diff mbox

kmem_cache_attr (was Re: [PATCH 04/36] usercopy: Prepare for usercopy whitelisting)

Message ID alpine.DEB.2.20.1801161215500.2945@nuc-kabylake (mailing list archive)
State Accepted, archived
Headers show

Commit Message

Christoph Lameter (Ampere) Jan. 16, 2018, 6:17 p.m. UTC
Draft patch of how the data structs could change. kmem_cache_attr is read
only.

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Comments

Matthew Wilcox Jan. 16, 2018, 9:03 p.m. UTC | #1
On Tue, Jan 16, 2018 at 12:17:01PM -0600, Christopher Lameter wrote:
> Draft patch of how the data structs could change. kmem_cache_attr is read
> only.

Looks good.  Although I would add Kees' user feature:

struct kmem_cache_attr {
	char name[16];
	unsigned int size;
	unsigned int align;
+	unsigned int useroffset;
+	unsigned int usersize;
	slab_flags_t flags;
	kmem_cache_ctor ctor;
}

And I'd start with 
+struct kmem_cache *kmem_cache_create_attr(const kmem_cache_attr *);

leaving the old kmem_cache_create to kmalloc a kmem_cache_attr and
initialise it.

Can we also do something like this?

-#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
-		sizeof(struct __struct), __alignof__(struct __struct),\
-		(__flags), NULL)
+#define KMEM_CACHE(__struct, __flags) ({				\
+	const struct kmem_cache_attr kca ## __stringify(__struct) = {	\
+		.name = #__struct,					\
+		.size = sizeof(struct __struct),			\
+		.align = __alignof__(struct __struct),			\
+		.flags = (__flags),					\
+	};								\
+	kmem_cache_create_attr(&kca ## __stringify(__struct));		\
+})

That way we won't need to convert any of those users.

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Christoph Lameter (Ampere) Jan. 17, 2018, 2:46 p.m. UTC | #2
On Tue, 16 Jan 2018, Matthew Wilcox wrote:

> On Tue, Jan 16, 2018 at 12:17:01PM -0600, Christopher Lameter wrote:
> > Draft patch of how the data structs could change. kmem_cache_attr is read
> > only.
>
> Looks good.  Although I would add Kees' user feature:

Sure I tried to do this quickly so that the basic struct changes are
visible.

> And I'd start with
> +struct kmem_cache *kmem_cache_create_attr(const kmem_cache_attr *);
>
> leaving the old kmem_cache_create to kmalloc a kmem_cache_attr and
> initialise it.

Well at some point we should convert the callers by putting the
definitions into const kmem_cache_attr initializations. That way
the callbacks function pointers are safe.

> Can we also do something like this?
>
> -#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
> -		sizeof(struct __struct), __alignof__(struct __struct),\
> -		(__flags), NULL)
> +#define KMEM_CACHE(__struct, __flags) ({				\
> +	const struct kmem_cache_attr kca ## __stringify(__struct) = {	\
> +		.name = #__struct,					\
> +		.size = sizeof(struct __struct),			\
> +		.align = __alignof__(struct __struct),			\
> +		.flags = (__flags),					\
> +	};								\
> +	kmem_cache_create_attr(&kca ## __stringify(__struct));		\
> +})
>
> That way we won't need to convert any of those users.

Yep thats what I was planning.

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diff mbox

Patch

Index: linux/include/linux/slab.h
===================================================================
--- linux.orig/include/linux/slab.h
+++ linux/include/linux/slab.h
@@ -135,9 +135,17 @@  struct mem_cgroup;
 void __init kmem_cache_init(void);
 bool slab_is_available(void);

-struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
-			slab_flags_t,
-			void (*)(void *));
+typedef kmem_cache_ctor void (*ctor)(void *);
+
+struct kmem_cache_attr {
+	char name[16];
+	unsigned int size;
+	unsigned int align;
+	slab_flags_t flags;
+	kmem_cache_ctor ctor;
+}
+
+struct kmem_cache *kmem_cache_create(const kmem_cache_attr *);
 void kmem_cache_destroy(struct kmem_cache *);
 int kmem_cache_shrink(struct kmem_cache *);

Index: linux/include/linux/slab_def.h
===================================================================
--- linux.orig/include/linux/slab_def.h
+++ linux/include/linux/slab_def.h
@@ -10,6 +10,7 @@ 

 struct kmem_cache {
 	struct array_cache __percpu *cpu_cache;
+	struct kmem_cache_attr *attr;

 /* 1) Cache tunables. Protected by slab_mutex */
 	unsigned int batchcount;
@@ -35,14 +36,9 @@  struct kmem_cache {
 	struct kmem_cache *freelist_cache;
 	unsigned int freelist_size;

-	/* constructor func */
-	void (*ctor)(void *obj);
-
 /* 4) cache creation/removal */
-	const char *name;
 	struct list_head list;
 	int refcount;
-	int object_size;
 	int align;

 /* 5) statistics */
Index: linux/include/linux/slub_def.h
===================================================================
--- linux.orig/include/linux/slub_def.h
+++ linux/include/linux/slub_def.h
@@ -83,9 +83,9 @@  struct kmem_cache {
 	struct kmem_cache_cpu __percpu *cpu_slab;
 	/* Used for retriving partial slabs etc */
 	slab_flags_t flags;
+	struct kmem_cache_attr *attr;
 	unsigned long min_partial;
 	int size;		/* The size of an object including meta data */
-	int object_size;	/* The size of an object without meta data */
 	int offset;		/* Free pointer offset. */
 #ifdef CONFIG_SLUB_CPU_PARTIAL
 	int cpu_partial;	/* Number of per cpu partial objects to keep around */
@@ -97,12 +97,10 @@  struct kmem_cache {
 	struct kmem_cache_order_objects min;
 	gfp_t allocflags;	/* gfp flags to use on each alloc */
 	int refcount;		/* Refcount for slab cache destroy */
-	void (*ctor)(void *);
 	int inuse;		/* Offset to metadata */
 	int align;		/* Alignment */
 	int reserved;		/* Reserved bytes at the end of slabs */
 	int red_left_pad;	/* Left redzone padding size */
-	const char *name;	/* Name (only for display!) */
 	struct list_head list;	/* List of slab caches */
 #ifdef CONFIG_SYSFS
 	struct kobject kobj;	/* For sysfs */
Index: linux/mm/slab.h
===================================================================
--- linux.orig/mm/slab.h
+++ linux/mm/slab.h
@@ -18,13 +18,11 @@ 
  * SLUB is no longer needed.
  */
 struct kmem_cache {
-	unsigned int object_size;/* The original size of the object */
+	struct kmem_cache_attr *attr
 	unsigned int size;	/* The aligned/padded/added on size  */
 	unsigned int align;	/* Alignment as calculated */
 	slab_flags_t flags;	/* Active flags on the slab */
-	const char *name;	/* Slab name for sysfs */
 	int refcount;		/* Use counter */
-	void (*ctor)(void *);	/* Called on object slot creation */
 	struct list_head list;	/* List of all slab caches on the system */
 };