[BLOCK] Unify the seperate read/write io stat fields into arrays

Instead of having ->read_sectors and ->write_sectors, combine the two
into ->sectors[2] and similar for the other fields. This saves a branch
several places in the io path, since we don't have to care for what the
actual io direction is. On my x86-64 box, that's 200 bytes less text in
just the core (not counting the various drivers).
Signed-off-by: Jens Axboe <axboe@suse.de>

drivers/block/genhd.c

@@ -391,13 +391,12 @@ static ssize_t disk_stats_read(struct gendisk * disk, char *page)
 		"%8u %8u %8llu %8u "
 		"%8u %8u %8u"
 		"\n",
-		disk_stat_read(disk, reads), disk_stat_read(disk, read_merges),
-		(unsigned long long)disk_stat_read(disk, read_sectors),
-		jiffies_to_msecs(disk_stat_read(disk, read_ticks)),
-		disk_stat_read(disk, writes), 
-		disk_stat_read(disk, write_merges),
-		(unsigned long long)disk_stat_read(disk, write_sectors),
-		jiffies_to_msecs(disk_stat_read(disk, write_ticks)),
+		disk_stat_read(disk, ios[0]), disk_stat_read(disk, merges[0]),
+		(unsigned long long)disk_stat_read(disk, sectors[0]),
+		jiffies_to_msecs(disk_stat_read(disk, ticks[0])),
+		disk_stat_read(disk, ios[1]), disk_stat_read(disk, merges[1]),
+		(unsigned long long)disk_stat_read(disk, sectors[1]),
+		jiffies_to_msecs(disk_stat_read(disk, ticks[1])),
 		disk->in_flight,
 		jiffies_to_msecs(disk_stat_read(disk, io_ticks)),
 		jiffies_to_msecs(disk_stat_read(disk, time_in_queue)));
@@ -583,12 +582,12 @@ static int diskstats_show(struct seq_file *s, void *v)
 	preempt_enable();
 	seq_printf(s, "%4d %4d %s %u %u %llu %u %u %u %llu %u %u %u %u\n",
 		gp->major, n + gp->first_minor, disk_name(gp, n, buf),
-		disk_stat_read(gp, reads), disk_stat_read(gp, read_merges),
-		(unsigned long long)disk_stat_read(gp, read_sectors),
-		jiffies_to_msecs(disk_stat_read(gp, read_ticks)),
-		disk_stat_read(gp, writes), disk_stat_read(gp, write_merges),
-		(unsigned long long)disk_stat_read(gp, write_sectors),
-		jiffies_to_msecs(disk_stat_read(gp, write_ticks)),
+		disk_stat_read(gp, ios[0]), disk_stat_read(gp, merges[0]),
+		(unsigned long long)disk_stat_read(gp, sectors[0]),
+		jiffies_to_msecs(disk_stat_read(gp, ticks[0])),
+		disk_stat_read(gp, ios[1]), disk_stat_read(gp, merges[1]),
+		(unsigned long long)disk_stat_read(gp, sectors[1]),
+		jiffies_to_msecs(disk_stat_read(gp, ticks[1])),
 		gp->in_flight,
 		jiffies_to_msecs(disk_stat_read(gp, io_ticks)),
 		jiffies_to_msecs(disk_stat_read(gp, time_in_queue)));
@@ -601,8 +600,8 @@ static int diskstats_show(struct seq_file *s, void *v)
 			seq_printf(s, "%4d %4d %s %u %u %u %u\n",
 				gp->major, n + gp->first_minor + 1,
 				disk_name(gp, n + 1, buf),
-				hd->reads, hd->read_sectors,
-				hd->writes, hd->write_sectors);
+				hd->ios[0], hd->sectors[0],
+				hd->ios[1], hd->sectors[1]);
 	}
  
 	return 0;

drivers/block/ll_rw_blk.c

@@ -2388,10 +2388,7 @@ static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io)
 		return;
 
 	if (!new_io) {
-		if (rw == READ)
-			__disk_stat_inc(rq->rq_disk, read_merges);
-		else
-			__disk_stat_inc(rq->rq_disk, write_merges);
+		__disk_stat_inc(rq->rq_disk, merges[rw]);
 	} else {
 		disk_round_stats(rq->rq_disk);
 		rq->rq_disk->in_flight++;
@@ -2787,17 +2784,11 @@ static inline void blk_partition_remap(struct bio *bio)
 
 	if (bdev != bdev->bd_contains) {
 		struct hd_struct *p = bdev->bd_part;
+		const int rw = bio_data_dir(bio);
+
+		p->sectors[rw] += bio_sectors(bio);
+		p->ios[rw]++;
 
