#include <sys/zfs_context.h>
#include <sys/vdev_impl.h>
#include <sys/zio.h>
#include <sys/avl.h>

Include dependency graph for vdev_queue.c:

Defines
#define	IO_SPAN(fio, lio) ((lio)->io_offset + (lio)->io_size - (fio)->io_offset)
	Compute the range spanned by two i/os, which is the endpoint of the last (lio->io_offset + lio->io_size) minus start of the first (fio->io_offset).
#define	IO_GAP(fio, lio) (-IO_SPAN(lio, fio))
Functions
	SYSCTL_DECL (_vfs_zfs_vdev)
	TUNABLE_INT ("vfs.zfs.vdev.max_pending",&zfs_vdev_max_pending)
	SYSCTL_INT (_vfs_zfs_vdev, OID_AUTO, max_pending, CTLFLAG_RW,&zfs_vdev_max_pending, 0,"Maximum I/O requests pending on each device")
	TUNABLE_INT ("vfs.zfs.vdev.min_pending",&zfs_vdev_min_pending)
	SYSCTL_INT (_vfs_zfs_vdev, OID_AUTO, min_pending, CTLFLAG_RW,&zfs_vdev_min_pending, 0,"Initial number of I/O requests pending to each device")
	TUNABLE_INT ("vfs.zfs.vdev.time_shift",&zfs_vdev_time_shift)
	SYSCTL_INT (_vfs_zfs_vdev, OID_AUTO, time_shift, CTLFLAG_RW,&zfs_vdev_time_shift, 0,"Used for calculating I/O request deadline")
	TUNABLE_INT ("vfs.zfs.vdev.ramp_rate",&zfs_vdev_ramp_rate)
	SYSCTL_INT (_vfs_zfs_vdev, OID_AUTO, ramp_rate, CTLFLAG_RW,&zfs_vdev_ramp_rate, 0,"Exponential I/O issue ramp-up rate")
	TUNABLE_INT ("vfs.zfs.vdev.aggregation_limit",&zfs_vdev_aggregation_limit)
	SYSCTL_INT (_vfs_zfs_vdev, OID_AUTO, aggregation_limit, CTLFLAG_RW,&zfs_vdev_aggregation_limit, 0,"I/O requests are aggregated up to this size")
	TUNABLE_INT ("vfs.zfs.vdev.read_gap_limit",&zfs_vdev_read_gap_limit)
	SYSCTL_INT (_vfs_zfs_vdev, OID_AUTO, read_gap_limit, CTLFLAG_RW,&zfs_vdev_read_gap_limit, 0,"Acceptable gap between two reads being aggregated")
	TUNABLE_INT ("vfs.zfs.vdev.write_gap_limit",&zfs_vdev_write_gap_limit)
	SYSCTL_INT (_vfs_zfs_vdev, OID_AUTO, write_gap_limit, CTLFLAG_RW,&zfs_vdev_write_gap_limit, 0,"Acceptable gap between two writes being aggregated")
int	vdev_queue_deadline_compare (const void x1, const void x2)
	Virtual device vector for disk I/O scheduling.
int	vdev_queue_offset_compare (const void x1, const void x2)
void	vdev_queue_init (vdev_t *vd)
void	vdev_queue_fini (vdev_t *vd)
static void	vdev_queue_io_add (vdev_queue_t vq, zio_t zio)
static void	vdev_queue_io_remove (vdev_queue_t vq, zio_t zio)
static void	vdev_queue_agg_io_done (zio_t *aio)
static zio_t *	vdev_queue_io_to_issue (vdev_queue_t *vq, uint64_t pending_limit)
zio_t *	vdev_queue_io (zio_t *zio)
void	vdev_queue_io_done (zio_t *zio)
Variables
int	zfs_vdev_max_pending = 10
	The maximum number of i/os concurrently pending to each device.
int	zfs_vdev_min_pending = 4
	The initial number of i/os pending to each device (before it starts ramping up to max_pending).
int	zfs_vdev_time_shift = 6
	deadline = pri + ddi_get_lbolt64() >> time_shift)
int	zfs_vdev_ramp_rate = 2
	exponential I/O issue ramp-up rate
int	zfs_vdev_aggregation_limit = SPA_MAXBLOCKSIZE
	To reduce IOPs, we aggregate small adjacent I/Os into one large I/O.
int	zfs_vdev_read_gap_limit = 32 << 10
int	zfs_vdev_write_gap_limit = 4 << 10

Define Documentation

#define IO_GAP	(	fio,
		lio
	)	(-IO_SPAN(lio, fio))

Definition at line 204 of file vdev_queue.c.

#define IO_SPAN	(	fio,
		lio
	)	((lio)->io_offset + (lio)->io_size - (fio)->io_offset)

Compute the range spanned by two i/os, which is the endpoint of the last (lio->io_offset + lio->io_size) minus start of the first (fio->io_offset).

