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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-05-10 12:50:55 -0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-05-10 13:30:46 -0400 |
| commit | de4d195308ad589626571dbe5789cebf9695a204 (patch) | |
| tree | 77a6bd6946594ea4e7513aaa73009295530960a1 /init | |
| parent | dc9edaab90de9441cc28ac570b23b0d2bdba7879 (diff) | |
| parent | 20652ed6e44f4963281b65209b917be86ac6765b (diff) | |
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar:
"The main changes are:
- Debloat RCU headers
- Parallelize SRCU callback handling (plus overlapping patches)
- Improve the performance of Tree SRCU on a CPU-hotplug stress test
- Documentation updates
- Miscellaneous fixes"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (74 commits)
rcu: Open-code the rcu_cblist_n_lazy_cbs() function
rcu: Open-code the rcu_cblist_n_cbs() function
rcu: Open-code the rcu_cblist_empty() function
rcu: Separately compile large rcu_segcblist functions
srcu: Debloat the <linux/rcu_segcblist.h> header
srcu: Adjust default auto-expediting holdoff
srcu: Specify auto-expedite holdoff time
srcu: Expedite first synchronize_srcu() when idle
srcu: Expedited grace periods with reduced memory contention
srcu: Make rcutorture writer stalls print SRCU GP state
srcu: Exact tracking of srcu_data structures containing callbacks
srcu: Make SRCU be built by default
srcu: Fix Kconfig botch when SRCU not selected
rcu: Make non-preemptive schedule be Tasks RCU quiescent state
srcu: Expedite srcu_schedule_cbs_snp() callback invocation
srcu: Parallelize callback handling
kvm: Move srcu_struct fields to end of struct kvm
rcu: Fix typo in PER_RCU_NODE_PERIOD header comment
rcu: Use true/false in assignment to bool
rcu: Use bool value directly
...
Diffstat (limited to 'init')
| -rw-r--r-- | init/Kconfig | 43 |
1 files changed, 41 insertions, 2 deletions
diff --git a/init/Kconfig b/init/Kconfig index a92f27da4a27..1d3475fc9496 100644 --- a/init/Kconfig +++ b/init/Kconfig | |||
| @@ -521,11 +521,41 @@ config RCU_EXPERT | |||
| 521 | 521 | ||
| 522 | config SRCU | 522 | config SRCU |
| 523 | bool | 523 | bool |
| 524 | default y | ||
| 524 | help | 525 | help |
| 525 | This option selects the sleepable version of RCU. This version | 526 | This option selects the sleepable version of RCU. This version |
| 526 | permits arbitrary sleeping or blocking within RCU read-side critical | 527 | permits arbitrary sleeping or blocking within RCU read-side critical |
| 527 | sections. | 528 | sections. |
| 528 | 529 | ||
| 530 | config CLASSIC_SRCU | ||
| 531 | bool "Use v4.11 classic SRCU implementation" | ||
| 532 | default n | ||
| 533 | depends on RCU_EXPERT && SRCU | ||
| 534 | help | ||
| 535 | This option selects the traditional well-tested classic SRCU | ||
| 536 | implementation from v4.11, as might be desired for enterprise | ||
| 537 | Linux distributions. Without this option, the shiny new | ||
| 538 | Tiny SRCU and Tree SRCU implementations are used instead. | ||
| 539 | At some point, it is hoped that Tiny SRCU and Tree SRCU | ||
| 540 | will accumulate enough test time and confidence to allow | ||
| 541 | Classic SRCU to be dropped entirely. | ||
| 542 | |||
| 543 | Say Y if you need a rock-solid SRCU. | ||
| 544 | |||
| 545 | Say N if you would like help test Tree SRCU. | ||
| 546 | |||
| 547 | config TINY_SRCU | ||
| 548 | bool | ||
| 549 | default y if SRCU && TINY_RCU && !CLASSIC_SRCU | ||
| 550 | help | ||
| 551 | This option selects the single-CPU non-preemptible version of SRCU. | ||
| 552 | |||
| 553 | config TREE_SRCU | ||
| 554 | bool | ||
| 555 | default y if SRCU && !TINY_RCU && !CLASSIC_SRCU | ||
| 556 | help | ||
| 557 | This option selects the full-fledged version of SRCU. | ||
| 558 | |||
| 529 | config TASKS_RCU | 559 | config TASKS_RCU |
| 530 | bool | 560 | bool |
| 531 | default n | 561 | default n |
| @@ -543,6 +573,9 @@ config RCU_STALL_COMMON | |||
| 543 | the tiny variants to disable RCU CPU stall warnings, while | 573 | the tiny variants to disable RCU CPU stall warnings, while |
| 544 | making these warnings mandatory for the tree variants. | 574 | making these warnings mandatory for the tree variants. |
| 545 | 575 | ||
| 576 | config RCU_NEED_SEGCBLIST | ||
| 577 | def_bool ( TREE_RCU || PREEMPT_RCU || TINY_SRCU || TREE_SRCU ) | ||
| 578 | |||
| 546 | config CONTEXT_TRACKING | 579 | config CONTEXT_TRACKING |
| 547 | bool | 580 | bool |
| 548 | 581 | ||
| @@ -612,11 +645,17 @@ config RCU_FANOUT_LEAF | |||
| 612 | initialization. These systems tend to run CPU-bound, and thus | 645 | initialization. These systems tend to run CPU-bound, and thus |
| 613 | are not helped by synchronized interrupts, and thus tend to | 646 | are not helped by synchronized interrupts, and thus tend to |
| 614 | skew them, which reduces lock contention enough that large | 647 | skew them, which reduces lock contention enough that large |
| 615 | leaf-level fanouts work well. | 648 | leaf-level fanouts work well. That said, setting leaf-level |
| 649 | fanout to a large number will likely cause problematic | ||
| 650 | lock contention on the leaf-level rcu_node structures unless | ||
| 651 | you boot with the skew_tick kernel parameter. | ||
| 616 | 652 | ||
| 617 | Select a specific number if testing RCU itself. | 653 | Select a specific number if testing RCU itself. |
| 618 | 654 | ||
| 619 | Select the maximum permissible value for large systems. | 655 | Select the maximum permissible value for large systems, but |
| 656 | please understand that you may also need to set the skew_tick | ||
| 657 | kernel boot parameter to avoid contention on the rcu_node | ||
| 658 | structure's locks. | ||
| 620 | 659 | ||
| 621 | Take the default if unsure. | 660 | Take the default if unsure. |
| 622 | 661 | ||