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
       None

DESCRIPTION
       name - name of the probe point q - request queue on which this bio was queued.  devname - device for which a buffer
       bounce was needed.  ino - i-node number of the mapped file bytes_done - number of bytes transferred 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
       makes 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.  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

CONTEXT
       The process creating a block IO request.



SystemTap Tapset Reference                                 August 2011                               PROBE::IOBLOCK_TRACE(3stap)