suse man page for trace_softirq_entry

TRACE_SOFTIRQ_ENTRY(9)							IRQ						    TRACE_SOFTIRQ_ENTRY(9)

NAME
       trace_softirq_entry - called immediately before the softirq handler

SYNOPSIS
       void trace_softirq_entry(struct softirq_action * h, struct softirq_action * vec);

ARGUMENTS
       h
	   pointer to struct softirq_action

       vec
	   pointer to first struct softirq_action in softirq_vec array

DESCRIPTION
       The h parameter, contains a pointer to the struct softirq_action which has a pointer to the action handler that is called. By subtracting
       the vec pointer from the h pointer, we can determine the softirq number. Also, when used in combination with the softirq_exit tracepoint we
       can determine the softirq latency.

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

       William Cohen <wcohen@redhat.com>
	   Author.

COPYRIGHT
Kernel Hackers Manual 2.6.					     July 2010						    TRACE_SOFTIRQ_ENTRY(9)