[PATCH 0/2] Move kfree_rcu out of rcu code and use kfree_bulk

From: rao . shoaib
Date: Tue Apr 03 2018 - 13:23:43 EST


From: Rao Shoaib <rao.shoaib@xxxxxxxxxx>

This patch moves kfree_call_rcu() out of rcu related code to
mm/slab_common and updates kfree_rcu() to use new bulk memory free
functions as they are more efficient.

This is a resubmission of the previous patch.

Changes since last submission
Surrounded code with 'CONFIG_TREE_RCU || CONFIG_PREEMPT_RCU'
to separate tinyurl definitions.

Diff of the changes:

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 6338fb6..102a93f 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -55,8 +55,6 @@ void call_rcu(struct rcu_head *head, rcu_callback_t func);
#define call_rcu call_rcu_sched
#endif /* #else #ifdef CONFIG_PREEMPT_RCU */

-/* only for use by kfree_call_rcu() */
-void call_rcu_lazy(struct rcu_head *head, rcu_callback_t func);

void call_rcu_bh(struct rcu_head *head, rcu_callback_t func);
void call_rcu_sched(struct rcu_head *head, rcu_callback_t func);
@@ -210,6 +208,8 @@ do { \

#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU)
#include <linux/rcutree.h>
+/* only for use by kfree_call_rcu() */
+void call_rcu_lazy(struct rcu_head *head, rcu_callback_t func);
#elif defined(CONFIG_TINY_RCU)
#include <linux/rcutiny.h>
#else
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 6e8afff..f126d08 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1526,6 +1526,7 @@ void kzfree(const void *p)
}
EXPORT_SYMBOL(kzfree);

+#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU)
static DEFINE_PER_CPU(struct rcu_bulk_free, cpu_rbf);

/* drain if atleast these many objects */
@@ -1696,6 +1697,7 @@ void kfree_call_rcu(struct rcu_head *head,
__rcu_bulk_free(head, func);
}
EXPORT_SYMBOL_GPL(kfree_call_rcu);
+#endif

Previous Changes:

1) checkpatch.pl has been fixed, so kfree_rcu macro is much simpler

2) To handle preemption, preempt_enable()/preempt_disable() statements
have been added to __rcu_bulk_free().

Rao Shoaib (2):
Move kfree_call_rcu() to slab_common.c
kfree_rcu() should use kfree_bulk() interface

include/linux/mm.h | 5 ++
include/linux/rcupdate.h | 43 +-----------
include/linux/rcutiny.h | 8 ++-
include/linux/rcutree.h | 2 -
include/linux/slab.h | 42 ++++++++++++
kernel/rcu/tree.c | 24 +++----
kernel/sysctl.c | 40 +++++++++++
mm/slab.h | 23 +++++++
mm/slab_common.c | 174 +++++++++++++++++++++++++++++++++++++++++++++++
9 files changed, 304 insertions(+), 57 deletions(-)

--
2.7.4