diff options
Diffstat (limited to 'init')
| -rw-r--r-- | init/Kconfig | 39 |
1 files changed, 37 insertions, 2 deletions
diff --git a/init/Kconfig b/init/Kconfig index a92f27da4a27..4119a44e4157 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -526,6 +526,35 @@ config SRCU permits arbitrary sleeping or blocking within RCU read-side critical sections. +config CLASSIC_SRCU + bool "Use v4.11 classic SRCU implementation" + default n + depends on RCU_EXPERT && SRCU + help + This option selects the traditional well-tested classic SRCU + implementation from v4.11, as might be desired for enterprise + Linux distributions. Without this option, the shiny new + Tiny SRCU and Tree SRCU implementations are used instead. + At some point, it is hoped that Tiny SRCU and Tree SRCU + will accumulate enough test time and confidence to allow + Classic SRCU to be dropped entirely. + + Say Y if you need a rock-solid SRCU. + + Say N if you would like help test Tree SRCU. + +config TINY_SRCU + bool + default y if TINY_RCU && !CLASSIC_SRCU + help + This option selects the single-CPU non-preemptible version of SRCU. + +config TREE_SRCU + bool + default y if !TINY_RCU && !CLASSIC_SRCU + help + This option selects the full-fledged version of SRCU. + config TASKS_RCU bool default n @@ -612,11 +641,17 @@ config RCU_FANOUT_LEAF initialization. These systems tend to run CPU-bound, and thus are not helped by synchronized interrupts, and thus tend to skew them, which reduces lock contention enough that large - leaf-level fanouts work well. + leaf-level fanouts work well. That said, setting leaf-level + fanout to a large number will likely cause problematic + lock contention on the leaf-level rcu_node structures unless + you boot with the skew_tick kernel parameter. Select a specific number if testing RCU itself. - Select the maximum permissible value for large systems. + Select the maximum permissible value for large systems, but + please understand that you may also need to set the skew_tick + kernel boot parameter to avoid contention on the rcu_node + structure's locks. Take the default if unsure. |