PROBE::IOBLOCK_TRACE(3stap) IO Scheduler and block IO Taps PROBE::IOBLOCK_TRACE(3stap)NAME
probe::ioblock_trace.request - Fires just as a generic block I/O request is created for a bio.
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
The process makes block I/O request
SystemTap Tapset Reference June 2014 PROBE::IOBLOCK_TRACE(3stap)
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