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PROBE::IOBLOCK_TRACE(3stap) IO Scheduler and block IO Taps PROBE::IOBLOCK_TRACE(3stap)

NAME

probe::ioblock_trace.bounce - Fires whenever a buffer bounce is needed for at least one page of a block IO request.

SYNOPSIS

ioblock_trace.bounce

VALUES

bdev_contains
points to the device object which contains the partition (when bio structure represents a partition)

size

total size in bytes

ino

i-node number of the mapped file

rw

binary trace for read/write request

sector

beginning sector for the entire bio

idx

offset into the bio vector array phys_segments - number of segments in this bio after physical address coalescing is performed.

name

name of the probe point

bdev

target block device

vcnt

bio vector count which represents number of array element (page, offset, length) which makes up this I/O request

q

request queue on which this bio was queued.

bytes_done

number of bytes transferred

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

p_start_sect

points to the start sector of the partition structure of the device

devname

device for which a buffer bounce was needed.

opf

operations and flags

CONTEXT

The process creating a block IO request.

SEE ALSO0

tapset::ioblock(3stap)
November 2020 SystemTap Tapset Reference