1PROBE::IOBLOCK_TRACE(3staIpO)Scheduler and block IO TaPpRsOBE::IOBLOCK_TRACE(3stap)
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6 probe::ioblock_trace.request - Fires just as a generic block I/O
7 request is created for a bio.
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10 ioblock_trace.request
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13 None
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16 name - name of the probe point q - request queue on which this bio was
17 queued. devname - block device name ino - i-node number of the mapped
18 file bytes_done - number of bytes transferred sector - beginning sector
19 for the entire bio flags - see below BIO_UPTODATE 0 ok after I/O
20 completion BIO_RW_BLOCK 1 RW_AHEAD set, and read/write would block
21 BIO_EOF 2 out-out-bounds error BIO_SEG_VALID 3 nr_hw_seg valid
22 BIO_CLONED 4 doesn't own data BIO_BOUNCED 5 bio is a bounce bio
23 BIO_USER_MAPPED 6 contains user pages BIO_EOPNOTSUPP 7 not supported
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25 rw - binary trace for read/write request vcnt - bio vector count which
26 represents number of array element (page, offset, length) which make up
27 this I/O request idx - offset into the bio vector array phys_segments -
28 number of segments in this bio after physical address coalescing is
29 performed. size - total size in bytes bdev - target block device
30 bdev_contains - points to the device object which contains the
31 partition (when bio structure represents a partition) p_start_sect -
32 points to the start sector of the partition structure of the device
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35 The process makes block I/O request
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39SystemTap Tapset Reference August 2011 PROBE::IOBLOCK_TRACE(3stap)