DOKK / manpages / debian 10 / systemtap-doc / probe::ioblock_trace.request.3stap.en
PROBE::IOBLOCK_TRACE(3stap) IO Scheduler and block IO Taps PROBE::IOBLOCK_TRACE(3stap)

probe::ioblock_trace.request - Fires just as a generic block I/O request is created for a bio.

ioblock_trace.request 

bdev

target block device

p_start_sect

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

size

total size in bytes

devname

block device name

opf

operations and flags

q

request queue on which this bio was queued.

idx

offset into the bio vector array phys_segments - number of segments in this bio after physical address coalescing is performed.

rw

binary trace for read/write request

bytes_done

number of bytes transferred

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

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

The process makes block I/O request

tapset::ioblock(3stap)

October 2018 SystemTap Tapset Reference