Scroll to navigation

PROBE::IOBLOCK_TRACE(3stap) IO Scheduler and block IO Taps PROBE::IOBLOCK_TRACE(3stap)

NAME

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

SYNOPSIS

ioblock_trace.request

VALUES

bdev
target block device
bytes_done
number of bytes transferred
ino
i-node number of the mapped file
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
q
request queue on which this bio was queued.
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
size
total size in bytes
p_start_sect
points to the start sector of the partition structure of the device
name
name of the probe point
vcnt
bio vector count which represents number of array element (page, offset, length) which make up this I/O request
sector
beginning sector for the entire bio
devname
block device name
bdev_contains
points to the device object which contains the partition (when bio structure represents a partition)

CONTEXT

The process makes block I/O request

SEE ALSO0

tapset::ioblock(3stap)
March 2016 SystemTap Tapset Reference