-		switch (bio_data_dir(bio)) {
-		case READ:
-			p->read_sectors += bio_sectors(bio);
-			p->reads++;
-			break;
-		case WRITE:
-			p->write_sectors += bio_sectors(bio);
-			p->writes++;
-			break;
-		}
 		bio->bi_sector += p->start_sect;
 		bio->bi_bdev = bdev->bd_contains;
 	}
@@ -3045,10 +3036,9 @@ static int __end_that_request_first(struct request *req, int uptodate,
 	}
 
 	if (blk_fs_request(req) && req->rq_disk) {
-		if (rq_data_dir(req) == READ)
-			__disk_stat_add(req->rq_disk, read_sectors, nr_bytes >> 9);
-		else
-			__disk_stat_add(req->rq_disk, write_sectors, nr_bytes >> 9);
+		const int rw = rq_data_dir(req);
+
+		__disk_stat_add(req->rq_disk, sectors[rw], nr_bytes >> 9);
 	}
 
 	total_bytes = bio_nbytes = 0;
@@ -3179,16 +3169,10 @@ void end_that_request_last(struct request *req)
 
 	if (disk && blk_fs_request(req)) {
 		unsigned long duration = jiffies - req->start_time;
-		switch (rq_data_dir(req)) {
-		    case WRITE:
-			__disk_stat_inc(disk, writes);
-			__disk_stat_add(disk, write_ticks, duration);
-			break;
-		    case READ:
-			__disk_stat_inc(disk, reads);
-			__disk_stat_add(disk, read_ticks, duration);
-			break;
-		}
+		const int rw = rq_data_dir(req);
+
+		__disk_stat_inc(disk, ios[rw]);
+		__disk_stat_add(disk, ticks[rw], duration);
 		disk_round_stats(disk);
 		disk->in_flight--;
 	}

drivers/md/linear.c

@@ -271,6 +271,7 @@ static int linear_stop (mddev_t *mddev)
 
 static int linear_make_request (request_queue_t *q, struct bio *bio)
 {
+	const int rw = bio_data_dir(bio);
 	mddev_t *mddev = q->queuedata;
 	dev_info_t *tmp_dev;
 	sector_t block;
@@ -280,13 +281,8 @@ static int linear_make_request (request_queue_t *q, struct bio *bio)
 		return 0;
 	}
 
-	if (bio_data_dir(bio)==WRITE) {
-		disk_stat_inc(mddev->gendisk, writes);
-		disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
-	} else {
-		disk_stat_inc(mddev->gendisk, reads);
-		disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
-	}
+	disk_stat_inc(mddev->gendisk, ios[rw]);
+	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
 
 	tmp_dev = which_dev(mddev, bio->bi_sector);
 	block = bio->bi_sector >> 1;

drivers/md/md.c

@@ -3466,8 +3466,8 @@ static int is_mddev_idle(mddev_t *mddev)
 	idle = 1;
 	ITERATE_RDEV(mddev,rdev,tmp) {
 		struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
-		curr_events = disk_stat_read(disk, read_sectors) + 
-				disk_stat_read(disk, write_sectors) - 
+		curr_events = disk_stat_read(disk, sectors[0]) + 
+				disk_stat_read(disk, sectors[1]) - 
 				atomic_read(&disk->sync_io);
 		/* Allow some slack between valud of curr_events and last_events,
 		 * as there are some uninteresting races.

