kfence: allow use of a deferrable timer

[linux-block.git] / mm / kfence / core.c

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index f126b53b9b8567e7e64f23dea69c26907f2828ed..2f9fdfde19416a1c271b3c45c7f1405807e84f77 100644 (file)
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -95,6 +95,10 @@ module_param_cb(sample_interval, &sample_interval_param_ops, &kfence_sample_inte
 static unsigned long kfence_skip_covered_thresh __read_mostly = 75;
 module_param_named(skip_covered_thresh, kfence_skip_covered_thresh, ulong, 0644);
 
+/* If true, use a deferrable timer. */
+static bool kfence_deferrable __read_mostly = IS_ENABLED(CONFIG_KFENCE_DEFERRABLE);
+module_param_named(deferrable, kfence_deferrable, bool, 0444);
+
 /* The pool of pages used for guard pages and objects. */
 char *__kfence_pool __read_mostly;
 EXPORT_SYMBOL(__kfence_pool); /* Export for test modules. */
@@ -740,6 +744,8 @@ late_initcall(kfence_debugfs_init);
 
 /* === Allocation Gate Timer ================================================ */
 
+static struct delayed_work kfence_timer;
+
 #ifdef CONFIG_KFENCE_STATIC_KEYS
 /* Wait queue to wake up allocation-gate timer task. */
 static DECLARE_WAIT_QUEUE_HEAD(allocation_wait);
@@ -762,7 +768,6 @@ static DEFINE_IRQ_WORK(wake_up_kfence_timer_work, wake_up_kfence_timer);
  * avoids IPIs, at the cost of not immediately capturing allocations if the
  * instructions remain cached.
  */
-static struct delayed_work kfence_timer;
 static void toggle_allocation_gate(struct work_struct *work)
 {
        if (!READ_ONCE(kfence_enabled))
@@ -790,7 +795,6 @@ static void toggle_allocation_gate(struct work_struct *work)
        queue_delayed_work(system_unbound_wq, &kfence_timer,
                           msecs_to_jiffies(kfence_sample_interval));
 }
-static DECLARE_DELAYED_WORK(kfence_timer, toggle_allocation_gate);
 
 /* === Public interface ===================================================== */
 
@@ -809,8 +813,15 @@ static void kfence_init_enable(void)
 {
        if (!IS_ENABLED(CONFIG_KFENCE_STATIC_KEYS))
                static_branch_enable(&kfence_allocation_key);
+
+       if (kfence_deferrable)
+               INIT_DEFERRABLE_WORK(&kfence_timer, toggle_allocation_gate);
+       else
+               INIT_DELAYED_WORK(&kfence_timer, toggle_allocation_gate);
+
        WRITE_ONCE(kfence_enabled, true);
        queue_delayed_work(system_unbound_wq, &kfence_timer, 0);
+
        pr_info("initialized - using %lu bytes for %d objects at 0x%p-0x%p\n", KFENCE_POOL_SIZE,
                CONFIG_KFENCE_NUM_OBJECTS, (void *)__kfence_pool,
                (void *)(__kfence_pool + KFENCE_POOL_SIZE));