1PROBE::IOBLOCK_TRACE(3staIpO)Scheduler and block IO TaPpRsOBE::IOBLOCK_TRACE(3stap)
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NAME

6       probe::ioblock_trace.request - Fires just as a generic block I/O
7       request is created for a bio.
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SYNOPSIS

10       ioblock_trace.request
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VALUES

13       None
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DESCRIPTION

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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CONTEXT

35       The process makes block I/O request
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39SystemTap Tapset Reference        August 2011      PROBE::IOBLOCK_TRACE(3stap)
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