| 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¶
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
devname
block device name
phys_segments
number of segments in this bio after physical address
coalescing is performed
bdev
target block device
sector
beginning sector for the entire bio
name
name of the probe point
size
total size in bytes
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
idx
offset into the bio vector array
hw_segments
number of segments after physical and DMA remapping
hardware coalescing is performed
ino
i-node number of the mapped file
bdev_contains
points to the device object which contains the partition
(when bio structure represents a partition)
rw
binary trace for read/write request
CONTEXT¶
The process makes block I/O request
SEE ALSO0¶
tapset::ioblock(3stap)
| June 2018 | SystemTap Tapset Reference |