> How about wrapping them in a structure? and we can move this into iostat.h?
> 
> > +#endif
> >   };
> >   struct f2fs_private_dio {
> > @@ -3233,6 +3244,26 @@ static inline void f2fs_reset_iostat(struct f2fs_sb_info *sbi)
> >   		sbi->prev_rw_iostat[i] = 0;
> >   	}
> >   	spin_unlock(&sbi->iostat_lock);
> > +
> > +#ifdef CONFIG_F2FS_IOSTAT_IO_LATENCY
> > +	spin_lock_irq(&sbi->iostat_lat_lock);
> > +	for (i = 0; i < NR_PAGE_TYPE; i++) {
> > +		sbi->rd_sum_lat[i] = 0;
> > +		sbi->rd_peak_lat[i] = 0;
> > +		sbi->rd_bio_cnt[i] = 0;
> > +	}
> > +
> > +	for (i = 0; i < 2; i++) {
> > +		int iotype;
> > +
> > +		for (iotype = 0; iotype < NR_PAGE_TYPE; iotype++) {
> > +			sbi->wr_sum_lat[i][iotype] = 0;
> > +			sbi->wr_peak_lat[i][iotype] = 0;
> > +			sbi->wr_bio_cnt[i][iotype] = 0;
> > +		}
> > +	}
> > +	spin_unlock_irq(&sbi->iostat_lat_lock);
> > +#endif
> >   }
> >   extern void f2fs_record_iostat(struct f2fs_sb_info *sbi);
> > @@ -3259,6 +3290,54 @@ static inline void f2fs_update_iostat(struct f2fs_sb_info *sbi,
> >   	f2fs_record_iostat(sbi);
> >   }
> > +#ifdef CONFIG_F2FS_IOSTAT_IO_LATENCY
> > +
> > +struct bio_post_read_ctx;
> > +
> > +struct bio_iostat_ctx {
> > +	struct f2fs_sb_info *sbi;
> > +	unsigned long submit_ts;
> > +	enum page_type type;
> > +	struct bio_post_read_ctx *post_read_ctx;
> > +};
> > +
> > +struct f2fs_iostat_latency {
> > +	unsigned int peak_lat;
> > +	unsigned int avg_lat;
> > +	unsigned int cnt;
> > +};
> > +
> > +static inline void __update_iostat_latency(struct bio_iostat_ctx *iostat_ctx,
> > +				int rw, int sync)
> > +{
> > +	unsigned long ts_diff;
> > +	unsigned int iotype = iostat_ctx->type;
> > +	unsigned long flags;
> > +	struct f2fs_sb_info *sbi = iostat_ctx->sbi;
> > +
> > +	if (!sbi->iostat_enable)
> > +		return;
> > +
> > +	ts_diff = jiffies - iostat_ctx->submit_ts;
> > +	if (iotype >= META_FLUSH)
> > +		iotype = META;
> > +
> > +	spin_lock_irqsave(&sbi->iostat_lat_lock, flags);
> > +	if (rw == 0) {
> > +		sbi->rd_sum_lat[iotype] += ts_diff;
> > +		sbi->rd_bio_cnt[iotype]++;
> > +		if (ts_diff > sbi->rd_peak_lat[iotype])
> > +			sbi->rd_peak_lat[iotype] = ts_diff;
> > +	} else {
> > +		sbi->wr_sum_lat[sync][iotype] += ts_diff;
> > +		sbi->wr_bio_cnt[sync][iotype]++;
> > +		if (ts_diff > sbi->wr_peak_lat[sync][iotype])
> > +			sbi->wr_peak_lat[sync][iotype] = ts_diff;
> > +	}
> > +	spin_unlock_irqrestore(&sbi->iostat_lat_lock, flags);
> > +}
> > +#endif
> > +
> >   #define __is_large_section(sbi)		((sbi)->segs_per_sec > 1)
> >   #define __is_meta_io(fio) (PAGE_TYPE_OF_BIO((fio)->type) == META)
> > @@ -3645,6 +3724,13 @@ bool f2fs_overwrite_io(struct inode *inode, loff_t pos, size_t len);
> >   void f2fs_clear_page_cache_dirty_tag(struct page *page);
> >   int f2fs_init_post_read_processing(void);
> >   void f2fs_destroy_post_read_processing(void);
> > +#ifdef CONFIG_F2FS_IOSTAT_IO_LATENCY
> > +int f2fs_init_iostat_processing(void);
> > +void f2fs_destroy_iostat_processing(void);
> > +#else
> > +static inline int f2fs_init_iostat_processing(void) { return 0; }
