linux-kernel - [PATCH v2 01/29] slab: dup name string

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Message-Id: <1336758272-24284-2-git-send-email-glommer@parallels.com>
Date:	Fri, 11 May 2012 14:44:03 -0300
From:	Glauber Costa <glommer@...allels.com>
To:	<linux-kernel@...r.kernel.org>
Cc:	<cgroups@...r.kernel.org>, <linux-mm@...ck.org>,
	<kamezawa.hiroyu@...fujitsu.com>, Tejun Heo <tj@...nel.org>,
	Li Zefan <lizefan@...wei.com>,
	Greg Thelen <gthelen@...gle.com>,
	Suleiman Souhlal <suleiman@...gle.com>,
	Michal Hocko <mhocko@...e.cz>,
	Johannes Weiner <hannes@...xchg.org>, <devel@...nvz.org>,
	Glauber Costa <glommer@...allels.com>,
	Christoph Lameter <cl@...ux.com>,
	Pekka Enberg <penberg@...helsinki.fi>
Subject: [PATCH v2 01/29] slab: dup name string

The slub allocator creates a copy of the name string, and
frees it later. I would like them both to behave the same,
whether it is the slab starting to create a copy of it itself,
or the slub ceasing to.

This is because when I create memcg copies of it, I have to
kmalloc strings for the new names, and having the allocators to
behave differently here, would make it a lot uglier.

My first submission removed the duplication for the slub. But
the code started to get a bit complicated when dealing with
deletion of chained caches. Also, Christoph voiced his opinion
that patching the slab to keep copies would be better.

So here it is.

Signed-off-by: Glauber Costa <glommer@...allels.com>
CC: Christoph Lameter <cl@...ux.com>
CC: Pekka Enberg <penberg@...helsinki.fi>
---
 mm/slab.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index e901a36..91b9c13 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2118,6 +2118,7 @@ static void __kmem_cache_destroy(struct kmem_cache *cachep)
 			kfree(l3);
 		}
 	}
+	kfree(cachep->name);
 	kmem_cache_free(&cache_cache, cachep);
 }
 
@@ -2526,7 +2527,7 @@ kmem_cache_create (const char *name, size_t size, size_t align,
 		BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache));
 	}
 	cachep->ctor = ctor;
-	cachep->name = name;
+	cachep->name = kstrdup(name, GFP_KERNEL);
 
 	if (setup_cpu_cache(cachep, gfp)) {
 		__kmem_cache_destroy(cachep);
-- 
1.7.7.6

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