trace_block_split(9) [centos man page]

TRACE_BLOCK_SPLIT(9)						     Block IO						      TRACE_BLOCK_SPLIT(9)

NAME

       trace_block_split - split a single bio struct into two bio structs

SYNOPSIS

       void trace_block_split(struct request_queue * q, struct bio * bio, unsigned int new_sector);

ARGUMENTS

       q
	   queue containing the bio

       bio
	   block operation being split

       new_sector
	   The starting sector for the new bio

DESCRIPTION

       The bio request bio in request queue q needs to be split into two bio requests. The newly created bio request starts at new_sector. This
       split may be required due to hardware limitation such as operation crossing device boundaries in a RAID system.

AUTHORS

       Jason Baron <jbaron@redhat.com>
	   Author.

       William Cohen <wcohen@redhat.com>
	   Author.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						      TRACE_BLOCK_SPLIT(9)

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

NAME

       probe::ioblock_trace.end - Fires whenever a block I/O transfer is complete.

SYNOPSIS

       ioblock_trace.end

VALUES

       None

DESCRIPTION

       name - name of the probe point q - request queue on which this bio was queued.  devname - block device name 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 signals the transfer is done.

SystemTap Tapset Reference					     June 2014					       PROBE::IOBLOCK_TRACE(3stap)