rcuscale: Count outstanding callbacks per-task rather than per-CPU

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The current rcu_scale_writer() asynchronous grace-period testing uses a
per-CPU counter to track the number of outstanding callbacks.  This is
subject to CPU-imbalance errors when tasks migrate from one CPU to another
between the time that the counter is incremented and the callback is
queued, and additionally in kernels configured such that callbacks can
be invoked on some CPU other than the one that queued it.

This commit therefore arranges for per-task callback counts, thus avoiding
any issues with migration of either tasks or callbacks.

Reported-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>

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Paul E. McKenney 2024-08-01 17:43:08 -07:00 • committed by Neeraj Upadhyay

parent 554f07a119

commit f1fd0e0bb1

1 changed files with 6 additions and 4 deletions

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kernel/rcu/rcuscale.c

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