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slab, slub, slob: convert slab_flags_t to 32-bit
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struct kmem_cache::flags is "unsigned long" which is unnecessary on
64-bit as no flags are defined in the higher bits.

Switch the field to 32-bit and save some space on x86_64 until such
flags appear:

	add/remove: 0/0 grow/shrink: 0/107 up/down: 0/-657 (-657)
	function                                     old     new   delta
	sysfs_slab_add                               720     719      -1
				...
	check_object                                 699     676     -23

[akpm@linux-foundation.org: fix printk warning]
Link: http://lkml.kernel.org/r/20171021100635.GA8287@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Alexey Dobriyan authored and torvalds committed Nov 16, 2017
1 parent d50112e commit 4fd0b46
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Showing 4 changed files with 28 additions and 28 deletions.
44 changes: 22 additions & 22 deletions include/linux/slab.h
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Original file line number Diff line number Diff line change
Expand Up @@ -22,19 +22,19 @@
* The ones marked DEBUG are only valid if CONFIG_DEBUG_SLAB is set.
*/
/* DEBUG: Perform (expensive) checks on alloc/free */
#define SLAB_CONSISTENCY_CHECKS ((slab_flags_t __force)0x00000100UL)
#define SLAB_CONSISTENCY_CHECKS ((slab_flags_t __force)0x00000100U)
/* DEBUG: Red zone objs in a cache */
#define SLAB_RED_ZONE ((slab_flags_t __force)0x00000400UL)
#define SLAB_RED_ZONE ((slab_flags_t __force)0x00000400U)
/* DEBUG: Poison objects */
#define SLAB_POISON ((slab_flags_t __force)0x00000800UL)
#define SLAB_POISON ((slab_flags_t __force)0x00000800U)
/* Align objs on cache lines */
#define SLAB_HWCACHE_ALIGN ((slab_flags_t __force)0x00002000UL)
#define SLAB_HWCACHE_ALIGN ((slab_flags_t __force)0x00002000U)
/* Use GFP_DMA memory */
#define SLAB_CACHE_DMA ((slab_flags_t __force)0x00004000UL)
#define SLAB_CACHE_DMA ((slab_flags_t __force)0x00004000U)
/* DEBUG: Store the last owner for bug hunting */
#define SLAB_STORE_USER ((slab_flags_t __force)0x00010000UL)
#define SLAB_STORE_USER ((slab_flags_t __force)0x00010000U)
/* Panic if kmem_cache_create() fails */
#define SLAB_PANIC ((slab_flags_t __force)0x00040000UL)
#define SLAB_PANIC ((slab_flags_t __force)0x00040000U)
/*
* SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
*
Expand Down Expand Up @@ -73,50 +73,50 @@
* Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
*/
/* Defer freeing slabs to RCU */
#define SLAB_TYPESAFE_BY_RCU ((slab_flags_t __force)0x00080000UL)
#define SLAB_TYPESAFE_BY_RCU ((slab_flags_t __force)0x00080000U)
/* Spread some memory over cpuset */
#define SLAB_MEM_SPREAD ((slab_flags_t __force)0x00100000UL)
#define SLAB_MEM_SPREAD ((slab_flags_t __force)0x00100000U)
/* Trace allocations and frees */
#define SLAB_TRACE ((slab_flags_t __force)0x00200000UL)
#define SLAB_TRACE ((slab_flags_t __force)0x00200000U)

/* Flag to prevent checks on free */
#ifdef CONFIG_DEBUG_OBJECTS
# define SLAB_DEBUG_OBJECTS ((slab_flags_t __force)0x00400000UL)
# define SLAB_DEBUG_OBJECTS ((slab_flags_t __force)0x00400000U)
#else
# define SLAB_DEBUG_OBJECTS ((slab_flags_t __force)0x00000000UL)
# define SLAB_DEBUG_OBJECTS 0
#endif

/* Avoid kmemleak tracing */
#define SLAB_NOLEAKTRACE ((slab_flags_t __force)0x00800000UL)
#define SLAB_NOLEAKTRACE ((slab_flags_t __force)0x00800000U)

