Section: IO Scheduler and block IO Taps (3stap)
Updated: August 2015
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probe::ioblock_trace.request - Fires just as a generic block I/O request is created for a bio.
binary trace for read/write request
beginning sector for the entire bio
block device name
offset into the bio vector array
- number of segments in this bio after physical address coalescing is performed.
points to the start sector of the partition structure of the device
target block device
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
request queue on which this bio was queued.
number of bytes transferred
bio vector count which represents number of array element (page, offset, length) which make up this I/O request
i-node number of the mapped file
total size in bytes
name of the probe point
points to the device object which contains the partition (when bio structure represents a partition)
The process makes block I/O request
- SEE ALSO
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Time: 20:06:01 GMT, August 25, 2015