drivers/md/multipath.c

@@ -168,6 +168,7 @@ static int multipath_make_request (request_queue_t *q, struct bio * bio)
 	multipath_conf_t *conf = mddev_to_conf(mddev);
 	struct multipath_bh * mp_bh;
 	struct multipath_info *multipath;
+	const int rw = bio_data_dir(bio);
 
 	if (unlikely(bio_barrier(bio))) {
 		bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
@@ -179,13 +180,8 @@ static int multipath_make_request (request_queue_t *q, struct bio * bio)
 	mp_bh->master_bio = bio;
 	mp_bh->mddev = mddev;
 
-	if (bio_data_dir(bio)==WRITE) {
-		disk_stat_inc(mddev->gendisk, writes);
-		disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
-	} else {
-		disk_stat_inc(mddev->gendisk, reads);
-		disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
-	}
+	disk_stat_inc(mddev->gendisk, ios[rw]);
+	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
 
 	mp_bh->path = multipath_map(conf);
 	if (mp_bh->path < 0) {

drivers/md/raid0.c

@@ -403,19 +403,15 @@ static int raid0_make_request (request_queue_t *q, struct bio *bio)
 	mdk_rdev_t *tmp_dev;
 	unsigned long chunk;
 	sector_t block, rsect;
+	const int rw = bio_data_dir(bio);
 
 	if (unlikely(bio_barrier(bio))) {
 		bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
 		return 0;
 	}
 
-	if (bio_data_dir(bio)==WRITE) {
-		disk_stat_inc(mddev->gendisk, writes);
-		disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
-	} else {
-		disk_stat_inc(mddev->gendisk, reads);
-		disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
-	}
+	disk_stat_inc(mddev->gendisk, ios[rw]);
+	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
 
 	chunk_size = mddev->chunk_size >> 10;
 	chunk_sects = mddev->chunk_size >> 9;

drivers/md/raid1.c

@@ -647,6 +647,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
 	unsigned long flags;
 	struct bio_list bl;
 	struct page **behind_pages = NULL;
+	const int rw = bio_data_dir(bio);
 
 	if (unlikely(bio_barrier(bio))) {
 		bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
@@ -665,13 +666,8 @@ static int make_request(request_queue_t *q, struct bio * bio)
 	conf->nr_pending++;
 	spin_unlock_irq(&conf->resync_lock);
 
-	if (bio_data_dir(bio)==WRITE) {
-		disk_stat_inc(mddev->gendisk, writes);
-		disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
-	} else {
-		disk_stat_inc(mddev->gendisk, reads);
-		disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
-	}
+	disk_stat_inc(mddev->gendisk, ios[rw]);
+	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
 
 	/*
 	 * make_request() can abort the operation when READA is being
@@ -686,7 +682,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
 	r1_bio->mddev = mddev;
 	r1_bio->sector = bio->bi_sector;
 
-	if (bio_data_dir(bio) == READ) {
+	if (rw == READ) {
 		/*
 		 * read balancing logic:
 		 */

drivers/md/raid10.c

@@ -668,6 +668,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
 	struct bio *read_bio;
 	int i;
 	int chunk_sects = conf->chunk_mask + 1;
+	const int rw = bio_data_dir(bio);
 
 	if (unlikely(bio_barrier(bio))) {
 		bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
@@ -718,13 +719,8 @@ static int make_request(request_queue_t *q, struct bio * bio)
 	conf->nr_pending++;
 	spin_unlock_irq(&conf->resync_lock);
 
-	if (bio_data_dir(bio)==WRITE) {
-		disk_stat_inc(mddev->gendisk, writes);
-		disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
-	} else {
-		disk_stat_inc(mddev->gendisk, reads);
-		disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
-	}
+	disk_stat_inc(mddev->gendisk, ios[rw]);
+	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
 
 	r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
 
@@ -734,7 +730,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
 	r10_bio->mddev = mddev;
 	r10_bio->sector = bio->bi_sector;
 
-	if (bio_data_dir(bio) == READ) {
+	if (rw == READ) {
 		/*
 		 * read balancing logic:
 		 */

drivers/md/raid5.c

@@ -1462,6 +1462,7 @@ static int make_request (request_queue_t *q, struct bio * bi)
 	sector_t new_sector;
 	sector_t logical_sector, last_sector;
 	struct stripe_head *sh;
+	const int rw = bio_data_dir(bi);
 
 	if (unlikely(bio_barrier(bi))) {
 		bio_endio(bi, bi->bi_size, -EOPNOTSUPP);
@@ -1470,13 +1471,8 @@ static int make_request (request_queue_t *q, struct bio * bi)
 
 	md_write_start(mddev, bi);
 
