slob: Rework #ifdeffery in slab.h
Make the SLOB specific stuff harmonize more with the way the other allocators
do it. Create the typical kmalloc constants for that purpose. SLOB does not
support it but the constants help us avoid #ifdefs.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 0c62175..9690c14 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -169,11 +169,7 @@
struct list_head list; /* List of all slab caches on the system */
};
-#define KMALLOC_MAX_SIZE (1UL << 30)
-
-#include <linux/slob_def.h>
-
-#else /* CONFIG_SLOB */
+#endif /* CONFIG_SLOB */
/*
* Kmalloc array related definitions
@@ -195,7 +191,9 @@
#ifndef KMALLOC_SHIFT_LOW
#define KMALLOC_SHIFT_LOW 5
#endif
-#else
+#endif
+
+#ifdef CONFIG_SLUB
/*
* SLUB allocates up to order 2 pages directly and otherwise
* passes the request to the page allocator.
@@ -207,6 +205,19 @@
#endif
#endif
+#ifdef CONFIG_SLOB
+/*
+ * SLOB passes all page size and larger requests to the page allocator.
+ * No kmalloc array is necessary since objects of different sizes can
+ * be allocated from the same page.
+ */
+#define KMALLOC_SHIFT_MAX 30
+#define KMALLOC_SHIFT_HIGH PAGE_SHIFT
+#ifndef KMALLOC_SHIFT_LOW
+#define KMALLOC_SHIFT_LOW 3
+#endif
+#endif
+
/* Maximum allocatable size */
#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX)
/* Maximum size for which we actually use a slab cache */
@@ -221,6 +232,7 @@
#define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
#endif
+#ifndef CONFIG_SLOB
extern struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
#ifdef CONFIG_ZONE_DMA
extern struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1];
@@ -275,13 +287,18 @@
/* Will never be reached. Needed because the compiler may complain */
return -1;
}
+#endif /* !CONFIG_SLOB */
#ifdef CONFIG_SLAB
#include <linux/slab_def.h>
-#elif defined(CONFIG_SLUB)
+#endif
+
+#ifdef CONFIG_SLUB
#include <linux/slub_def.h>
-#else
-#error "Unknown slab allocator"
+#endif
+
+#ifdef CONFIG_SLOB
+#include <linux/slob_def.h>
#endif
/*
@@ -291,6 +308,7 @@
*/
static __always_inline int kmalloc_size(int n)
{
+#ifndef CONFIG_SLOB
if (n > 2)
return 1 << n;
@@ -299,10 +317,9 @@
if (n == 2 && KMALLOC_MIN_SIZE <= 64)
return 192;
-
+#endif
return 0;
}
-#endif /* !CONFIG_SLOB */
/*
* Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.