[PATCH v2 05/16] rcu/tree: Simplify KFREE_BULK_MAX_ENTR macro

Uladzislau Rezki (Sony)
2020-05-25T21:48:26Z

We can simplify KFREE_BULK_MAX_ENTR macro and get rid of
magic numbers which were used to make the structure to be
exactly one page.

Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
kernel/rcu/tree.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 776ccf858154..6501fbcae3c7 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2824,13 +2824,6 @@ EXPORT_SYMBOL_GPL(call_rcu);
#define KFREE_DRAIN_JIFFIES (HZ / 50)
#define KFREE_N_BATCHES 2

-/*
- * This macro defines how many entries the "records" array
- * will contain. It is based on the fact that the size of
- * kfree_rcu_bulk_data structure becomes exactly one page.
- */
-#define KFREE_BULK_MAX_ENTR ((PAGE_SIZE / sizeof(void *)) - 3)
-
/**
* struct kfree_rcu_bulk_data - single block to store kfree_rcu() pointers
* @nr_records: Number of active pointers in the array
@@ -2839,10 +2832,18 @@ EXPORT_SYMBOL_GPL(call_rcu);
*/
struct kfree_rcu_bulk_data {
unsigned long nr_records;
- void *records[KFREE_BULK_MAX_ENTR];
struct kfree_rcu_bulk_data *next;
+ void *records[];
};

+/*
+ * This macro defines how many entries the "records" array
+ * will contain. It is based on the fact that the size of
+ * kfree_rcu_bulk_data structure becomes exactly one page.
+ */
+#define KFREE_BULK_MAX_ENTR \
+ ((PAGE_SIZE - sizeof(struct kfree_rcu_bulk_data)) / sizeof(void *))
+
/**
* struct kfree_rcu_cpu_work - single batch of kfree_rcu() requests
* @rcu_work: Let queue_rcu_work() invoke workqueue handler after grace period
--
2.20.1