> > +static inline void f2fs_destroy_iostat_processing(void) {}
> > +#endif
> >   int f2fs_init_post_read_wq(struct f2fs_sb_info *sbi);
> >   void f2fs_destroy_post_read_wq(struct f2fs_sb_info *sbi);
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index 04aeb7c0df7d..9ead6d2e703b 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -3905,6 +3905,9 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> >   	/* init iostat info */
> >   	spin_lock_init(&sbi->iostat_lock);
> > +#ifdef CONFIG_F2FS_IOSTAT_IO_LATENCY
> > +	spin_lock_init(&sbi->iostat_lat_lock);
> > +#endif
> >   	sbi->iostat_enable = false;
> >   	sbi->iostat_period_ms = DEFAULT_IOSTAT_PERIOD_MS;
> > @@ -4415,9 +4418,12 @@ static int __init init_f2fs_fs(void)
> >   	err = f2fs_init_post_read_processing();
> >   	if (err)
> >   		goto free_root_stats;
> > -	err = f2fs_init_bio_entry_cache();
> > +	err = f2fs_init_iostat_processing();
> >   	if (err)
> >   		goto free_post_read;
> > +	err = f2fs_init_bio_entry_cache();
> > +	if (err)
> > +		goto free_iostat;
> >   	err = f2fs_init_bioset();
> >   	if (err)
> >   		goto free_bio_enrty_cache;
> > @@ -4439,6 +4445,8 @@ static int __init init_f2fs_fs(void)
> >   	f2fs_destroy_bioset();
> >   free_bio_enrty_cache:
> >   	f2fs_destroy_bio_entry_cache();
> > +free_iostat:
> > +	f2fs_destroy_iostat_processing();
> >   free_post_read:
> >   	f2fs_destroy_post_read_processing();
> >   free_root_stats:
> > @@ -4473,6 +4481,7 @@ static void __exit exit_f2fs_fs(void)
> >   	f2fs_destroy_compress_mempool();
> >   	f2fs_destroy_bioset();
> >   	f2fs_destroy_bio_entry_cache();
> > +	f2fs_destroy_iostat_processing();
> >   	f2fs_destroy_post_read_processing();
> >   	f2fs_destroy_root_stats();
> >   	unregister_filesystem(&f2fs_fs_type);
> > diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> > index f3a3aecbe111..4cb0561ec89d 100644
> > --- a/fs/f2fs/sysfs.c
> > +++ b/fs/f2fs/sysfs.c
> > @@ -1074,6 +1074,48 @@ static int __maybe_unused segment_bits_seq_show(struct seq_file *seq,
> >   	return 0;
> >   }
> > +#ifdef CONFIG_F2FS_IOSTAT_IO_LATENCY
> > +static inline void __record_iostat_latency(struct f2fs_sb_info *sbi)
> > +{
> > +	int io, sync, idx = 0;
> > +	unsigned int cnt;
> > +	struct f2fs_iostat_latency iostat_lat[3][NR_PAGE_TYPE];
> > +
> > +	spin_lock_irq(&sbi->iostat_lat_lock);
> > +	for (io = 0; io < NR_PAGE_TYPE; io++) {
> > +		cnt = sbi->rd_bio_cnt[io];
> > +		iostat_lat[idx][io].peak_lat =
> > +			jiffies_to_msecs(sbi->rd_peak_lat[io]);
> > +		iostat_lat[idx][io].cnt = cnt;
> > +		iostat_lat[idx][io].avg_lat = cnt ?
> > +			jiffies_to_msecs(sbi->rd_sum_lat[io]) / cnt : 0;
> > +		sbi->rd_sum_lat[io] = 0;
> > +		sbi->rd_peak_lat[io] = 0;
> > +		sbi->rd_bio_cnt[io] = 0;
> > +	}
> > +
> > +	for (sync = 0; sync < 2; sync++) {
> > +		idx++;
> > +		for (io = 0; io < NR_PAGE_TYPE; io++) {
> > +			cnt = sbi->wr_bio_cnt[sync][io];
> > +			iostat_lat[idx][io].peak_lat =
> > +			  jiffies_to_msecs(sbi->wr_peak_lat[sync][io]);
> > +			iostat_lat[idx][io].cnt = cnt;
> > +			iostat_lat[idx][io].avg_lat = cnt ?
