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36221e109e
Expedited RCU grace periods send IPIs to all non-idle CPUs, and thus can disrupt time-critical code in real-time applications. However, there is a portion of boot-time processing (presumably before any real-time applications have started) where expedited RCU grace periods are the only option. And so it is that experience with the -rt patchset indicates that PREEMPT_RT systems should always set the rcupdate.rcu_normal_after_boot kernel boot parameter. This commit therefore makes the post-boot application environment safe for real-time applications by making PREEMPT_RT systems disable the rcupdate.rcu_normal_after_boot kernel boot parameter and acting as if this parameter had been set. This means that post-boot calls to synchronize_rcu_expedited() will be treated as if they were instead calls to synchronize_rcu(), thus preventing the IPIs, and thus avoiding disrupting real-time applications. Suggested-by: Luiz Capitulino <lcapitulino@redhat.com> Acked-by: Paul E. McKenney <paulmck@linux.ibm.com> Signed-off-by: Julia Cartwright <julia@ni.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> [ paulmck: Update kernel-parameters.txt accordingly. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org> |
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| .. | ||
| Kconfig | ||
| Kconfig.debug | ||
| Makefile | ||
| rcu_segcblist.c | ||
| rcu_segcblist.h | ||
| rcu.h | ||
| rcuscale.c | ||
| rcutorture.c | ||
| refscale.c | ||
| srcutiny.c | ||
| srcutree.c | ||
| sync.c | ||
| tasks.h | ||
| tiny.c | ||
| tree_exp.h | ||
| tree_plugin.h | ||
| tree_stall.h | ||
| tree.c | ||
| tree.h | ||
| update.c | ||