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Commit 98953135 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

checkpatch: Remove checks for expedited grace periods 



There was a time when the expedited grace-period primitives
(synchronize_rcu_expedited(), synchronize_rcu_bh_expedited(), and
synchronize_sched_expedited()) used rather antisocial kernel
facilities like try_stop_cpus().  However, they have since been
housebroken to use only single-CPU IPIs, and typically cause less
disturbance than a scheduling-clock interrupt.  Furthermore, this
disturbance can be eliminated entirely using NO_HZ_FULL on the
one hand or the rcupdate.rcu_normal boot parameter on the other.

This commit therefore removes checkpatch's complaints about use
of the expedited RCU primitives.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent dcfc315b

scripts/checkpatch.pl

+0 −17
Original line number Diff line number Diff line
@@ -5533,23 +5533,6 @@ sub process { 
			}

		}



# Check for expedited grace periods that interrupt non-idle non-nohz

# online CPUs.  These expedited can therefore degrade real-time response

# if used carelessly, and should be avoided where not absolutely

# needed.  It is always OK to use synchronize_rcu_expedited() and

# synchronize_sched_expedited() at boot time (before real-time applications

# start) and in error situations where real-time response is compromised in

# any case.  Note that synchronize_srcu_expedited() does -not- interrupt

# other CPUs, so don't warn on uses of synchronize_srcu_expedited().

# Of course, nothing comes for free, and srcu_read_lock() and

# srcu_read_unlock() do contain full memory barriers in payment for

# synchronize_srcu_expedited() non-interruption properties.

		if ($line =~ /\b(synchronize_rcu_expedited|synchronize_sched_expedited)\(/) {

			WARN("EXPEDITED_RCU_GRACE_PERIOD",

			     "expedited RCU grace periods should be avoided where they can degrade real-time response\n" . $herecurr);



		}



# check of hardware specific defines

		if ($line =~ m@^.\s*\#\s*if.*\b(__i386__|__powerpc64__|__sun__|__s390x__)\b@ && $realfile !~ m@include/asm-@) {

			CHK("ARCH_DEFINES",