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authorMahendran Ganesh <opensource.ganesh@gmail.com>2014-12-13 03:57:01 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-13 23:42:50 +0300
commit40f9fb8cffc6a20ae269e3b43dfba7a4f65d7f50 (patch)
tree734307fb40afba740ff4b0a6b34a0807fba4cc64
parentaf4ee5e977acb150371c28bd85cb7e34cac48b13 (diff)
downloadlinux-40f9fb8cffc6a20ae269e3b43dfba7a4f65d7f50.tar.xz
mm/zsmalloc: support allocating obj with size of ZS_MAX_ALLOC_SIZE
I sent a patch [1] for unnecessary check in zsmalloc. And Minchan Kim found zsmalloc even does not support allocating an obj with the size of ZS_MAX_ALLOC_SIZE in some situations. For example: In system with 64KB PAGE_SIZE and 32 bit of physical addr. Then: ZS_MIN_ALLOC_SIZE is 32 bytes which is calculated by: MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS)) ZS_MAX_ALLOC_SIZE is 64KB(in current code, is PAGE_SIZE) ZS_SIZE_CLASS_DELTA is 256 bytes So, ZS_SIZE_CLASSES = (ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) / ZS_SIZE_CLASS_DELTA + 1 = 256 In zs_create_pool(), the max size obj which can be allocated will be: ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA = 32 + 255*256 = 65312 We can see that 65312 < 65536 (ZS_MAX_ALLOC_SIZE). So we can NOT allocate objs with size ZS_MAX_ALLOC_SIZE(65536) which we promise upper users we can do. [1] http://lkml.iu.edu/hypermail/linux/kernel/1411.2/03835.html [2] http://lkml.iu.edu/hypermail/linux/kernel/1411.2/04534.html This patch fixes this issue by dynamiclly calculating zs_size_classes when module is loaded, allocates buffer with size ZS_MAX_ALLOC_SIZE. Then the max obj(size is ZS_MAX_ALLOC_SIZE) can be stored in it. [akpm@linux-foundation.org: restore ZS_SIZE_CLASSES to fix bisectability] Signed-off-by: Mahendran Ganesh <opensource.ganesh@gmail.com> Suggested-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/zsmalloc.c38
1 files changed, 32 insertions, 6 deletions
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 83ecdb675c40..61e180931ca8 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -171,6 +171,11 @@ enum fullness_group {
};
/*
+ * number of size_classes
+ */
+static int zs_size_classes;
+
+/*
* We assign a page to ZS_ALMOST_EMPTY fullness group when:
* n <= N / f, where
* n = number of allocated objects
@@ -214,7 +219,7 @@ struct link_free {
};
struct zs_pool {
- struct size_class *size_class[ZS_SIZE_CLASSES];
+ struct size_class **size_class;
gfp_t flags; /* allocation flags used when growing pool */
atomic_long_t pages_allocated;
@@ -785,7 +790,7 @@ static inline int __zs_cpu_up(struct mapping_area *area)
*/
if (area->vm_buf)
return 0;
- area->vm_buf = (char *)__get_free_page(GFP_KERNEL);
+ area->vm_buf = kmalloc(ZS_MAX_ALLOC_SIZE, GFP_KERNEL);
if (!area->vm_buf)
return -ENOMEM;
return 0;
@@ -793,8 +798,7 @@ static inline int __zs_cpu_up(struct mapping_area *area)
static inline void __zs_cpu_down(struct mapping_area *area)
{
- if (area->vm_buf)
- free_page((unsigned long)area->vm_buf);
+ kfree(area->vm_buf);
area->vm_buf = NULL;
}
@@ -912,6 +916,17 @@ static int zs_register_cpu_notifier(void)
return notifier_to_errno(ret);
}
+static void init_zs_size_classes(void)
+{
+ int nr;
+
+ nr = (ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) / ZS_SIZE_CLASS_DELTA + 1;
+ if ((ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) % ZS_SIZE_CLASS_DELTA)
+ nr += 1;
+
+ zs_size_classes = nr;
+}
+
static void __exit zs_exit(void)
{
#ifdef CONFIG_ZPOOL
@@ -929,6 +944,8 @@ static int __init zs_init(void)
return ret;
}
+ init_zs_size_classes();
+
#ifdef CONFIG_ZPOOL
zpool_register_driver(&zs_zpool_driver);
#endif
@@ -972,11 +989,18 @@ struct zs_pool *zs_create_pool(gfp_t flags)
if (!pool)
return NULL;
+ pool->size_class = kcalloc(zs_size_classes, sizeof(struct size_class *),
+ GFP_KERNEL);
+ if (!pool->size_class) {
+ kfree(pool);
+ return NULL;
+ }
+
/*
* Iterate reversly, because, size of size_class that we want to use
* for merging should be larger or equal to current size.
*/
- for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
+ for (i = zs_size_classes - 1; i >= 0; i--) {
int size;
int pages_per_zspage;
struct size_class *class;
@@ -1029,7 +1053,7 @@ void zs_destroy_pool(struct zs_pool *pool)
{
int i;
- for (i = 0; i < ZS_SIZE_CLASSES; i++) {
+ for (i = 0; i < zs_size_classes; i++) {
int fg;
struct size_class *class = pool->size_class[i];
@@ -1047,6 +1071,8 @@ void zs_destroy_pool(struct zs_pool *pool)
}
kfree(class);
}
+
+ kfree(pool->size_class);
kfree(pool);
}
EXPORT_SYMBOL_GPL(zs_destroy_pool);