1This document gives a brief rationale for the TREE_RCU-related test
2cases, a group that includes PREEMPT_RCU.
3
4
5Kconfig Parameters:
6
7CONFIG_DEBUG_LOCK_ALLOC -- Do three, covering CONFIG_PROVE_LOCKING & not.
8CONFIG_DEBUG_OBJECTS_RCU_HEAD -- Do one.
9CONFIG_HOTPLUG_CPU -- Do half.  (Every second.)
10CONFIG_HZ_PERIODIC -- Do one.
11CONFIG_NO_HZ_IDLE -- Do those not otherwise specified. (Groups of two.)
12CONFIG_NO_HZ_FULL -- Do two, one with partial CPU enablement.
13CONFIG_PREEMPT -- Do half.  (First three and #8.)
14CONFIG_PROVE_LOCKING -- Do several, covering CONFIG_DEBUG_LOCK_ALLOC=y and not.
15CONFIG_PROVE_RCU -- Hardwired to CONFIG_PROVE_LOCKING.
16CONFIG_RCU_BOOST -- one of PREEMPT_RCU.
17CONFIG_RCU_FANOUT -- Cover hierarchy, but overlap with others.
18CONFIG_RCU_FANOUT_LEAF -- Do one non-default.
19CONFIG_RCU_FAST_NO_HZ -- Do one, but not with all nohz_full CPUs.
20CONFIG_RCU_NOCB_CPU -- Do three, one with no rcu_nocbs CPUs, one with
21	rcu_nocbs=0, and one with all rcu_nocbs CPUs.
22CONFIG_RCU_TRACE -- Do half.
23CONFIG_SMP -- Need one !SMP for PREEMPT_RCU.
24CONFIG_RCU_EXPERT=n -- Do a few, but these have to be vanilla configurations.
25CONFIG_RCU_EQS_DEBUG -- Do at least one for CONFIG_NO_HZ_FULL and not.
26
27RCU-bh: Do one with PREEMPT and one with !PREEMPT.
28RCU-sched: Do one with PREEMPT but not BOOST.
29
30
31Boot parameters:
32
33nohz_full - do at least one.
34maxcpu -- do at least one.
35rcupdate.rcu_self_test_bh -- Do at least one each, offloaded and not.
36rcupdate.rcu_self_test_sched -- Do at least one each, offloaded and not.
37rcupdate.rcu_self_test -- Do at least one each, offloaded and not.
38rcutree.rcu_fanout_exact -- Do at least one.
39
40
41Kconfig Parameters Ignored:
42
43CONFIG_64BIT
44
45	Used only to check CONFIG_RCU_FANOUT value, inspection suffices.
46
47CONFIG_PREEMPT_COUNT
48CONFIG_PREEMPT_RCU
49
50	Redundant with CONFIG_PREEMPT, ignore.
51
52CONFIG_RCU_BOOST_DELAY
53
54	Inspection suffices, ignore.
55
56CONFIG_RCU_CPU_STALL_TIMEOUT
57
58	Inspection suffices, ignore.
59
60CONFIG_RCU_STALL_COMMON
61
62	Implied by TREE_RCU and PREEMPT_RCU.
63
64CONFIG_RCU_TORTURE_TEST
65CONFIG_RCU_TORTURE_TEST_RUNNABLE
66
67	Always used in KVM testing.
68
69CONFIG_PREEMPT_RCU
70CONFIG_TREE_RCU
71CONFIG_TINY_RCU
72CONFIG_TASKS_RCU
73
74	These are controlled by CONFIG_PREEMPT and/or CONFIG_SMP.
75
76CONFIG_SRCU
77
78	Selected by CONFIG_RCU_TORTURE_TEST, so cannot disable.
79
80
81boot parameters ignored: TBD
82