centos man page for trace_block_sleeprq

TRACE_BLOCK_SLEEPRQ(9)						     Block IO						    TRACE_BLOCK_SLEEPRQ(9)

NAME
       trace_block_sleeprq - waiting to get a free request entry in queue for block IO operation

SYNOPSIS
       void trace_block_sleeprq(struct request_queue * q, struct bio * bio, int rw);

ARGUMENTS
       q
	   queue for operation

       bio
	   pending block IO operation

       rw
	   low bit indicates a read (0) or a write (1)

DESCRIPTION
       In the case where a request struct cannot be provided for queue q the process needs to wait for an request struct to become available. This
       tracepoint event is generated each time the process goes to sleep waiting for request struct become available.

AUTHORS
       Jason Baron <jbaron@redhat.com>
	   Author.

       William Cohen <wcohen@redhat.com>
	   Author.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014						    TRACE_BLOCK_SLEEPRQ(9)