Re: [PATCH] f2fs: use iostat_lat_type directly as a parameter in the iostat_update_and_unbind_ctx()

[Jaegeuk Kim]

On 01/28, Chao Yu wrote:
> On 2023/1/5 12:22, Yangtao Li wrote:
> > Convert to use iostat_lat_type as parameter instead of raw number.
> > BTW, move NUM_PREALLOC_IOSTAT_CTXS to the header file, and rename
> > iotype to page_type to match the definition.
> > 
> > Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
> > ---
> >   fs/f2fs/data.c   |  5 +++--
> >   fs/f2fs/iostat.c | 34 +++++++++++-----------------------
> >   fs/f2fs/iostat.h | 19 ++++++++++---------
> >   3 files changed, 24 insertions(+), 34 deletions(-)
> > 
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index c940da1c540f..4e8fd5697c42 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -292,7 +292,7 @@ static void f2fs_read_end_io(struct bio *bio)
> >   	struct bio_post_read_ctx *ctx;
> >   	bool intask = in_task();
> > -	iostat_update_and_unbind_ctx(bio, 0);
> > +	iostat_update_and_unbind_ctx(bio, READ_IO);
> >   	ctx = bio->bi_private;
> >   	if (time_to_inject(sbi, FAULT_READ_IO))
> > @@ -330,7 +330,8 @@ static void f2fs_write_end_io(struct bio *bio)
> >   	struct bio_vec *bvec;
> >   	struct bvec_iter_all iter_all;
> > -	iostat_update_and_unbind_ctx(bio, 1);
> > +	iostat_update_and_unbind_ctx(bio, bio->bi_opf & REQ_SYNC ? WRITE_SYNC_IO :
> > +										WRITE_ASYNC_IO);
> 
> We can use op_is_write(bio_op(bio)) to check IO's rw type, why not just
> passing bio arguement, and parse rw/sync types from bio inside
> iostat_update_and_unbind_ctx(), it can avoid passing unneeded arguements.

Chao, let's write another patch to clean up, if you're interested in.

