1This document gives a brief rationale for the TREE_RCU-related test
2cases, a group that includes TREE_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 all but two, covering CONFIG_PROVE_RCU and not.
16CONFIG_PROVE_RCU -- Do all but one under CONFIG_PROVE_LOCKING.
17CONFIG_RCU_BOOST -- one of TREE_PREEMPT_RCU.
18CONFIG_RCU_BOOST_PRIO -- set to 2 for _BOOST testing.
19CONFIG_RCU_CPU_STALL_INFO -- do one with and without _VERBOSE.
20CONFIG_RCU_CPU_STALL_VERBOSE -- do one with and without _INFO.
21CONFIG_RCU_FANOUT -- Cover hierarchy as currently, but overlap with others.
22CONFIG_RCU_FANOUT_EXACT -- Do one.
23CONFIG_RCU_FANOUT_LEAF -- Do one non-default.
24CONFIG_RCU_FAST_NO_HZ -- Do one, but not with CONFIG_RCU_NOCB_CPU_ALL.
25CONFIG_RCU_NOCB_CPU -- Do three, see below.
26CONFIG_RCU_NOCB_CPU_ALL -- Do one.
27CONFIG_RCU_NOCB_CPU_NONE -- Do one.
28CONFIG_RCU_NOCB_CPU_ZERO -- Do one.
29CONFIG_RCU_TRACE -- Do half.
30CONFIG_SMP -- Need one !SMP for TREE_PREEMPT_RCU.
31RCU-bh: Do one with PREEMPT and one with !PREEMPT.
32RCU-sched: Do one with PREEMPT but not BOOST.
33
34
35Hierarchy:
36
37TREE01.	CONFIG_NR_CPUS=8, CONFIG_RCU_FANOUT=8, CONFIG_RCU_FANOUT_EXACT=n.
38TREE02.	CONFIG_NR_CPUS=8, CONFIG_RCU_FANOUT=3, CONFIG_RCU_FANOUT_EXACT=n,
39	CONFIG_RCU_FANOUT_LEAF=3.
40TREE03.	CONFIG_NR_CPUS=8, CONFIG_RCU_FANOUT=4, CONFIG_RCU_FANOUT_EXACT=n,
41	CONFIG_RCU_FANOUT_LEAF=4.
42TREE04.	CONFIG_NR_CPUS=8, CONFIG_RCU_FANOUT=2, CONFIG_RCU_FANOUT_EXACT=n,
43	CONFIG_RCU_FANOUT_LEAF=2.
44TREE05.	CONFIG_NR_CPUS=8, CONFIG_RCU_FANOUT=6, CONFIG_RCU_FANOUT_EXACT=n
45	CONFIG_RCU_FANOUT_LEAF=6.
46TREE06.	CONFIG_NR_CPUS=8, CONFIG_RCU_FANOUT=6, CONFIG_RCU_FANOUT_EXACT=y
47	CONFIG_RCU_FANOUT_LEAF=6.
48TREE07.	CONFIG_NR_CPUS=16, CONFIG_RCU_FANOUT=2, CONFIG_RCU_FANOUT_EXACT=n,
49	CONFIG_RCU_FANOUT_LEAF=2.
50TREE08.	CONFIG_NR_CPUS=16, CONFIG_RCU_FANOUT=3, CONFIG_RCU_FANOUT_EXACT=y,
51	CONFIG_RCU_FANOUT_LEAF=2.
52TREE09.	CONFIG_NR_CPUS=1.
53
54
55Kconfig Parameters Ignored:
56
57CONFIG_64BIT
58
59	Used only to check CONFIG_RCU_FANOUT value, inspection suffices.
60
61CONFIG_NO_HZ_FULL_SYSIDLE_SMALL
62
63	Defer until Frederic uses this.
64
65CONFIG_PREEMPT_COUNT
66CONFIG_PREEMPT_RCU
67
68	Redundant with CONFIG_PREEMPT, ignore.
69
70CONFIG_RCU_BOOST_DELAY
71
72	Inspection suffices, ignore.
73
74CONFIG_RCU_CPU_STALL_TIMEOUT
75
76	Inspection suffices, ignore.
77
78CONFIG_RCU_STALL_COMMON
79
80	Implied by TREE_RCU and TREE_PREEMPT_RCU.
81
82CONFIG_RCU_TORTURE_TEST
83CONFIG_RCU_TORTURE_TEST_RUNNABLE
84
85	Always used in KVM testing.
86
87CONFIG_RCU_USER_QS
88
89	Redundant with CONFIG_NO_HZ_FULL.
90
91CONFIG_TREE_PREEMPT_RCU
92CONFIG_TREE_RCU
93
94	These are controlled by CONFIG_PREEMPT.
95