Re: [PATCH 18/24] mm/list_lru.c: Remove kvfree_rcu_local() function

[Uladzislau Rezki <urezki@xxxxxxxxx>]

Hello.

I apologize. Please ignore this patch and email. Wanted to send it to one person,

instead git send-email also handled some emails from commit footer.

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Vlad Rezki

On Mon, Apr 27, 2020 at 1:11 PM Uladzislau Rezki (Sony) <urezki@xxxxxxxxx> wrote:

Since there is newly introduced kvfree_rcu() API, there is no need in
queuing and using call_rcu() to kvfree() an object after the GP.

Remove kvfree_rcu_local() function and replace call_rcu() by new
kvfree_rcu() API that does the same but in more efficient way.

Cc: linux-mm@xxxxxxxxx
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: rcu@xxxxxxxxxxxxxxx
Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Reviewed-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
---
 mm/list_lru.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/mm/list_lru.c b/mm/list_lru.c
index 42c95bcb53ca..a0b08b27a9b9 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -12,6 +12,7 @@
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/memcontrol.h>
+#include <linux/rcupdate.h>
 #include "slab.h"

 #ifdef CONFIG_MEMCG_KMEM
@@ -373,21 +374,13 @@ static void memcg_destroy_list_lru_node(struct list_lru_node *nlru)
        struct list_lru_memcg *memcg_lrus;
        /*
         * This is called when shrinker has already been unregistered,
-        * and nobody can use it. So, there is no need to use kvfree_rcu_local().
+        * and nobody can use it. So, there is no need to use kvfree_rcu().
         */
        memcg_lrus = rcu_dereference_protected(nlru->memcg_lrus, true);
        __memcg_destroy_list_lru_node(memcg_lrus, 0, memcg_nr_cache_ids);
        kvfree(memcg_lrus);
 }

-static void kvfree_rcu_local(struct rcu_head *head)
-{
-       struct list_lru_memcg *mlru;
-
-       mlru = container_of(head, struct list_lru_memcg, rcu);
-       kvfree(mlru);
-}
-
 static int memcg_update_list_lru_node(struct list_lru_node *nlru,
                                      int old_size, int new_size)
 {
@@ -419,7 +412,7 @@ static int memcg_update_list_lru_node(struct list_lru_node *nlru,
        rcu_assign_pointer(nlru->memcg_lrus, new);
        spin_unlock_irq(&nlru->lock);

-       call_rcu(&old->rcu, kvfree_rcu_local);
+       kvfree_rcu(old, rcu);
        return 0;
 }

--
2.20.1

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Uladzislau Rezki