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