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From: js1304@gmail.com
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>,
	Pekka Enberg <penberg@kernel.org>,
	David Rientjes <rientjes@google.com>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: [PATCH 02/11] mm/slab: remove BAD_ALIEN_MAGIC again
Date: Mon, 28 Mar 2016 14:26:52 +0900	[thread overview]
Message-ID: <1459142821-20303-3-git-send-email-iamjoonsoo.kim@lge.com> (raw)
In-Reply-To: <1459142821-20303-1-git-send-email-iamjoonsoo.kim@lge.com>

From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Initial attemp to remove BAD_ALIEN_MAGIC is once reverted by
'commit edcad2509550 ("Revert "slab: remove BAD_ALIEN_MAGIC"")'
because it causes a problem on m68k which has many node
but !CONFIG_NUMA. In this case, although alien cache isn't used
at all but to cope with some initialization path, garbage value
is used and that is BAD_ALIEN_MAGIC. Now, this patch set
use_alien_caches to 0 when !CONFIG_NUMA, there is no initialization
path problem so we don't need BAD_ALIEN_MAGIC at all. So remove it.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
 mm/slab.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 043606a..a5a205b 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -421,8 +421,6 @@ static struct kmem_cache kmem_cache_boot = {
 	.name = "kmem_cache",
 };
 
-#define BAD_ALIEN_MAGIC 0x01020304ul
-
 static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
 
 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
@@ -637,7 +635,7 @@ static int transfer_objects(struct array_cache *to,
 static inline struct alien_cache **alloc_alien_cache(int node,
 						int limit, gfp_t gfp)
 {
-	return (struct alien_cache **)BAD_ALIEN_MAGIC;
+	return NULL;
 }
 
 static inline void free_alien_cache(struct alien_cache **ac_ptr)
@@ -1205,7 +1203,7 @@ void __init kmem_cache_init(void)
 					sizeof(struct rcu_head));
 	kmem_cache = &kmem_cache_boot;
 
-	if (num_possible_nodes() == 1)
+	if (!IS_ENABLED(CONFIG_NUMA) || num_possible_nodes() == 1)
 		use_alien_caches = 0;
 
 	for (i = 0; i < NUM_INIT_LISTS; i++)
-- 
1.9.1

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  parent reply	other threads:[~2016-03-28  5:27 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-28  5:26 mm/slab: reduce lock contention in alloc path js1304
2016-03-28  5:26 ` [PATCH 01/11] mm/slab: hold a slab_mutex when calling __kmem_cache_shrink() js1304
2016-03-29  0:50   ` Christoph Lameter
2016-03-30  8:11     ` Joonsoo Kim
2016-03-31 10:53   ` Nikolay Borisov
2016-04-01  2:18     ` Joonsoo Kim
2016-03-28  5:26 ` js1304 [this message]
2016-03-28  8:58   ` [PATCH 02/11] mm/slab: remove BAD_ALIEN_MAGIC again Geert Uytterhoeven
2016-03-30  8:11     ` Joonsoo Kim
2016-03-28 21:19   ` Andrew Morton
2016-03-29  0:53     ` Christoph Lameter
2016-03-28  5:26 ` [PATCH 03/11] mm/slab: drain the free slab as much as possible js1304
2016-03-29  0:54   ` Christoph Lameter
2016-03-28  5:26 ` [PATCH 04/11] mm/slab: factor out kmem_cache_node initialization code js1304
2016-03-29  0:56   ` Christoph Lameter
2016-03-30  8:12     ` Joonsoo Kim
2016-03-28  5:26 ` [PATCH 05/11] mm/slab: clean-up kmem_cache_node setup js1304
2016-03-29  0:58   ` Christoph Lameter
2016-03-30  8:15     ` Joonsoo Kim
2016-03-28  5:26 ` [PATCH 06/11] mm/slab: don't keep free slabs if free_objects exceeds free_limit js1304
2016-03-29  1:03   ` Christoph Lameter
2016-03-30  8:25     ` Joonsoo Kim
2016-03-28  5:26 ` [PATCH 07/11] mm/slab: racy access/modify the slab color js1304
2016-03-29  1:05   ` Christoph Lameter
2016-03-30  8:25     ` Joonsoo Kim
2016-03-28  5:26 ` [PATCH 08/11] mm/slab: make cache_grow() handle the page allocated on arbitrary node js1304
2016-03-28  5:26 ` [PATCH 09/11] mm/slab: separate cache_grow() to two parts js1304
2016-03-28  5:27 ` [PATCH 10/11] mm/slab: refill cpu cache through a new slab without holding a node lock js1304
2016-03-28  5:27 ` [PATCH 11/11] mm/slab: lockless decision to grow cache js1304

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