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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

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

ino

i-node number of the mapped file

opf

operations and flags

vcnt

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

devname

block device name

name

name of the probe point

bdev

target block device

hw_segments

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

sector

beginning sector for the entire bio

idx

offset into the bio vector array

phys_segments

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

p_start_sect

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

rw

binary trace for read/write request

size

total size in bytes

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

CONTEXT

The process makes block I/O request

SEE ALSO0

tapset::ioblock(3stap)
May 2021 SystemTap Tapset Reference