/* Don't track use of uninitialized memory */
#ifdef CONFIG_KMEMCHECK
# define SLAB_NOTRACK ((slab_flags_t __force)0x01000000UL)
# define SLAB_NOTRACK ((slab_flags_t __force)0x01000000U)
#else
# define SLAB_NOTRACK ((slab_flags_t __force)0x00000000UL)
# define SLAB_NOTRACK 0
#endif
/* Fault injection mark */
#ifdef CONFIG_FAILSLAB
# define SLAB_FAILSLAB ((slab_flags_t __force)0x02000000UL)
# define SLAB_FAILSLAB ((slab_flags_t __force)0x02000000U)
#else
# define SLAB_FAILSLAB ((slab_flags_t __force)0x00000000UL)
# define SLAB_FAILSLAB 0
#endif
/* Account to memcg */
#if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
# define SLAB_ACCOUNT ((slab_flags_t __force)0x04000000UL)
# define SLAB_ACCOUNT ((slab_flags_t __force)0x04000000U)
#else
# define SLAB_ACCOUNT ((slab_flags_t __force)0x00000000UL)
# define SLAB_ACCOUNT 0
#endif

#ifdef CONFIG_KASAN
#define SLAB_KASAN ((slab_flags_t __force)0x08000000UL)
#define SLAB_KASAN ((slab_flags_t __force)0x08000000U)
#else
#define SLAB_KASAN ((slab_flags_t __force)0x00000000UL)
#define SLAB_KASAN 0
#endif

/* The following flags affect the page allocator grouping pages by mobility */
/* Objects are reclaimable */
#define SLAB_RECLAIM_ACCOUNT ((slab_flags_t __force)0x00020000UL)
#define SLAB_RECLAIM_ACCOUNT ((slab_flags_t __force)0x00020000U)
#define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
/*
* ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
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2 changes: 1 addition & 1 deletion include/linux/types.h
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Original file line number Diff line number Diff line change
Expand Up @@ -156,7 +156,7 @@ typedef u32 dma_addr_t;
#endif

typedef unsigned __bitwise gfp_t;
typedef unsigned long __bitwise slab_flags_t;
typedef unsigned __bitwise slab_flags_t;
typedef unsigned __bitwise fmode_t;

#ifdef CONFIG_PHYS_ADDR_T_64BIT
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4 changes: 2 additions & 2 deletions mm/slab.c
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Original file line number Diff line number Diff line change
Expand Up @@ -252,8 +252,8 @@ static void kmem_cache_node_init(struct kmem_cache_node *parent)
MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
} while (0)

#define CFLGS_OBJFREELIST_SLAB ((slab_flags_t __force)0x40000000UL)
#define CFLGS_OFF_SLAB ((slab_flags_t __force)0x80000000UL)
#define CFLGS_OBJFREELIST_SLAB ((slab_flags_t __force)0x40000000U)
#define CFLGS_OFF_SLAB ((slab_flags_t __force)0x80000000U)
#define OBJFREELIST_SLAB(x) ((x)->flags & CFLGS_OBJFREELIST_SLAB)
#define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)

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6 changes: 3 additions & 3 deletions mm/slub.c
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Original file line number Diff line number Diff line change
Expand Up @@ -194,9 +194,9 @@ static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)

/* Internal SLUB flags */
/* Poison object */
#define __OBJECT_POISON ((slab_flags_t __force)0x80000000UL)
#define __OBJECT_POISON ((slab_flags_t __force)0x80000000U)
/* Use cmpxchg_double */
#define __CMPXCHG_DOUBLE ((slab_flags_t __force)0x40000000UL)
#define __CMPXCHG_DOUBLE ((slab_flags_t __force)0x40000000U)

/*
* Tracking user of a slab.
Expand Down Expand Up @@ -3657,7 +3657,7 @@ static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
if (flags & SLAB_PANIC)
panic("Cannot create slab %s size=%lu realsize=%u order=%u offset=%u flags=%lx\n",
s->name, (unsigned long)s->size, s->size,
oo_order(s->oo), s->offset, flags);
oo_order(s->oo), s->offset, (unsigned long)flags);
return -EINVAL;
}

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