1PROBE::IOBLOCK.REQ(3stap)IO Scheduler and block IO TapsPROBE::IOBLOCK.REQ(3stap)
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NAME

6       probe::ioblock.request - Fires whenever making a generic block I/O
7       request.
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SYNOPSIS

10       ioblock.request
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VALUES

13       None
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DESCRIPTION

16       name - name of the probe point devname - block device name ino - i-node
17       number of the mapped file sector - beginning sector for the entire bio
18       flags - see below BIO_UPTODATE 0 ok after I/O completion BIO_RW_BLOCK 1
19       RW_AHEAD set, and read/write would block BIO_EOF 2 out-out-bounds error
20       BIO_SEG_VALID 3 nr_hw_seg valid BIO_CLONED 4 doesn't own data
21       BIO_BOUNCED 5 bio is a bounce bio BIO_USER_MAPPED 6 contains user pages
22       BIO_EOPNOTSUPP 7 not supported
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24       rw - binary trace for read/write request vcnt - bio vector count which
25       represents number of array element (page, offset, length) which make up
26       this I/O request idx - offset into the bio vector array phys_segments -
27       number of segments in this bio after physical address coalescing is
28       performed hw_segments - number of segments after physical and DMA
29       remapping hardware coalescing is performed size - total size in bytes
30       bdev - target block device bdev_contains - points to the device object
31       which contains the partition (when bio structure represents a
32       partition) p_start_sect - points to the start sector of the partition
33       structure of the device
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CONTEXT

36       The process makes block I/O request
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40SystemTap Tapset Reference        August 2011        PROBE::IOBLOCK.REQ(3stap)
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