> 
> Thanks,
> 
> >   	sbi = bio->bi_private;
> >   	if (time_to_inject(sbi, FAULT_WRITE_IO))
> > diff --git a/fs/f2fs/iostat.c b/fs/f2fs/iostat.c
> > index 59c72f92191a..20944c4a683a 100644
> > --- a/fs/f2fs/iostat.c
> > +++ b/fs/f2fs/iostat.c
> > @@ -14,7 +14,6 @@
> >   #include "iostat.h"
> >   #include <trace/events/f2fs.h>
> > -#define NUM_PREALLOC_IOSTAT_CTXS	128
> >   static struct kmem_cache *bio_iostat_ctx_cache;
> >   static mempool_t *bio_iostat_ctx_pool;
> > @@ -210,49 +209,38 @@ void f2fs_update_iostat(struct f2fs_sb_info *sbi, struct inode *inode,
> >   }
> >   static inline void __update_iostat_latency(struct bio_iostat_ctx *iostat_ctx,
> > -				int rw, bool is_sync)
> > +				enum iostat_lat_type type)
> >   {
> >   	unsigned long ts_diff;
> > -	unsigned int iotype = iostat_ctx->type;
> > +	unsigned int page_type = iostat_ctx->type;
> >   	struct f2fs_sb_info *sbi = iostat_ctx->sbi;
> >   	struct iostat_lat_info *io_lat = sbi->iostat_io_lat;
> > -	int idx;
> >   	unsigned long flags;
> >   	if (!sbi->iostat_enable)
> >   		return;
> >   	ts_diff = jiffies - iostat_ctx->submit_ts;
> > -	if (iotype >= META_FLUSH)
> > -		iotype = META;
> > -
> > -	if (rw == 0) {
> > -		idx = READ_IO;
> > -	} else {
> > -		if (is_sync)
> > -			idx = WRITE_SYNC_IO;
> > -		else
> > -			idx = WRITE_ASYNC_IO;
> > -	}
> > +	if (page_type >= META_FLUSH)
> > +		page_type = META;
> >   	spin_lock_irqsave(&sbi->iostat_lat_lock, flags);
> > -	io_lat->sum_lat[idx][iotype] += ts_diff;
> > -	io_lat->bio_cnt[idx][iotype]++;
> > -	if (ts_diff > io_lat->peak_lat[idx][iotype])
> > -		io_lat->peak_lat[idx][iotype] = ts_diff;
> > +	io_lat->sum_lat[type][page_type] += ts_diff;
> > +	io_lat->bio_cnt[type][page_type]++;
> > +	if (ts_diff > io_lat->peak_lat[type][page_type])
> > +		io_lat->peak_lat[type][page_type] = ts_diff;
> >   	spin_unlock_irqrestore(&sbi->iostat_lat_lock, flags);
> >   }
> > -void iostat_update_and_unbind_ctx(struct bio *bio, int rw)
> > +void iostat_update_and_unbind_ctx(struct bio *bio, enum iostat_lat_type type)
> >   {
> >   	struct bio_iostat_ctx *iostat_ctx = bio->bi_private;
> > -	bool is_sync = bio->bi_opf & REQ_SYNC;
> > -	if (rw == 0)
> > +	if (type == READ_IO)
> >   		bio->bi_private = iostat_ctx->post_read_ctx;
> >   	else
> >   		bio->bi_private = iostat_ctx->sbi;
> > -	__update_iostat_latency(iostat_ctx, rw, is_sync);
> > +	__update_iostat_latency(iostat_ctx, type);
> >   	mempool_free(iostat_ctx, bio_iostat_ctx_pool);
> >   }
> > diff --git a/fs/f2fs/iostat.h b/fs/f2fs/iostat.h
> > index 2c048307b6e0..1f827a2fe6b2 100644
> > --- a/fs/f2fs/iostat.h
> > +++ b/fs/f2fs/iostat.h
> > @@ -8,20 +8,21 @@
> >   struct bio_post_read_ctx;
> > +enum iostat_lat_type {
> > +	READ_IO = 0,
> > +	WRITE_SYNC_IO,
> > +	WRITE_ASYNC_IO,
> > +	MAX_IO_TYPE,
> > +};
> > +
> >   #ifdef CONFIG_F2FS_IOSTAT
> > +#define NUM_PREALLOC_IOSTAT_CTXS	128
> >   #define DEFAULT_IOSTAT_PERIOD_MS	3000
> >   #define MIN_IOSTAT_PERIOD_MS		100
> >   /* maximum period of iostat tracing is 1 day */
> >   #define MAX_IOSTAT_PERIOD_MS		8640000
> > -enum {
> > -	READ_IO,
> > -	WRITE_SYNC_IO,
> > -	WRITE_ASYNC_IO,
> > -	MAX_IO_TYPE,
> > -};
> > -
> >   struct iostat_lat_info {
> >   	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 */
> > @@ -57,7 +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_update_and_unbind_ctx(struct bio *bio, int rw);
> > +extern void iostat_update_and_unbind_ctx(struct bio *bio, enum iostat_lat_type type);
> >   extern void iostat_alloc_and_bind_ctx(struct f2fs_sb_info *sbi,
> >   		struct bio *bio, struct bio_post_read_ctx *ctx);
> >   extern int f2fs_init_iostat_processing(void);
> > @@ -67,7 +68,7 @@ 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_update_and_unbind_ctx(struct bio *bio, int rw) {}
> > +static inline void iostat_update_and_unbind_ctx(struct bio *bio, enum iostat_lat_type type) {}
> >   static inline void iostat_alloc_and_bind_ctx(struct f2fs_sb_info *sbi,
> >   		struct bio *bio, struct bio_post_read_ctx *ctx) {}
> >   static inline void iostat_update_submit_ctx(struct bio *bio,