c34fa06f4b
Currently rcu_preempt_deferred_qs_irqrestore() releases rnp->boost_mtx before reporting the expedited quiescent state. Under heavy real-time load, this can result in this function being preempted before the quiescent state is reported, which can in turn prevent the expedited grace period from completing. Tim Murray reports that the resulting expedited grace periods can take hundreds of milliseconds and even more than one second, when they should normally complete in less than a millisecond. This patch follows Neeraj's suggestion (seconded by Tim and by Uladzislau Rezki) of simply reversing the two operations. Reported-by: Tim Murray <timmurray@google.com> Reported-by: Joel Fernandes <joelaf@google.com> Reported-by: Neeraj Upadhyay <quic_neeraju@quicinc.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Bug: 217236054 Link: https://lore.kernel.org/lkml/20220204232406.814-9-paulmck@kernel.org/ Signed-off-by: Tim Murray <timmurray@google.com> Change-Id: Ic0f0330b65a0c776a563e03e4b59bf4ab4fbccf6 |
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| .. | ||
| Kconfig | ||
| Kconfig.debug | ||
| Makefile | ||
| rcu.h | ||
| rcu_segcblist.c | ||
| rcu_segcblist.h | ||
| rcuscale.c | ||
| rcutorture.c | ||
| refscale.c | ||
| srcutiny.c | ||
| srcutree.c | ||
| sync.c | ||
| tasks.h | ||
| tiny.c | ||
| tree.c | ||
| tree.h | ||
| tree_exp.h | ||
| tree_plugin.h | ||
| tree_stall.h | ||
| update.c | ||