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 CONFIG_NO_HZ_FULL_SYSIDLE.
13CONFIG_NO_HZ_FULL_SYSIDLE -- Do one.
14CONFIG_PREEMPT -- Do half.  (First three and #8.)
15CONFIG_PROVE_LOCKING -- Do several, covering CONFIG_DEBUG_LOCK_ALLOC=y and not.
16CONFIG_PROVE_RCU -- Hardwired to CONFIG_PROVE_LOCKING.
17CONFIG_RCU_BOOST -- one of PREEMPT_RCU.
18CONFIG_RCU_KTHREAD_PRIO -- set to 2 for _BOOST testing.
19CONFIG_RCU_CPU_STALL_INFO -- Now default, avoid at least twice.
20CONFIG_RCU_FANOUT -- Cover hierarchy, but overlap with others.
21CONFIG_RCU_FANOUT_LEAF -- Do one non-default.
22CONFIG_RCU_FAST_NO_HZ -- Do one, but not with CONFIG_RCU_NOCB_CPU_ALL.
23CONFIG_RCU_NOCB_CPU -- Do three, see below.
24CONFIG_RCU_NOCB_CPU_ALL -- Do one.
25CONFIG_RCU_NOCB_CPU_NONE -- Do one.
26CONFIG_RCU_NOCB_CPU_ZERO -- Do one.
27CONFIG_RCU_TRACE -- Do half.
28CONFIG_SMP -- Need one !SMP for PREEMPT_RCU.
29!RCU_EXPERT -- Do a few, but these have to be vanilla configurations.
30RCU-bh: Do one with PREEMPT and one with !PREEMPT.
31RCU-sched: Do one with PREEMPT but not BOOST.
32
33
34Boot parameters:
35
36nohz_full - do at least one.
37maxcpu -- do at least one.
38rcupdate.rcu_self_test_bh -- Do at least one each, offloaded and not.
39rcupdate.rcu_self_test_sched -- Do at least one each, offloaded and not.
40rcupdate.rcu_self_test -- Do at least one each, offloaded and not.
41rcutree.rcu_fanout_exact -- Do at least one.
42
43
44Kconfig Parameters Ignored:
45
46CONFIG_64BIT
47
48	Used only to check CONFIG_RCU_FANOUT value, inspection suffices.
49
50CONFIG_NO_HZ_FULL_SYSIDLE_SMALL
51
52	Defer until Frederic uses this.
53
54CONFIG_PREEMPT_COUNT
55CONFIG_PREEMPT_RCU
56
57	Redundant with CONFIG_PREEMPT, ignore.
58
59CONFIG_RCU_BOOST_DELAY
60
61	Inspection suffices, ignore.
62
63CONFIG_RCU_CPU_STALL_TIMEOUT
64
65	Inspection suffices, ignore.
66
67CONFIG_RCU_STALL_COMMON
68
69	Implied by TREE_RCU and PREEMPT_RCU.
70
71CONFIG_RCU_TORTURE_TEST
72CONFIG_RCU_TORTURE_TEST_RUNNABLE
73
74	Always used in KVM testing.
75
76CONFIG_RCU_USER_QS
77
78	Redundant with CONFIG_NO_HZ_FULL.
79
80CONFIG_PREEMPT_RCU
81CONFIG_TREE_RCU
82
83	These are controlled by CONFIG_PREEMPT.
84