diff mbox series

[6/8] rcu/kvfree: Do not run a page work if a cache is disabled

Message ID 20230510170242.2187714-6-paulmck@kernel.org (mailing list archive)
State Mainlined
Commit 021a5ff8474379cd6c23e9b0e97aa27e5ff66a8b
Headers show
Series kvfree_rcu() changes for v6.5 | expand

Commit Message

Paul E. McKenney May 10, 2023, 5:02 p.m. UTC 
From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>

By default the cache size is 5 pages per CPU, but it can be disabled at
boot time by setting the rcu_min_cached_objs to zero.  When that happens,
the current code will uselessly set an hrtimer to schedule refilling this
cache with zero pages.  This commit therefore streamlines this process
by simply refusing the set the hrtimer when rcu_min_cached_objs is zero.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/tree.c | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 51d84eabf645..18f592bf6dc6 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3225,6 +3225,10 @@  static void fill_page_cache_func(struct work_struct *work)
 static void
 run_page_cache_worker(struct kfree_rcu_cpu *krcp)
 {
+	// If cache disabled, bail out.
+	if (!rcu_min_cached_objs)
+		return;
+
 	if (rcu_scheduler_active == RCU_SCHEDULER_RUNNING &&
 			!atomic_xchg(&krcp->work_in_progress, 1)) {
 		if (atomic_read(&krcp->backoff_page_cache_fill)) {