| PROBE::IOBLOCK_TRACE(3stap) | IO Scheduler and block IO Taps | PROBE::IOBLOCK_TRACE(3stap) |
NAME¶
probe::ioblock_trace.bounce - Fires whenever a buffer bounce is needed for at least one page of a block IO request.
SYNOPSIS¶
ioblock_trace.bounce
VALUES¶
name
name of the probe point
rw
binary trace for read/write request
idx
offset into the bio vector array phys_segments -
number of segments in this bio after physical address coalescing is
performed.
opf
operations and flags
vcnt
bio vector count which represents number of array element
(page, offset, length) which makes up this I/O request
bdev_contains
points to the device object which contains the partition
(when bio structure represents a partition)
sector
beginning sector for the entire bio
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
bdev
target block device
ino
i-node number of the mapped file
p_start_sect
points to the start sector of the partition structure of
the device
q
request queue on which this bio was queued.
bytes_done
number of bytes transferred
devname
device for which a buffer bounce was needed.
size
total size in bytes
CONTEXT¶
The process creating a block IO request.
SEE ALSO0¶
tapset::ioblock(3stap)
| April 2025 | SystemTap Tapset Reference |