> > +			  jiffies_to_msecs(sbi->wr_sum_lat[sync][io]) / cnt : 0;
> > +			sbi->wr_sum_lat[sync][io] = 0;
> > +			sbi->wr_peak_lat[sync][io] = 0;
> > +			sbi->wr_bio_cnt[sync][io] = 0;
> > +		}
> > +	}
> > +	spin_unlock_irq(&sbi->iostat_lat_lock);
> 
> What not defining read/write stat variables into the same array? so codes in
> __record_iostat_latency() and f2fs_reset_iostat() could be simplified.
> 
> enum {
> 	READ_IO,
> 	WRITE_ASYNC_IO,
> 	WRITE_SYNC_IO,
> 	MAX_IO_TYPE,
> };
> 
> 	unsigned long sum_lat[MAX_IO_TYPE][NR_PAGE_TYPE];	/* sum of io latencies */
> 	unsigned long peak_lat[MAX_IO_TYPE][NR_PAGE_TYPE];	/* peak io latency */
> 	unsigned int bio_cnt[MAX_IO_TYPE][NR_PAGE_TYPE];	/* bio count */
> 
> Thanks,
> 
> > +
> > +	trace_f2fs_iostat_latency(sbi, iostat_lat);
> > +}
> > +#else
> > +static inline void __record_iostat_latency(struct f2fs_sb_info *sbi) {}
> > +#endif
> > +
> >   void f2fs_record_iostat(struct f2fs_sb_info *sbi)
> >   {
> >   	unsigned long long iostat_diff[NR_IO_TYPE];
> > @@ -1099,6 +1141,8 @@ void f2fs_record_iostat(struct f2fs_sb_info *sbi)
> >   	spin_unlock(&sbi->iostat_lock);
> >   	trace_f2fs_iostat(sbi, iostat_diff);
> > +
> > +	__record_iostat_latency(sbi);
> >   }
> >   static int __maybe_unused iostat_info_seq_show(struct seq_file *seq,
> > diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
> > index 56b113e3cd6a..b9ede1b9207d 100644
> > --- a/include/trace/events/f2fs.h
> > +++ b/include/trace/events/f2fs.h
> > @@ -1894,6 +1894,94 @@ TRACE_EVENT(f2fs_iostat,
> >   		__entry->fs_cdrio, __entry->fs_nrio, __entry->fs_mrio)
> >   );
> > +#ifdef CONFIG_F2FS_IOSTAT_IO_LATENCY
> > +TRACE_EVENT(f2fs_iostat_latency,
> > +
> > +	TP_PROTO(struct f2fs_sb_info *sbi, struct f2fs_iostat_latency (*iostat_lat)[NR_PAGE_TYPE]),
> > +
> > +	TP_ARGS(sbi, iostat_lat),
> > +
> > +	TP_STRUCT__entry(
> > +		__field(dev_t,	dev)
> > +		__field(unsigned int,	d_rd_peak)
> > +		__field(unsigned int,	d_rd_avg)
> > +		__field(unsigned int,	d_rd_cnt)
> > +		__field(unsigned int,	n_rd_peak)
> > +		__field(unsigned int,	n_rd_avg)
> > +		__field(unsigned int,	n_rd_cnt)
> > +		__field(unsigned int,	m_rd_peak)
> > +		__field(unsigned int,	m_rd_avg)
> > +		__field(unsigned int,	m_rd_cnt)
> > +		__field(unsigned int,	d_wr_s_peak)
> > +		__field(unsigned int,	d_wr_s_avg)
> > +		__field(unsigned int,	d_wr_s_cnt)
> > +		__field(unsigned int,	n_wr_s_peak)
> > +		__field(unsigned int,	n_wr_s_avg)
> > +		__field(unsigned int,	n_wr_s_cnt)
> > +		__field(unsigned int,	m_wr_s_peak)
> > +		__field(unsigned int,	m_wr_s_avg)
> > +		__field(unsigned int,	m_wr_s_cnt)
> > +		__field(unsigned int,	d_wr_as_peak)
> > +		__field(unsigned int,	d_wr_as_avg)
> > +		__field(unsigned int,	d_wr_as_cnt)
> > +		__field(unsigned int,	n_wr_as_peak)
> > +		__field(unsigned int,	n_wr_as_avg)
> > +		__field(unsigned int,	n_wr_as_cnt)
> > +		__field(unsigned int,	m_wr_as_peak)
