[PATCH] change gen_pool allocator to not touch managed memory
Modify the gen_pool allocator (lib/genalloc.c) to utilize a bitmap scheme
instead of the buddy scheme. The purpose of this change is to eliminate
the touching of the actual memory being allocated.
Since the change modifies the interface, a change to the uncached allocator
(arch/ia64/kernel/uncached.c) is also required.
Both Andrey Volkov and Jes Sorenson have expressed a desire that the
gen_pool allocator not write to the memory being managed. See the
following:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113518602713125&w=2
http://marc.theaimsgroup.com/?l=linux-kernel&m=113533568827916&w=2
Signed-off-by: Dean Nelson <dcn@sgi.com>
Cc: Andrey Volkov <avolkov@varma-el.com>
Acked-by: Jes Sorensen <jes@trained-monkey.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h
index 7fd0576..690c428 100644
--- a/include/linux/genalloc.h
+++ b/include/linux/genalloc.h
@@ -4,37 +4,32 @@
* Uses for this includes on-device special memory, uncached memory
* etc.
*
- * This code is based on the buddy allocator found in the sym53c8xx_2
- * driver, adapted for general purpose use.
- *
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
-#include <linux/spinlock.h>
-
-#define ALLOC_MIN_SHIFT 5 /* 32 bytes minimum */
-/*
- * Link between free memory chunks of a given size.
- */
-struct gen_pool_link {
- struct gen_pool_link *next;
-};
/*
- * Memory pool descriptor.
+ * General purpose special memory pool descriptor.
*/
struct gen_pool {
- spinlock_t lock;
- unsigned long (*get_new_chunk)(struct gen_pool *);
- struct gen_pool *next;
- struct gen_pool_link *h;
- unsigned long private;
- int max_chunk_shift;
+ rwlock_t lock;
+ struct list_head chunks; /* list of chunks in this pool */
+ int min_alloc_order; /* minimum allocation order */
};
-unsigned long gen_pool_alloc(struct gen_pool *poolp, int size);
-void gen_pool_free(struct gen_pool *mp, unsigned long ptr, int size);
-struct gen_pool *gen_pool_create(int nr_chunks, int max_chunk_shift,
- unsigned long (*fp)(struct gen_pool *),
- unsigned long data);
+/*
+ * General purpose special memory pool chunk descriptor.
+ */
+struct gen_pool_chunk {
+ spinlock_t lock;
+ struct list_head next_chunk; /* next chunk in pool */
+ unsigned long start_addr; /* starting address of memory chunk */
+ unsigned long end_addr; /* ending address of memory chunk */
+ unsigned long bits[0]; /* bitmap for allocating memory chunk */
+};
+
+extern struct gen_pool *gen_pool_create(int, int);
+extern int gen_pool_add(struct gen_pool *, unsigned long, size_t, int);
+extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
+extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);