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PROBE::IOBLOCK.REQ(3stap) IO Scheduler and block IO Taps PROBE::IOBLOCK.REQ(3stap)

NAME

probe::ioblock.request - Fires whenever making a generic block I/O request.

SYNOPSIS

ioblock.request

VALUES

hw_segments
number of segments after physical and DMA remapping hardware coalescing is performed

opf

operations and flags

idx

offset into the bio vector array

rw

binary trace for read/write request

p_start_sect

points to the start sector of the partition structure of the device

bdev

target block device

size

total size in bytes

phys_segments

number of segments in this bio after physical address coalescing is performed

devname

block device name

vcnt

bio vector count which represents number of array element (page, offset, length) which make up this I/O request

ino

i-node number of the mapped file

flags

see below BIO_UPTODATE 0 ok after I/O completion BIO_RW_BLOCK 1 RW_AHEAD set, and read/write would block BIO_EOF 2 out-out-bounds error BIO_SEG_VALID 3 nr_hw_seg valid BIO_CLONED 4 doesn't own data BIO_BOUNCED 5 bio is a bounce bio BIO_USER_MAPPED 6 contains user pages BIO_EOPNOTSUPP 7 not supported

name

name of the probe point

bdev_contains

points to the device object which contains the partition (when bio structure represents a partition)

sector

beginning sector for the entire bio

CONTEXT

The process makes block I/O request

SEE ALSO0

tapset::ioblock(3stap)
October 2018 SystemTap Tapset Reference