Commit 49f357a2 authored by NeilBrown's avatar NeilBrown
Browse files

md: raid0: remove ->sectors from the strip_zone structure. 



storing ->sectors is redundant as is can be computed from the
difference  z->zone_end - (z-1)->zone_end

The one place where it is used, it is just as efficient to use
a zone_end value instead.

And removing it makes strip_zone smaller, so they array of these that
is searched on every request has a better chance to say in cache.

So discard the field and get the value from elsewhere.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent fb5ab4b5

drivers/md/raid0.c

+19 −14
Original line number Diff line number Diff line
@@ -55,7 +55,7 @@ static int raid0_congested(void *data, int bits) 
static int create_strip_zones(mddev_t *mddev)

{

	int i, c, j, err;

	sector_t curr_zone_end;

	sector_t curr_zone_end, sectors;

	mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev;

	struct strip_zone *zone;

	int cnt;
@@ -153,10 +153,9 @@ static int create_strip_zones(mddev_t *mddev) 
		goto abort;

	}

	zone->nb_dev = cnt;

	zone->sectors = smallest->sectors * cnt;

	zone->zone_end = zone->sectors;

	zone->zone_end = smallest->sectors * cnt;



	curr_zone_end = zone->sectors;

	curr_zone_end = zone->zone_end;



	/* now do the other zones */

	for (i = 1; i < conf->nr_strip_zones; i++)
@@ -189,11 +188,11 @@ static int create_strip_zones(mddev_t *mddev) 
		}



		zone->nb_dev = c;

		zone->sectors = (smallest->sectors - zone->dev_start) * c;

		sectors = (smallest->sectors - zone->dev_start) * c;

		printk(KERN_INFO "raid0: zone->nb_dev: %d, sectors: %llu\n",

			zone->nb_dev, (unsigned long long)zone->sectors);

			zone->nb_dev, (unsigned long long)sectors);



		curr_zone_end += zone->sectors;

		curr_zone_end += sectors;

		zone->zone_end = curr_zone_end;



		printk(KERN_INFO "raid0: current zone start: %llu\n",
@@ -310,16 +309,22 @@ static int raid0_stop(mddev_t *mddev) 
	return 0;

}



/* Find the zone which holds a particular offset */

/* Find the zone which holds a particular offset

 * Update *sectorp to be an offset in that zone

 */

static struct strip_zone *find_zone(struct raid0_private_data *conf,

		sector_t sector)

				    sector_t *sectorp)

{

	int i;

	struct strip_zone *z = conf->strip_zone;

	sector_t sector = *sectorp;



	for (i = 0; i < conf->nr_strip_zones; i++)

		if (sector < z[i].zone_end)

		if (sector < z[i].zone_end) {

			if (i)

				*sectorp = sector - z[i-1].zone_end;

			return z + i;

		}

	BUG();

}
@@ -331,7 +336,7 @@ static int raid0_make_request (struct request_queue *q, struct bio *bio) 
	struct strip_zone *zone;

	mdk_rdev_t *tmp_dev;

	sector_t chunk;

	sector_t sector, rsect;

	sector_t sector, rsect, sector_offset;

	const int rw = bio_data_dir(bio);

	int cpu;
@@ -368,11 +373,11 @@ static int raid0_make_request (struct request_queue *q, struct bio *bio) 
		bio_pair_release(bp);

		return 0;

	}

	zone = find_zone(conf, sector);

	sector_offset = sector;

	zone = find_zone(conf, &sector_offset);

	sect_in_chunk = bio->bi_sector & (chunk_sects - 1);

	{

		sector_t x = (zone->sectors + sector - zone->zone_end)

				>> chunksect_bits;

		sector_t x = sector_offset >> chunksect_bits;



		sector_div(x, zone->nb_dev);

		chunk = x;

drivers/md/raid0.h

+0 −1
Original line number Diff line number Diff line
@@ -5,7 +5,6 @@ struct strip_zone 
{

	sector_t zone_end;	/* Start of the next zone (in sectors) */

	sector_t dev_start;	/* Zone offset in real dev (in sectors) */

	sector_t sectors;	/* Zone size in sectors */

	int nb_dev;		/* # of devices attached to the zone */

	mdk_rdev_t **dev;	/* Devices attached to the zone */

};

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