linux-kernel - [tip: core/rcu] rcu/tree: Simplify KFREE_BULK_MAX

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Date:   Fri, 31 Jul 2020 09:23:21 -0000
From:   "tip-bot2 for Uladzislau Rezki (Sony)" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Boqun Feng <boqun.feng@...il.com>,
        "Joel Fernandes (Google)" <joel@...lfernandes.org>,
        "Uladzislau Rezki (Sony)" <urezki@...il.com>,
        "Paul E. McKenney" <paulmck@...nel.org>, x86 <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [tip: core/rcu] rcu/tree: Simplify KFREE_BULK_MAX_ENTR macro

The following commit has been merged into the core/rcu branch of tip:

Commit-ID:     3af84862817403d317dc33312e7a88d76e79401a
Gitweb:        https://git.kernel.org/tip/3af84862817403d317dc33312e7a88d76e79401a
Author:        Uladzislau Rezki (Sony) <urezki@...il.com>
AuthorDate:    Mon, 25 May 2020 23:47:49 +02:00
Committer:     Paul E. McKenney <paulmck@...nel.org>
CommitterDate: Mon, 29 Jun 2020 11:59:25 -07:00

rcu/tree: Simplify KFREE_BULK_MAX_ENTR macro

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>
Signed-off-by: Paul E. McKenney <paulmck@...nel.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 143c1e9..bcdc063 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2958,13 +2958,6 @@ 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
@@ -2973,10 +2966,18 @@ 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