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| author | Waiman Long <[email protected]> | 2021-08-27 02:21:22 +0000 |
|---|---|---|
| committer | Paul E. McKenney <[email protected]> | 2021-09-16 17:24:05 +0000 |
| commit | 925da92ba5cb0c82d07cdd5049a07e40f54e9c44 (patch) | |
| tree | d08eedefce6c6633753798c3ee93fbc02b63b3b9 /scripts/gcc-plugins/gcc-common.h | |
| parent | rcu: Fix existing exp request check in sync_sched_exp_online_cleanup() (diff) | |
| download | kernel-925da92ba5cb0c82d07cdd5049a07e40f54e9c44.tar.gz kernel-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 <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Waiman Long <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Diffstat (limited to 'scripts/gcc-plugins/gcc-common.h')
0 files changed, 0 insertions, 0 deletions