linux-kernel - [PATCH 09/18] rcu/tree: Simplify KFREE_BULK_MAX

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Date:   Sun, 29 Mar 2020 22:32:39 -0400
From:   "Joel Fernandes (Google)" <joel@...lfernandes.org>
To:     linux-kernel@...r.kernel.org
Cc:     "Uladzislau Rezki (Sony)" <urezki@...il.com>,
        Boqun Feng <boqun.feng@...il.com>,
        Joel Fernandes <joel@...lfernandes.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Ingo Molnar <mingo@...hat.com>,
        Josh Triplett <josh@...htriplett.org>,
        Lai Jiangshan <jiangshanlai@...il.com>, linux-mm@...ck.org,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        rcu@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>
Subject: [PATCH 09/18] rcu/tree: Simplify KFREE_BULK_MAX_ENTR macro

From: "Uladzislau Rezki (Sony)" <urezki@...il.com>

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@...il.com>
Reviewed-by: Joel Fernandes (Google) <joel@...lfernandes.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
Signed-off-by: Joel Fernandes (Google) <joel@...lfernandes.org>
---
 kernel/rcu/tree.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8dfa4b32e4d00..cfe456e68c644 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2807,13 +2807,6 @@ 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
@@ -2827,6 +2820,14 @@ struct kfree_rcu_bulk_data {
 	struct kfree_rcu_bulk_data *next;
 };
 
+/*
+ * 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
-- 
2.26.0.rc2.310.g2932bb562d-goog