include/linux/part_stat.h

Source file repositories/reference/linux-study-clean/include/linux/part_stat.h

File Facts

System
Linux kernel
Corpus path
include/linux/part_stat.h
Extension
.h
Size
2497 bytes
Lines
85
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

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:
 *
 * part_stat_{add|sub|inc|dec}() modify the stat counters and should
 * be called between part_stat_lock() and part_stat_unlock().
 *
 * part_stat_read() can be called at any time.
 */
#define part_stat_lock()	preempt_disable()
#define part_stat_unlock()	preempt_enable()

#define part_stat_get_cpu(part, field, cpu)				\
	(per_cpu_ptr((part)->bd_stats, (cpu))->field)

#define part_stat_get(part, field)					\
	part_stat_get_cpu(part, field, smp_processor_id())

#define part_stat_read(part, field)					\
({									\
	TYPEOF_UNQUAL((part)->bd_stats->field) res = 0;			\
	unsigned int _cpu;						\
	for_each_possible_cpu(_cpu)					\
		res += per_cpu_ptr((part)->bd_stats, _cpu)->field; \
	res;								\
})

static inline void part_stat_set_all(struct block_device *part, int value)
{
	int i;

	for_each_possible_cpu(i)
		memset(per_cpu_ptr(part->bd_stats, i), value,
				sizeof(struct disk_stats));
}

#define part_stat_read_accum(part, field)				\
	(part_stat_read(part, field[STAT_READ]) +			\
	 part_stat_read(part, field[STAT_WRITE]) +			\
	 part_stat_read(part, field[STAT_DISCARD]))

#define __part_stat_add(part, field, addnd)				\
	__this_cpu_add((part)->bd_stats->field, addnd)

#define part_stat_add(part, field, addnd)	do {			\
	__part_stat_add((part), field, addnd);				\
	if (bdev_is_partition(part))					\
		__part_stat_add(bdev_whole(part), field, addnd);	\
} while (0)

#define part_stat_dec(part, field)					\
	part_stat_add(part, field, -1)
#define part_stat_inc(part, field)					\
	part_stat_add(part, field, 1)
#define part_stat_sub(part, field, subnd)				\
	part_stat_add(part, field, -subnd)

#define part_stat_local_dec(part, field)				\
	local_dec(&(part_stat_get(part, field)))
#define part_stat_local_inc(part, field)				\
	local_inc(&(part_stat_get(part, field)))
#define part_stat_local_read(part, field)				\
	local_read(&(part_stat_get(part, field)))
#define part_stat_local_read_cpu(part, field, cpu)			\
	local_read(&(part_stat_get_cpu(part, field, cpu)))

unsigned int bdev_count_inflight(struct block_device *part);

#endif /* _LINUX_PART_STAT_H */

Annotation

Implementation Notes