| 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¶
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
bytes_done
number of bytes transferred
sector
beginning sector for the entire bio
bdev_contains
points to the device object which contains the partition
(when bio structure represents a partition)
ino
i-node number of the mapped file
vcnt
bio vector count which represents number of array element
(page, offset, length) which makes up this I/O 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
device for which a buffer bounce was needed.
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
CONTEXT¶
The process creating a block IO request.
SEE ALSO0¶
tapset::ioblock(3stap)
| October 2018 | SystemTap Tapset Reference |