> > +		__field(unsigned int,	m_wr_as_avg)
> > +		__field(unsigned int,	m_wr_as_cnt)
> > +	),
> > +
> > +	TP_fast_assign(
> > +		__entry->dev		= sbi->sb->s_dev;
> > +		__entry->d_rd_peak	= iostat_lat[0][DATA].peak_lat;
> > +		__entry->d_rd_avg	= iostat_lat[0][DATA].avg_lat;
> > +		__entry->d_rd_cnt	= iostat_lat[0][DATA].cnt;
> > +		__entry->n_rd_peak	= iostat_lat[0][NODE].peak_lat;
> > +		__entry->n_rd_avg	= iostat_lat[0][NODE].avg_lat;
> > +		__entry->n_rd_cnt	= iostat_lat[0][NODE].cnt;
> > +		__entry->m_rd_peak	= iostat_lat[0][META].peak_lat;
> > +		__entry->m_rd_avg	= iostat_lat[0][META].avg_lat;
> > +		__entry->m_rd_cnt	= iostat_lat[0][META].cnt;
> > +		__entry->d_wr_s_peak	= iostat_lat[1][DATA].peak_lat;
> > +		__entry->d_wr_s_avg	= iostat_lat[1][DATA].avg_lat;
> > +		__entry->d_wr_s_cnt	= iostat_lat[1][DATA].cnt;
> > +		__entry->n_wr_s_peak	= iostat_lat[1][NODE].peak_lat;
> > +		__entry->n_wr_s_avg	= iostat_lat[1][NODE].avg_lat;
> > +		__entry->n_wr_s_cnt	= iostat_lat[1][NODE].cnt;
> > +		__entry->m_wr_s_peak	= iostat_lat[1][META].peak_lat;
> > +		__entry->m_wr_s_avg	= iostat_lat[1][META].avg_lat;
> > +		__entry->m_wr_s_cnt	= iostat_lat[1][META].cnt;
> > +		__entry->d_wr_as_peak	= iostat_lat[2][DATA].peak_lat;
> > +		__entry->d_wr_as_avg	= iostat_lat[2][DATA].avg_lat;
> > +		__entry->d_wr_as_cnt	= iostat_lat[2][DATA].cnt;
> > +		__entry->n_wr_as_peak	= iostat_lat[2][NODE].peak_lat;
> > +		__entry->n_wr_as_avg	= iostat_lat[2][NODE].avg_lat;
> > +		__entry->n_wr_as_cnt	= iostat_lat[2][NODE].cnt;
> > +		__entry->m_wr_as_peak	= iostat_lat[2][META].peak_lat;
> > +		__entry->m_wr_as_avg	= iostat_lat[2][META].avg_lat;
> > +		__entry->m_wr_as_cnt	= iostat_lat[2][META].cnt;
> > +	),
> > +
> > +	TP_printk("dev = (%d,%d), "
> > +		"iotype [peak lat.(ms)/avg lat.(ms)/count], "
> > +		"rd_data [%u/%u/%u], rd_node [%u/%u/%u], rd_meta [%u/%u/%u], "
> > +		"wr_sync_data [%u/%u/%u], wr_sync_node [%u/%u/%u], "
> > +		"wr_sync_meta [%u/%u/%u], wr_async_data [%u/%u/%u], "
> > +		"wr_async_node [%u/%u/%u], wr_async_meta [%u/%u/%u]",
> > +		show_dev(__entry->dev),
> > +		__entry->d_rd_peak, __entry->d_rd_avg, __entry->d_rd_cnt,
> > +		__entry->n_rd_peak, __entry->n_rd_avg, __entry->n_rd_cnt,
> > +		__entry->m_rd_peak, __entry->m_rd_avg, __entry->m_rd_cnt,
> > +		__entry->d_wr_s_peak, __entry->d_wr_s_avg, __entry->d_wr_s_cnt,
> > +		__entry->n_wr_s_peak, __entry->n_wr_s_avg, __entry->n_wr_s_cnt,
> > +		__entry->m_wr_s_peak, __entry->m_wr_s_avg, __entry->m_wr_s_cnt,
> > +		__entry->d_wr_as_peak, __entry->d_wr_as_avg, __entry->d_wr_as_cnt,
> > +		__entry->n_wr_as_peak, __entry->n_wr_as_avg, __entry->n_wr_as_cnt,
> > +		__entry->m_wr_as_peak, __entry->m_wr_as_avg, __entry->m_wr_as_cnt)
> > +);
> > +#endif
> > +
> >   TRACE_EVENT(f2fs_bmap,
> >   	TP_PROTO(struct inode *inode, sector_t lblock, sector_t pblock),
> > 
> 
> 
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