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authorLinus Torvalds <torvalds@linux-foundation.org>2008-12-30 19:10:19 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2008-12-30 19:10:19 -0500
commit5f34fe1cfc1bdd8b4711bbe37421fba4ed0d1ed4 (patch)
tree85b21c8bb0e53005bd970d648ca093acfd0584a3 /init/Kconfig
parenteca1bf5b4fab56d2feb1572d34d59fcd92ea7df3 (diff)
parent6638101c1124c19c8a65b1645e4ecd09e0572f3e (diff)
Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (63 commits) stacktrace: provide save_stack_trace_tsk() weak alias rcu: provide RCU options on non-preempt architectures too printk: fix discarding message when recursion_bug futex: clean up futex_(un)lock_pi fault handling "Tree RCU": scalable classic RCU implementation futex: rename field in futex_q to clarify single waiter semantics x86/swiotlb: add default swiotlb_arch_range_needs_mapping x86/swiotlb: add default phys<->bus conversion x86: unify pci iommu setup and allow swiotlb to compile for 32 bit x86: add swiotlb allocation functions swiotlb: consolidate swiotlb info message printing swiotlb: support bouncing of HighMem pages swiotlb: factor out copy to/from device swiotlb: add arch hook to force mapping swiotlb: allow architectures to override phys<->bus<->phys conversions swiotlb: add comment where we handle the overflow of a dma mask on 32 bit rcu: fix rcutorture behavior during reboot resources: skip sanity check of busy resources swiotlb: move some definitions to header swiotlb: allow architectures to override swiotlb pool allocation ... Fix up trivial conflicts in arch/x86/kernel/Makefile arch/x86/mm/init_32.c include/linux/hardirq.h as per Ingo's suggestions.
Diffstat (limited to 'init/Kconfig')
-rw-r--r--init/Kconfig86
1 files changed, 83 insertions, 3 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 8a63c404ef4..13627191a60 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -936,10 +936,90 @@ source "block/Kconfig"
936config PREEMPT_NOTIFIERS 936config PREEMPT_NOTIFIERS
937 bool 937 bool
938 938
939choice
940 prompt "RCU Implementation"
941 default CLASSIC_RCU
942
939config CLASSIC_RCU 943config CLASSIC_RCU
940 def_bool !PREEMPT_RCU 944 bool "Classic RCU"
941 help 945 help
942 This option selects the classic RCU implementation that is 946 This option selects the classic RCU implementation that is
943 designed for best read-side performance on non-realtime 947 designed for best read-side performance on non-realtime
944 systems. Classic RCU is the default. Note that the 948 systems.
945 PREEMPT_RCU symbol is used to select/deselect this option. 949
950 Select this option if you are unsure.
951
952config TREE_RCU
953 bool "Tree-based hierarchical RCU"
954 help
955 This option selects the RCU implementation that is
956 designed for very large SMP system with hundreds or
957 thousands of CPUs.
958
959config PREEMPT_RCU
960 bool "Preemptible RCU"
961 depends on PREEMPT
962 help
963 This option reduces the latency of the kernel by making certain
964 RCU sections preemptible. Normally RCU code is non-preemptible, if
965 this option is selected then read-only RCU sections become
966 preemptible. This helps latency, but may expose bugs due to
967 now-naive assumptions about each RCU read-side critical section
968 remaining on a given CPU through its execution.
969
970endchoice
971
972config RCU_TRACE
973 bool "Enable tracing for RCU"
974 depends on TREE_RCU || PREEMPT_RCU
975 help
976 This option provides tracing in RCU which presents stats
977 in debugfs for debugging RCU implementation.
978
979 Say Y here if you want to enable RCU tracing
980 Say N if you are unsure.
981
982config RCU_FANOUT
983 int "Tree-based hierarchical RCU fanout value"
984 range 2 64 if 64BIT
985 range 2 32 if !64BIT
986 depends on TREE_RCU
987 default 64 if 64BIT
988 default 32 if !64BIT
989 help
990 This option controls the fanout of hierarchical implementations
991 of RCU, allowing RCU to work efficiently on machines with
992 large numbers of CPUs. This value must be at least the cube
993 root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit
994 systems and up to 262,144 for 64-bit systems.
995
996 Select a specific number if testing RCU itself.
997 Take the default if unsure.
998
999config RCU_FANOUT_EXACT
1000 bool "Disable tree-based hierarchical RCU auto-balancing"
1001 depends on TREE_RCU
1002 default n
1003 help
1004 This option forces use of the exact RCU_FANOUT value specified,
1005 regardless of imbalances in the hierarchy. This is useful for
1006 testing RCU itself, and might one day be useful on systems with
1007 strong NUMA behavior.
1008
1009 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
1010
1011 Say N if unsure.
1012
1013config TREE_RCU_TRACE
1014 def_bool RCU_TRACE && TREE_RCU
1015 select DEBUG_FS
1016 help
1017 This option provides tracing for the TREE_RCU implementation,
1018 permitting Makefile to trivially select kernel/rcutree_trace.c.
1019
1020config PREEMPT_RCU_TRACE
1021 def_bool RCU_TRACE && PREEMPT_RCU
1022 select DEBUG_FS
1023 help
1024 This option provides tracing for the PREEMPT_RCU implementation,
1025 permitting Makefile to trivially select kernel/rcupreempt_trace.c.