Received-SPF: pass (google.com: domain of linux-kernel+bounces-62413-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Date: Mon, 12 Feb 2024 13:38:53 -0800
In-Reply-To: <20240212213922.783301-1-surenb@google.com>
Precedence: bulk
Mime-Version: 1.0
References: <20240212213922.783301-1-surenb@google.com>
Message-ID: <20240212213922.783301-8-surenb@google.com>
Subject: [PATCH v3 07/35] mm/slab: introduce SLAB_NO_OBJ_EXT to avoid obj_ext creation
From: Suren Baghdasaryan <surenb@google.com>
To: akpm@linux-foundation.org
Cc: kent.overstreet@linux.dev, mhocko@suse.com, vbabka@suse.cz, 
	hannes@cmpxchg.org, roman.gushchin@linux.dev, mgorman@suse.de, 
	dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, 
	corbet@lwn.net, void@manifault.com, peterz@infradead.org, 
	juri.lelli@redhat.com, catalin.marinas@arm.com, will@kernel.org, 
	arnd@arndb.de, tglx@linutronix.de, mingo@redhat.com, 
	dave.hansen@linux.intel.com, x86@kernel.org, peterx@redhat.com, 
	david@redhat.com, axboe@kernel.dk, mcgrof@kernel.org, masahiroy@kernel.org, 
	nathan@kernel.org, dennis@kernel.org, tj@kernel.org, muchun.song@linux.dev, 
	rppt@kernel.org, paulmck@kernel.org, pasha.tatashin@soleen.com, 
	yosryahmed@google.com, yuzhao@google.com, dhowells@redhat.com, 
	hughd@google.com, andreyknvl@gmail.com, keescook@chromium.org, 
	ndesaulniers@google.com, vvvvvv@google.com, gregkh@linuxfoundation.org, 
	ebiggers@google.com, ytcoode@gmail.com, vincent.guittot@linaro.org, 
	dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, 
	bristot@redhat.com, vschneid@redhat.com, cl@linux.com, penberg@kernel.org, 
	iamjoonsoo.kim@lge.com, 42.hyeyoo@gmail.com, glider@google.com, 
	elver@google.com, dvyukov@google.com, shakeelb@google.com, 
	songmuchun@bytedance.com, jbaron@akamai.com, rientjes@google.com, 
	minchan@google.com, kaleshsingh@google.com, surenb@google.com, 
	kernel-team@android.com, linux-doc@vger.kernel.org, 
	linux-kernel@vger.kernel.org, iommu@lists.linux.dev, 
	linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, 
	linux-modules@vger.kernel.org, kasan-dev@googlegroups.com, 
	cgroups@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"

Slab extension objects can't be allocated before slab infrastructure is
initialized. Some caches, like kmem_cache and kmem_cache_node, are created
before slab infrastructure is initialized. Objects from these caches can't
have extension objects. Introduce SLAB_NO_OBJ_EXT slab flag to mark these
caches and avoid creating extensions for objects allocated from these
slabs.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 include/linux/slab.h | 7 +++++++
 mm/slub.c            | 5 +++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index b5f5ee8308d0..3ac2fc830f0f 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -164,6 +164,13 @@
 #endif
 #define SLAB_TEMPORARY		SLAB_RECLAIM_ACCOUNT	/* Objects are short-lived */
 
+#ifdef CONFIG_SLAB_OBJ_EXT
+/* Slab created using create_boot_cache */
+#define SLAB_NO_OBJ_EXT         ((slab_flags_t __force)0x20000000U)
+#else
+#define SLAB_NO_OBJ_EXT         0
+#endif
+
 /*
  * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
  *
diff --git a/mm/slub.c b/mm/slub.c
index 1eb1050814aa..9fd96238ed39 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5650,7 +5650,8 @@ void __init kmem_cache_init(void)
 		node_set(node, slab_nodes);
 
 	create_boot_cache(kmem_cache_node, "kmem_cache_node",
-		sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
+			sizeof(struct kmem_cache_node),
+			SLAB_HWCACHE_ALIGN | SLAB_NO_OBJ_EXT, 0, 0);
 
 	hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
 
@@ -5660,7 +5661,7 @@ void __init kmem_cache_init(void)
 	create_boot_cache(kmem_cache, "kmem_cache",
 			offsetof(struct kmem_cache, node) +
 				nr_node_ids * sizeof(struct kmem_cache_node *),
-		       SLAB_HWCACHE_ALIGN, 0, 0);
+			SLAB_HWCACHE_ALIGN | SLAB_NO_OBJ_EXT, 0, 0);
 
 	kmem_cache = bootstrap(&boot_kmem_cache);
 	kmem_cache_node = bootstrap(&boot_kmem_cache_node);
-- 
2.43.0.687.g38aa6559b0-goog