-	if (bio_data_dir(bi)==WRITE) {
-		disk_stat_inc(mddev->gendisk, writes);
-		disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bi));
-	} else {
-		disk_stat_inc(mddev->gendisk, reads);
-		disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bi));
-	}
+	disk_stat_inc(mddev->gendisk, ios[rw]);
+	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi));
 
 	logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
 	last_sector = bi->bi_sector + (bi->bi_size>>9);

drivers/md/raid6main.c

@@ -1621,6 +1621,7 @@ static int make_request (request_queue_t *q, struct bio * bi)
 	sector_t new_sector;
 	sector_t logical_sector, last_sector;
 	struct stripe_head *sh;
+	const int rw = bio_data_dir(bi);
 
 	if (unlikely(bio_barrier(bi))) {
 		bio_endio(bi, bi->bi_size, -EOPNOTSUPP);
@@ -1629,13 +1630,8 @@ static int make_request (request_queue_t *q, struct bio * bi)
 
 	md_write_start(mddev, bi);
 
-	if (bio_data_dir(bi)==WRITE) {
-		disk_stat_inc(mddev->gendisk, writes);
-		disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bi));
-	} else {
-		disk_stat_inc(mddev->gendisk, reads);
-		disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bi));
-	}
+	disk_stat_inc(mddev->gendisk, ios[rw]);
+	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi));
 
 	logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
 	last_sector = bi->bi_sector + (bi->bi_size>>9);
@@ -1682,7 +1678,7 @@ static int make_request (request_queue_t *q, struct bio * bi)
 	if (--bi->bi_phys_segments == 0) {
 		int bytes = bi->bi_size;
 
-		if ( bio_data_dir(bi) == WRITE )
+		if (rw == WRITE )
 			md_write_end(mddev);
 		bi->bi_size = 0;
 		bi->bi_end_io(bi, bytes, 0);

fs/partitions/check.c

@@ -246,8 +246,8 @@ static ssize_t part_size_read(struct hd_struct * p, char *page)
 static ssize_t part_stat_read(struct hd_struct * p, char *page)
 {
 	return sprintf(page, "%8u %8llu %8u %8llu\n",
-		       p->reads, (unsigned long long)p->read_sectors,
-		       p->writes, (unsigned long long)p->write_sectors);
+		       p->ios[0], (unsigned long long)p->sectors[0],
+		       p->ios[1], (unsigned long long)p->sectors[1]);
 }
 static struct part_attribute part_attr_uevent = {
 	.attr = {.name = "uevent", .mode = S_IWUSR },
@@ -303,7 +303,8 @@ void delete_partition(struct gendisk *disk, int part)
 	disk->part[part-1] = NULL;
 	p->start_sect = 0;
 	p->nr_sects = 0;
-	p->reads = p->writes = p->read_sectors = p->write_sectors = 0;
+	p->ios[0] = p->ios[1] = 0;
+	p->sectors[0] = p->sectors[1] = 0;
 	devfs_remove("%s/part%d", disk->devfs_name, part);
 	kobject_unregister(&p->kobj);
 }

include/linux/genhd.h

@@ -78,7 +78,7 @@ struct hd_struct {
 	sector_t start_sect;
 	sector_t nr_sects;
 	struct kobject kobj;
-	unsigned reads, read_sectors, writes, write_sectors;
+	unsigned ios[2], sectors[2];
 	int policy, partno;
 };
 
@@ -89,10 +89,10 @@ struct hd_struct {
 #define GENHD_FL_SUPPRESS_PARTITION_INFO	32
 
 struct disk_stats {
-	unsigned read_sectors, write_sectors;
-	unsigned reads, writes;
-	unsigned read_merges, write_merges;
-	unsigned read_ticks, write_ticks;
+	unsigned sectors[2];
+	unsigned ios[2];
+	unsigned merges[2];
+	unsigned ticks[2];
 	unsigned io_ticks;
 	unsigned time_in_queue;
 };