diff options
| author | Vlastimil Babka <vbabka@suse.cz> | 2025-02-03 10:28:50 +0100 |
|---|---|---|
| committer | Vlastimil Babka <vbabka@suse.cz> | 2025-02-05 10:45:35 +0100 |
| commit | c9f8f1242a4c3e48adc6c3cf6b31c1ffbaa49943 (patch) | |
| tree | ce7329b9e2f9368e30c44b04fe64cc6765d419d3 | |
| parent | 49d5377b38aa127451cf5dc6d6ea5d9da7f465a4 (diff) | |
slab: don't batch kvfree_rcu() with SLUB_TINY
kvfree_rcu() is batched for better performance except on TINY_RCU, which
is a simple implementation for small UP systems. Similarly SLUB_TINY is
an option intended for small systems, whether or not used together with
TINY_RCU. In case SLUB_TINY is used with !TINY_RCU, it makes arguably
sense to not do the batching and limit the memory footprint. It's also
suboptimal to have RCU-specific #ifdefs in slab code.
With that, add CONFIG_KVFREE_RCU_BATCHED to determine whether batching
kvfree_rcu() implementation is used. It is not set by a user prompt, but
enabled by default and disabled in case TINY_RCU or SLUB_TINY are
enabled.
Use the new config for #ifdef's in slab code and extend their scope to
cover all code used by the batched kvfree_rcu(). For example there's no
need to perform kvfree_rcu_init() if the batching is disabled.
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
| -rw-r--r-- | include/linux/slab.h | 2 | ||||
| -rw-r--r-- | mm/Kconfig | 4 | ||||
| -rw-r--r-- | mm/slab_common.c | 15 |
3 files changed, 14 insertions, 7 deletions
diff --git a/include/linux/slab.h b/include/linux/slab.h index bcc62e5656c3..7686054dd494 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -1083,7 +1083,7 @@ extern void kvfree_sensitive(const void *addr, size_t len); unsigned int kmem_cache_size(struct kmem_cache *s); -#ifdef CONFIG_TINY_RCU +#ifndef CONFIG_KVFREE_RCU_BATCHED static inline void kvfree_rcu_barrier(void) { rcu_barrier(); diff --git a/mm/Kconfig b/mm/Kconfig index 1b501db06417..0b7f4bb5cb80 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -242,6 +242,10 @@ menu "Slab allocator options" config SLUB def_bool y +config KVFREE_RCU_BATCHED + def_bool y + depends on !SLUB_TINY && !TINY_RCU + config SLUB_TINY bool "Configure for minimal memory footprint" depends on EXPERT diff --git a/mm/slab_common.c b/mm/slab_common.c index 6438a38aa5dc..46d0a4cd33b5 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -1284,7 +1284,7 @@ EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); EXPORT_TRACEPOINT_SYMBOL(kfree); EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); -#ifdef CONFIG_TINY_RCU +#ifndef CONFIG_KVFREE_RCU_BATCHED void kvfree_call_rcu(struct rcu_head *head, void *ptr) { @@ -1301,7 +1301,11 @@ void kvfree_call_rcu(struct rcu_head *head, void *ptr) } EXPORT_SYMBOL_GPL(kvfree_call_rcu); -#endif +void __init kvfree_rcu_init(void) +{ +} + +#else /* CONFIG_KVFREE_RCU_BATCHED */ /* * This rcu parameter is runtime-read-only. It reflects @@ -1879,8 +1883,6 @@ add_ptr_to_bulk_krc_lock(struct kfree_rcu_cpu **krcp, return true; } -#if !defined(CONFIG_TINY_RCU) - static enum hrtimer_restart schedule_page_work_fn(struct hrtimer *t) { @@ -2089,8 +2091,6 @@ void kvfree_rcu_barrier(void) } EXPORT_SYMBOL_GPL(kvfree_rcu_barrier); -#endif /* #if !defined(CONFIG_TINY_RCU) */ - static unsigned long kfree_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc) { @@ -2180,3 +2180,6 @@ void __init kvfree_rcu_init(void) shrinker_register(kfree_rcu_shrinker); } + +#endif /* CONFIG_KVFREE_RCU_BATCHED */ + |