PROBE::IOBLOCK_TRACE(3stIO)Scheduler and block IO TPROBE::IOBLOCK_TRACE(3stap)NAMEprobe::ioblock_trace.request - Fires just as a generic block I/O
request is created for a bio.
SYNOPSIS
ioblock_trace.request
VALUES
None
DESCRIPTION
name - name of the probe point q - request queue on which this bio was
queued. devname - block device name ino - i-node number of the mapped
file bytes_done - number of bytes transferred 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
rw - binary trace for read/write request 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 phys_segments -
number of segments in this bio after physical address coalescing is
performed. size - total size in bytes bdev - target block device
bdev_contains - points to the device object which contains the
partition (when bio structure represents a partition) p_start_sect -
points to the start sector of the partition structure of the device
CONTEXT
The process makes block I/O request
SystemTap Tapset Reference March 2013 PROBE::IOBLOCK_TRACE(3stap)
