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      1 This document gives a brief rationale for the TREE_RCU-related test
      2 cases, a group that includes PREEMPT_RCU.
      3 
      4 
      5 Kconfig Parameters:
      6 
      7 CONFIG_DEBUG_LOCK_ALLOC -- Do three, covering CONFIG_PROVE_LOCKING & not.
      8 CONFIG_DEBUG_OBJECTS_RCU_HEAD -- Do one.
      9 CONFIG_HOTPLUG_CPU -- Do half.  (Every second.)
     10 CONFIG_HZ_PERIODIC -- Do one.
     11 CONFIG_NO_HZ_IDLE -- Do those not otherwise specified. (Groups of two.)
     12 CONFIG_NO_HZ_FULL -- Do two, one with CONFIG_NO_HZ_FULL_SYSIDLE.
     13 CONFIG_NO_HZ_FULL_SYSIDLE -- Do one.
     14 CONFIG_PREEMPT -- Do half.  (First three and #8.)
     15 CONFIG_PROVE_LOCKING -- Do several, covering CONFIG_DEBUG_LOCK_ALLOC=y and not.
     16 CONFIG_PROVE_RCU -- Hardwired to CONFIG_PROVE_LOCKING.
     17 CONFIG_PROVE_RCU_REPEATEDLY -- Do one.
     18 CONFIG_RCU_BOOST -- one of PREEMPT_RCU.
     19 CONFIG_RCU_KTHREAD_PRIO -- set to 2 for _BOOST testing.
     20 CONFIG_RCU_FANOUT -- Cover hierarchy, but overlap with others.
     21 CONFIG_RCU_FANOUT_LEAF -- Do one non-default.
     22 CONFIG_RCU_FAST_NO_HZ -- Do one, but not with CONFIG_RCU_NOCB_CPU_ALL.
     23 CONFIG_RCU_NOCB_CPU -- Do three, see below.
     24 CONFIG_RCU_NOCB_CPU_ALL -- Do one.
     25 CONFIG_RCU_NOCB_CPU_NONE -- Do one.
     26 CONFIG_RCU_NOCB_CPU_ZERO -- Do one.
     27 CONFIG_RCU_TRACE -- Do half.
     28 CONFIG_SMP -- Need one !SMP for PREEMPT_RCU.
     29 CONFIG_RCU_EXPERT=n -- Do a few, but these have to be vanilla configurations.
     30 CONFIG_RCU_EQS_DEBUG -- Do at least one for CONFIG_NO_HZ_FULL and not.
     31 CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP -- Do for all but a couple TREE scenarios.
     32 CONFIG_RCU_TORTURE_TEST_SLOW_INIT -- Do for all but a couple TREE scenarios.
     33 CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT -- Do for all but a couple TREE scenarios.
     34 
     35 RCU-bh: Do one with PREEMPT and one with !PREEMPT.
     36 RCU-sched: Do one with PREEMPT but not BOOST.
     37 
     38 
     39 Boot parameters:
     40 
     41 nohz_full - do at least one.
     42 maxcpu -- do at least one.
     43 rcupdate.rcu_self_test_bh -- Do at least one each, offloaded and not.
     44 rcupdate.rcu_self_test_sched -- Do at least one each, offloaded and not.
     45 rcupdate.rcu_self_test -- Do at least one each, offloaded and not.
     46 rcutree.rcu_fanout_exact -- Do at least one.
     47 
     48 
     49 Kconfig Parameters Ignored:
     50 
     51 CONFIG_64BIT
     52 
     53 	Used only to check CONFIG_RCU_FANOUT value, inspection suffices.
     54 
     55 CONFIG_NO_HZ_FULL_SYSIDLE_SMALL
     56 
     57 	Defer until Frederic uses this.
     58 
     59 CONFIG_PREEMPT_COUNT
     60 CONFIG_PREEMPT_RCU
     61 
     62 	Redundant with CONFIG_PREEMPT, ignore.
     63 
     64 CONFIG_RCU_BOOST_DELAY
     65 
     66 	Inspection suffices, ignore.
     67 
     68 CONFIG_RCU_CPU_STALL_TIMEOUT
     69 
     70 	Inspection suffices, ignore.
     71 
     72 CONFIG_RCU_STALL_COMMON
     73 
     74 	Implied by TREE_RCU and PREEMPT_RCU.
     75 
     76 CONFIG_RCU_TORTURE_TEST
     77 CONFIG_RCU_TORTURE_TEST_RUNNABLE
     78 
     79 	Always used in KVM testing.
     80 
     81 CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT_DELAY
     82 CONFIG_RCU_TORTURE_TEST_SLOW_INIT_DELAY
     83 CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP_DELAY
     84 
     85 	Inspection suffices, ignore.
     86 
     87 CONFIG_PREEMPT_RCU
     88 CONFIG_TREE_RCU
     89 CONFIG_TINY_RCU
     90 
     91 	These are controlled by CONFIG_PREEMPT and/or CONFIG_SMP.
     92 
     93 CONFIG_SPARSE_RCU_POINTER
     94 
     95 	Makes sense only for sparse runs, not for kernel builds.
     96 
     97 CONFIG_SRCU
     98 CONFIG_TASKS_RCU
     99 
    100 	Selected by CONFIG_RCU_TORTURE_TEST, so cannot disable.
    101 
    102 CONFIG_RCU_TRACE
    103 
    104 	Implied by CONFIG_RCU_TRACE for Tree RCU.
    105 
    106 
    107 boot parameters ignored: TBD
    108