Lines Matching full:rcu

8 This document describes RCU's expedited grace periods.
9 Unlike RCU's normal grace periods, which accept long latencies to attain
13 There are two flavors of RCU (RCU-preempt and RCU-sched), with an earlier
14 third RCU-bh flavor having been implemented in terms of the other two.
20 The expedited RCU grace periods cannot be accused of being subtle,
31 As always for RCU, once everything has spent some time in a quiescent
35 operation depend on the RCU flavor, as described in the following
38 RCU-preempt Expedited Grace Periods
41 ``CONFIG_PREEMPTION=y`` kernels implement RCU-preempt.
42 The overall flow of the handling of a given CPU by an RCU-preempt
58 However, because this is preemptible RCU, ``rcu_exp_handler()``
59 can check to see if the CPU is currently running in an RCU read-side
65 CPUs that might have RCU read-side critical sections.
69 Again because this is preemptible RCU, an RCU read-side critical section
71 When that happens, RCU will enqueue the task, which will the continue to
92 | Because we want the RCU read-side critical sections to run fast,      |
102 | these IPIs is to build your kernel with ``CONFIG_NO_HZ_FULL=y``. RCU  |
112 RCU-sched Expedited Grace Periods
115 ``CONFIG_PREEMPTION=n`` kernels implement RCU-sched. The overall flow of
116 the handling of a given CPU by an RCU-sched expedited grace period is
121 As with RCU-preempt, RCU-sched's ``synchronize_rcu_expedited()`` ignores
126 an RCU read-side critical section. The best that RCU-sched's
152    have ever been online at the beginning of an RCU expedited grace
159    beginning of the most recent RCU expedited grace period. The
163    field has changed since the beginning of the last RCU expedited grace
168    RCU expedited grace period. This means that only those CPUs that have
176 #. For each non-idle CPU that RCU believes is currently online, the
183 #. In the case of RCU-sched, one of the last acts of an outgoing CPU is
231 For RCU-sched, there is an additional check: If the IPI has interrupted
235 For RCU-preempt, there is no specific check for idle in the IPI handler
236 (``rcu_exp_handler()``), but because RCU read-side critical sections are
238 the CPU is within RCU read-side critical section, the CPU cannot
244 In summary, RCU expedited grace periods check for idle when building the
434 Expediting grace periods does nothing to speed things up when RCU
454 RCU CPU stall-warning time. If this time is exceeded, any CPUs or
507 idle CPUs, at least in the common case. RCU-preempt and RCU-sched use