Conveniently, the gap between fio and lio is given by -IO_SPAN(lio, fio); thus fio and lio are adjacent if and only if IO_SPAN(lio, fio) == 0.

Definition at line 203 of file vdev_queue.c.

Function Documentation

SYSCTL_DECL ( _vfs_zfs_vdev )

SYSCTL_INT	(	_vfs_zfs_vdev	,
		OID_AUTO	,
		min_pending	,
		CTLFLAG_RW	,
		&	zfs_vdev_min_pending,
		0	,
		"Initial number of I/O requests pending to each device"
	)

SYSCTL_INT	(	_vfs_zfs_vdev	,
		OID_AUTO	,
		ramp_rate	,
		CTLFLAG_RW	,
		&	zfs_vdev_ramp_rate,
		0	,
		"Exponential I/O issue ramp-up rate"
	)

SYSCTL_INT	(	_vfs_zfs_vdev	,
		OID_AUTO	,
		aggregation_limit	,
		CTLFLAG_RW	,
		&	zfs_vdev_aggregation_limit,
		0	,
		"I/O requests are aggregated up to this size"
	)

SYSCTL_INT	(	_vfs_zfs_vdev	,
		OID_AUTO	,
		max_pending	,
		CTLFLAG_RW	,
		&	zfs_vdev_max_pending,
		0	,
		"Maximum I/O requests pending on each device"
	)

SYSCTL_INT	(	_vfs_zfs_vdev	,
		OID_AUTO	,
		read_gap_limit	,
		CTLFLAG_RW	,
		&	zfs_vdev_read_gap_limit,
		0	,
		"Acceptable gap between two reads being aggregated"
	)

SYSCTL_INT	(	_vfs_zfs_vdev	,
		OID_AUTO	,
		time_shift	,
		CTLFLAG_RW	,
		&	zfs_vdev_time_shift,
		0	,
		"Used for calculating I/O request deadline"
	)

SYSCTL_INT	(	_vfs_zfs_vdev	,
		OID_AUTO	,
		write_gap_limit	,
		CTLFLAG_RW	,
		&	zfs_vdev_write_gap_limit,
		0	,
		"Acceptable gap between two writes being aggregated"
	)

TUNABLE_INT	(	"vfs.zfs.vdev.ramp_rate"	,
		&	zfs_vdev_ramp_rate
	)

TUNABLE_INT	(	"vfs.zfs.vdev.min_pending"	,
		&	zfs_vdev_min_pending
	)

TUNABLE_INT	(	"vfs.zfs.vdev.aggregation_limit"	,
		&	zfs_vdev_aggregation_limit
	)

TUNABLE_INT	(	"vfs.zfs.vdev.max_pending"	,
		&	zfs_vdev_max_pending
	)

TUNABLE_INT	(	"vfs.zfs.vdev.read_gap_limit"	,
		&	zfs_vdev_read_gap_limit
	)

TUNABLE_INT	(	"vfs.zfs.vdev.time_shift"	,
		&	zfs_vdev_time_shift
	)

TUNABLE_INT	(	"vfs.zfs.vdev.write_gap_limit"	,
		&	zfs_vdev_write_gap_limit
	)

static void vdev_queue_agg_io_done ( zio_t * aio ) [static]

Definition at line 185 of file vdev_queue.c.

int vdev_queue_deadline_compare	(	const void *	x1,
		const void *	x2
	)

Virtual device vector for disk I/O scheduling.

Definition at line 95 of file vdev_queue.c.

void vdev_queue_fini ( vdev_t * vd )

Definition at line 158 of file vdev_queue.c.

void vdev_queue_init ( vdev_t * vd )

Definition at line 138 of file vdev_queue.c.

zio_t* vdev_queue_io ( zio_t * zio )

Definition at line 375 of file vdev_queue.c.

static void vdev_queue_io_add	(	vdev_queue_t *	vq,
		zio_t *	zio
	)		`[static]`

Definition at line 171 of file vdev_queue.c.

void vdev_queue_io_done ( zio_t * zio )

Definition at line 415 of file vdev_queue.c.

static void vdev_queue_io_remove	(	vdev_queue_t *	vq,
		zio_t *	zio
	)		`[static]`

Definition at line 178 of file vdev_queue.c.

static zio_t* vdev_queue_io_to_issue	(	vdev_queue_t *	vq,
		uint64_t	pending_limit
	)		`[static]`

Definition at line 207 of file vdev_queue.c.

int vdev_queue_offset_compare	(	const void *	x1,
		const void *	x2
	)

Definition at line 119 of file vdev_queue.c.

vdev_queue.c File Reference

Defines

Functions

Variables

Define Documentation

Function Documentation