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