PROBE::IOBLOCK.REQ(3stap) IO Scheduler and block IO Taps PROBE::IOBLOCK.REQ(3stap)NAME
probe::ioblock.request - Fires whenever making a generic block I/O request.
name - name of the probe point devname - block device name ino - i-node number of the mapped file 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 hw_segments - number of segments after physical and DMA remapping hardware 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.REQ(3stap)
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