Commit 58d4f14f authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: always use a percpu variable for disk stats 



percpu variables have a perfectly fine working stub implementation
for UP kernels, so use that.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 9123bf6f

block/blk.h

+1 −1
Original line number Diff line number Diff line
@@ -378,7 +378,7 @@ static inline void hd_struct_put(struct hd_struct *part) 


static inline void hd_free_part(struct hd_struct *part)

{

	free_part_stats(part);

	free_percpu(part->dkstats);

	kfree(part->info);

	percpu_ref_exit(&part->ref);

}

block/genhd.c

+3 −9
Original line number Diff line number Diff line
@@ -92,7 +92,6 @@ const char *bdevname(struct block_device *bdev, char *buf) 
}

EXPORT_SYMBOL(bdevname);



#ifdef CONFIG_SMP

static void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat)

{

	int cpu;
@@ -112,12 +111,6 @@ static void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat) 
		stat->io_ticks += ptr->io_ticks;

	}

}

#else /* CONFIG_SMP */

static void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat)

{

	memcpy(stat, &part->dkstats, sizeof(struct disk_stats));

}

#endif /* CONFIG_SMP */



static unsigned int part_in_flight(struct request_queue *q,

		struct hd_struct *part)
@@ -1688,14 +1681,15 @@ struct gendisk *__alloc_disk_node(int minors, int node_id) 


	disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);

	if (disk) {

		if (!init_part_stats(&disk->part0)) {

		disk->part0.dkstats = alloc_percpu(struct disk_stats);

		if (!disk->part0.dkstats) {

			kfree(disk);

			return NULL;

		}

		init_rwsem(&disk->lookup_sem);

		disk->node_id = node_id;

		if (disk_expand_part_tbl(disk, 0)) {

			free_part_stats(&disk->part0);

			free_percpu(disk->part0.dkstats);

			kfree(disk);

			return NULL;

		}

block/partitions/core.c

+3 −2
Original line number Diff line number Diff line
@@ -387,7 +387,8 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno, 
	if (!p)

		return ERR_PTR(-EBUSY);



	if (!init_part_stats(p)) {

	p->dkstats = alloc_percpu(struct disk_stats);

	if (!p->dkstats) {

		err = -ENOMEM;

		goto out_free;

	}
@@ -468,7 +469,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno, 
out_free_info:

	kfree(p->info);

out_free_stats:

	free_part_stats(p);

	free_percpu(p->dkstats);

out_free:

	kfree(p);

	return ERR_PTR(err);

include/linux/genhd.h

+0 −13
Original line number Diff line number Diff line
@@ -39,15 +39,6 @@ extern struct class block_class; 
#include <linux/fs.h>

#include <linux/workqueue.h>



struct disk_stats {

	u64 nsecs[NR_STAT_GROUPS];

	unsigned long sectors[NR_STAT_GROUPS];

	unsigned long ios[NR_STAT_GROUPS];

	unsigned long merges[NR_STAT_GROUPS];

	unsigned long io_ticks;

	local_t in_flight[2];

};



#define PARTITION_META_INFO_VOLNAMELTH	64

/*

 * Enough for the string representation of any kind of UUID plus NULL.
@@ -72,11 +63,7 @@ struct hd_struct { 
	seqcount_t nr_sects_seq;

#endif

	unsigned long stamp;

#ifdef	CONFIG_SMP

	struct disk_stats __percpu *dkstats;

#else

	struct disk_stats dkstats;

#endif

	struct percpu_ref ref;



	sector_t alignment_offset;

include/linux/part_stat.h

+11 −44
Original line number Diff line number Diff line
@@ -4,19 +4,23 @@ 


#include <linux/genhd.h>



struct disk_stats {

	u64 nsecs[NR_STAT_GROUPS];

	unsigned long sectors[NR_STAT_GROUPS];

	unsigned long ios[NR_STAT_GROUPS];

	unsigned long merges[NR_STAT_GROUPS];

	unsigned long io_ticks;

	local_t in_flight[2];

};



/*

 * Macros to operate on percpu disk statistics:

 *

 * {disk|part|all}_stat_{add|sub|inc|dec}() modify the stat counters

 * and should be called between disk_stat_lock() and

 * disk_stat_unlock().

 * {disk|part|all}_stat_{add|sub|inc|dec}() modify the stat counters and should

 * be called between disk_stat_lock() and disk_stat_unlock().

 *

 * part_stat_read() can be called at any time.

 *

 * part_stat_{add|set_all}() and {init|free}_part_stats are for

 * internal use only.

 */

#ifdef	CONFIG_SMP

#define part_stat_lock()	({ rcu_read_lock(); get_cpu(); })

#define part_stat_unlock()	do { put_cpu(); rcu_read_unlock(); } while (0)
@@ -44,43 +48,6 @@ static inline void part_stat_set_all(struct hd_struct *part, int value) 
				sizeof(struct disk_stats));

}



static inline int init_part_stats(struct hd_struct *part)

{

	part->dkstats = alloc_percpu(struct disk_stats);

	if (!part->dkstats)

		return 0;

	return 1;

}



static inline void free_part_stats(struct hd_struct *part)

{

	free_percpu(part->dkstats);

}



#else /* !CONFIG_SMP */

#define part_stat_lock()	({ rcu_read_lock(); 0; })

#define part_stat_unlock()	rcu_read_unlock()



#define part_stat_get(part, field)		((part)->dkstats.field)

#define part_stat_get_cpu(part, field, cpu)	part_stat_get(part, field)

#define part_stat_read(part, field)		part_stat_get(part, field)



static inline void part_stat_set_all(struct hd_struct *part, int value)

{

	memset(&part->dkstats, value, sizeof(struct disk_stats));

}



static inline int init_part_stats(struct hd_struct *part)

{

	return 1;

}



static inline void free_part_stats(struct hd_struct *part)

{

}



#endif /* CONFIG_SMP */



#define part_stat_read_accum(part, field)				\

	(part_stat_read(part, field[STAT_READ]) +			\

	 part_stat_read(part, field[STAT_WRITE]) +			\

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