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| author |   Waiman Long <longman@redhat.com> | 2021-08-26 22:21:22 -0400 |
|---|---|---|
| committer |   Paul E. McKenney <paulmck@kernel.org> | 2021-09-16 10:24:05 -0700 |
| commit | 925da92ba5cb0c82d07cdd5049a07e40f54e9c44 (patch) | |
| tree | d08eedefce6c6633753798c3ee93fbc02b63b3b9 /tools/perf/scripts/python/export-to-sqlite.py | |
| parent | rcu: Fix existing exp request check in sync_sched_exp_online_cleanup() (diff) | |
| download | wireguard-linux-925da92ba5cb0c82d07cdd5049a07e40f54e9c44.tar.xz wireguard-linux-925da92ba5cb0c82d07cdd5049a07e40f54e9c44.zip | |
rcu: Avoid unneeded function call in rcu_read_unlock()
Since commit aa40c138cc8f3 ("rcu: Report QS for outermost PREEMPT=n
rcu_read_unlock() for strict GPs") the function rcu_read_unlock_strict()
is invoked by the inlined rcu_read_unlock() function. However,
rcu_read_unlock_strict() is an empty function in production kernels,
which are built with CONFIG_RCU_STRICT_GRACE_PERIOD=n.
There is a mention of rcu_read_unlock_strict() in the BPF verifier,
but this is in a deny-list, meaning that BPF does not care whether
rcu_read_unlock_strict() is ever called.
This commit therefore provides a slight performance improvement
by hoisting the check of CONFIG_RCU_STRICT_GRACE_PERIOD from
rcu_read_unlock_strict() into rcu_read_unlock(), thus avoiding the
pointless call to an empty function.
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to '')
0 files changed, 0 insertions, 0 deletions