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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

phys_segments
number of segments in this bio after physical address coalescing is performed
bdev_contains
points to the device object which contains the partition (when bio structure represents a partition)
devname
block device name
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
sector
beginning sector for the entire bio
p_start_sect
points to the start sector of the partition structure of the device
vcnt
bio vector count which represents number of array element (page, offset, length) which make up this I/O request
name
name of the probe point
rw
binary trace for read/write request
idx
offset into the bio vector array
ino
i-node number of the mapped file
bdev
target block device
hw_segments
number of segments after physical and DMA remapping hardware coalescing is performed

CONTEXT

The process makes block I/O request

SEE ALSO0

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