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Subject[RFC] SLUB - define OO_ macro instead of hardcoded numbers
---

Please check -- wouldn't it be better to use such a macro?
At least it makes easy to understand the 65535 constant is
coming from if only I didn't miss anything :)

mm/slub.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)

Index: linux-2.6.git/mm/slub.c
===================================================================
--- linux-2.6.git.orig/mm/slub.c 2008-09-26 13:45:16.000000000 +0400
+++ linux-2.6.git/mm/slub.c 2008-10-22 20:10:59.000000000 +0400
@@ -153,6 +153,10 @@
#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
#endif

+#define OO_SHIFT 16
+#define OO_MASK ((1 << OO_SHIFT) - 1)
+#define OO_MAX OO_MASK
+
/* Internal SLUB flags */
#define __OBJECT_POISON 0x80000000 /* Poison object */
#define __SYSFS_ADD_DEFERRED 0x40000000 /* Not yet visible via sysfs */
@@ -290,7 +294,7 @@ static inline struct kmem_cache_order_ob
unsigned long size)
{
struct kmem_cache_order_objects x = {
- (order << 16) + (PAGE_SIZE << order) / size
+ (order << OO_SHIFT) + (PAGE_SIZE << order) / size
};

return x;
@@ -298,12 +302,12 @@ static inline struct kmem_cache_order_ob

static inline int oo_order(struct kmem_cache_order_objects x)
{
- return x.x >> 16;
+ return x.x >> OO_SHIFT;
}

static inline int oo_objects(struct kmem_cache_order_objects x)
{
- return x.x & ((1 << 16) - 1);
+ return x.x & OO_MASK;
}

#ifdef CONFIG_SLUB_DEBUG
@@ -764,8 +768,8 @@ static int on_freelist(struct kmem_cache
}

max_objects = (PAGE_SIZE << compound_order(page)) / s->size;
- if (max_objects > 65535)
- max_objects = 65535;
+ if (max_objects > OO_MAX)
+ max_objects = OO_MAX;

if (page->objects != max_objects) {
slab_err(s, page, "Wrong number of objects. Found %d but "
@@ -1819,8 +1823,8 @@ static inline int slab_order(int size, i
int rem;
int min_order = slub_min_order;

- if ((PAGE_SIZE << min_order) / size > 65535)
- return get_order(size * 65535) - 1;
+ if ((PAGE_SIZE << min_order) / size > OO_MAX)
+ return get_order(size * OO_MAX) - 1;

for (order = max(min_order,
fls(min_objects * size - 1) - PAGE_SHIFT);

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