md/raid1: make sequential read detection per disk based (be4d3280) · Commits · 戴 / test

drivers/md/raid1.c

+7 −28

Original line number	Diff line number	Diff line
		@@ -497,9 +497,8 @@ static int read_balance(struct r1conf conf, struct r1bio r1_bio, int *max_sect
		const sector_t this_sector = r1_bio->sector;
		int sectors;
		int best_good_sectors;
		int start_disk;
		int best_disk;
		int i;
		int disk;
		sector_t best_dist;
		struct md_rdev *rdev;
		int choose_first;
		@@ -517,23 +516,16 @@ static int read_balance(struct r1conf conf, struct r1bio r1_bio, int *max_sect
		best_good_sectors = 0;

		if (conf->mddev->recovery_cp < MaxSector &&
		(this_sector + sectors >= conf->next_resync)) {
		(this_sector + sectors >= conf->next_resync))
		choose_first = 1;
		start_disk = 0;
		} else {
		else
		choose_first = 0;
		start_disk = conf->last_used;
		}

		for (i = 0 ; i < conf->raid_disks * 2 ; i++) {
		for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
		sector_t dist;
		sector_t first_bad;
		int bad_sectors;

		int disk = start_disk + i;
		if (disk >= conf->raid_disks * 2)
		disk -= conf->raid_disks * 2;

		rdev = rcu_dereference(conf->mirrors[disk].rdev);
		if (r1_bio->bios[disk] == IO_BLOCKED
		\|\| rdev == NULL
		@@ -594,7 +586,7 @@ static int read_balance(struct r1conf conf, struct r1bio r1_bio, int *max_sect
		dist = abs(this_sector - conf->mirrors[disk].head_position);
		if (choose_first
		/* Don't change to another disk for sequential reads */
		\|\| conf->next_seq_sect == this_sector
		\|\| conf->mirrors[disk].next_seq_sect == this_sector
		\|\| dist == 0
		/* If device is idle, use it */
		\|\| atomic_read(&rdev->nr_pending) == 0) {
		@@ -620,8 +612,7 @@ static int read_balance(struct r1conf conf, struct r1bio r1_bio, int *max_sect
		goto retry;
		}
		sectors = best_good_sectors;
		conf->next_seq_sect = this_sector + sectors;
		conf->last_used = best_disk;
		conf->mirrors[best_disk].next_seq_sect = this_sector + sectors;
		}
		rcu_read_unlock();
		*max_sectors = sectors;
		@@ -2599,7 +2590,6 @@ static struct r1conf setup_conf(struct mddev mddev)
		conf->recovery_disabled = mddev->recovery_disabled - 1;

		err = -EIO;
		conf->last_used = -1;
		for (i = 0; i < conf->raid_disks * 2; i++) {

		disk = conf->mirrors + i;
		@@ -2625,19 +2615,9 @@ static struct r1conf setup_conf(struct mddev mddev)
		if (disk->rdev &&
		(disk->rdev->saved_raid_disk < 0))
		conf->fullsync = 1;
		} else if (conf->last_used < 0)
		/*
		* The first working device is used as a
		* starting point to read balancing.
		*/
		conf->last_used = i;
		}

		if (conf->last_used < 0) {
		printk(KERN_ERR "md/raid1:%s: no operational mirrors\n",
		mdname(mddev));
		goto abort;
		}

		err = -ENOMEM;
		conf->thread = md_register_thread(raid1d, mddev, "raid1");
		if (!conf->thread) {
		@@ -2894,7 +2874,6 @@ static int raid1_reshape(struct mddev *mddev)
		conf->raid_disks = mddev->raid_disks = raid_disks;
		mddev->delta_disks = 0;

		conf->last_used = 0; /* just make sure it is in-range */
		lower_barrier(conf);

		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);

drivers/md/raid1.h

+5 −6

Original line number	Diff line number	Diff line
		@@ -4,6 +4,11 @@
		struct raid1_info {
		struct md_rdev *rdev;
		sector_t head_position;

		/* When choose the best device for a read (read_balance())
		* we try to keep sequential reads one the same device
		*/
		sector_t next_seq_sect;
		};

		/*
		@@ -29,12 +34,6 @@ struct r1conf {
		*/
		int raid_disks;

		/* When choose the best device for a read (read_balance())
		* we try to keep sequential reads one the same device
		* using 'last_used' and 'next_seq_sect'
		*/
		int last_used;
		sector_t next_seq_sect;
		/* During resync, read_balancing is only allowed on the part
		* of the array that has been resynced. 'next_resync' tells us
		* where that is.

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