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| author |  Zqiang <qiang1.zhang@intel.com>
| 2023-01-30 15:17:37 +0800 |
|---|---|---|
| committer |  Joel Fernandes (Google) <joel@joelfernandes.org>
| 2023-04-05 13:47:43 +0000 |
| commit | 2450b78e0bb1e034eaa2a33dca689282bd8c892a (patch) | |
| tree | d289de27675ab21ee8a723e069252e5cf7b0d2b1 /kernel/rcu | |
| parent | rcu: Fix missing TICK_DEP_MASK_RCU_EXP dependency check (diff) | |
| download | linux-2450b78e0bb1e034eaa2a33dca689282bd8c892a.tar.gz linux-2450b78e0bb1e034eaa2a33dca689282bd8c892a.tar.bz2 linux-2450b78e0bb1e034eaa2a33dca689282bd8c892a.zip | |
rcu: Register rcu-lazy shrinker only for CONFIG_RCU_LAZY=y kernels
The lazy_rcu_shrink_count() shrinker function is registered even in
kernels built with CONFIG_RCU_LAZY=n, in which case this function
uselessly consumes cycles learning that no CPU has any lazy callbacks
queued.
This commit therefore registers this shrinker function only in the kernels
built with CONFIG_RCU_LAZY=y, where it might actually do something useful.
Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree_nocb.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h index 9e1c8caec5ce..f2280616f9d5 100644 --- a/kernel/rcu/tree_nocb.h +++ b/kernel/rcu/tree_nocb.h @@ -1312,6 +1312,7 @@ int rcu_nocb_cpu_offload(int cpu) } EXPORT_SYMBOL_GPL(rcu_nocb_cpu_offload); +#ifdef CONFIG_RCU_LAZY static unsigned long lazy_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc) { @@ -1360,6 +1361,7 @@ static struct shrinker lazy_rcu_shrinker = { .batch = 0, .seeks = DEFAULT_SEEKS, }; +#endif // #ifdef CONFIG_RCU_LAZY void __init rcu_init_nohz(void) { @@ -1391,8 +1393,10 @@ void __init rcu_init_nohz(void) if (!rcu_state.nocb_is_setup) return; +#ifdef CONFIG_RCU_LAZY if (register_shrinker(&lazy_rcu_shrinker, "rcu-lazy")) pr_err("Failed to register lazy_rcu shrinker!\n"); +#endif // #ifdef CONFIG_RCU_LAZY if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) { pr_info("\tNote: kernel parameter 'rcu_nocbs=', 'nohz_full', or 'isolcpus=' contains nonexistent CPUs.\n"); |