Messages in this thread | | | Date | Thu, 19 Feb 2015 21:08:50 -0800 | From | "Paul E. McKenney" <> | Subject | [PATCH tip/core/rcu 0/4] Programmatic nestable expedited grace periods |
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Hello!
This series, possibly for v3.21, contains changes that allow in-kernel code to specify that all subsequent synchronous grace-period primitives (synchronize_rcu() and friends) be expedited. New rcu_expedite_gp() and rcu_unexpedite_gp() primitives enable and disable expediting, and these may be nested. Note that the rcu_expedited boot/sysfs variable, if non-zero, causes expediting to happen regardless of calls to rcu_expedite_gp().
Because one of the use cases for these primitives is to expedite grace periods during the in-kernel portion of boot, a new Kconfig parameter named CONFIG_RCU_EXPEDITE_BOOT causes the kernel to act as if rcu_expedite_gp() was called very early in boot. At the end of boot (presumably just before init is spawned), a call to rcu_end_inkernel_boot() will provide the matching rcu_unexpedite_gp() if required.
The patches in this series are as follows:
1. Add rcu_expedite_gp() and rcu_unexpedite_gp() functions.
2. Add rcutorture tests for rcu_expedite_gp() and rcu_unexpedite_gp().
3. Change open-coded access to the rcu_expedited variable to instead use a new rcu_gp_is_expedited() function.
4. Add the CONFIG_RCU_EXPEDITE_BOOT Kconfig parameter and the rcu_end_inkernel_boot() function.
This passes light rcutorture testing.
Thanx, Paul
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b/include/linux/rcupdate.h | 21 ++++++++++++++++ b/init/Kconfig | 13 +++++++++ b/kernel/rcu/rcutorture.c | 24 ++++++++++++++++++ b/kernel/rcu/srcu.c | 2 - b/kernel/rcu/tree.c | 9 +++--- b/kernel/rcu/tree_plugin.h | 2 - b/kernel/rcu/update.c | 59 ++++++++++++++++++++++++++++++++++++++++++++- 7 files changed, 123 insertions(+), 7 deletions(-)
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