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-rw-r--r--mm/zsmalloc.c126
1 files changed, 98 insertions, 28 deletions
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 0dec1fa5f656..6f3cfbf5e237 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -110,6 +110,8 @@
#define ZS_MAX_ZSPAGE_ORDER 2
#define ZS_MAX_PAGES_PER_ZSPAGE (_AC(1, UL) << ZS_MAX_ZSPAGE_ORDER)
+#define ZS_HANDLE_SIZE (sizeof(unsigned long))
+
/*
* Object location (<PFN>, <obj_idx>) is encoded as
* as single (unsigned long) handle value.
@@ -140,7 +142,8 @@
/* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */
#define ZS_MIN_ALLOC_SIZE \
MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS))
-#define ZS_MAX_ALLOC_SIZE PAGE_SIZE
+/* each chunk includes extra space to keep handle */
+#define ZS_MAX_ALLOC_SIZE (PAGE_SIZE + ZS_HANDLE_SIZE)
/*
* On systems with 4K page size, this gives 255 size classes! There is a
@@ -233,14 +236,24 @@ struct size_class {
* This must be power of 2 and less than or equal to ZS_ALIGN
*/
struct link_free {
- /* Handle of next free chunk (encodes <PFN, obj_idx>) */
- void *next;
+ union {
+ /*
+ * Position of next free chunk (encodes <PFN, obj_idx>)
+ * It's valid for non-allocated object
+ */
+ void *next;
+ /*
+ * Handle of allocated object.
+ */
+ unsigned long handle;
+ };
};
struct zs_pool {
char *name;
struct size_class **size_class;
+ struct kmem_cache *handle_cachep;
gfp_t flags; /* allocation flags used when growing pool */
atomic_long_t pages_allocated;
@@ -269,6 +282,34 @@ struct mapping_area {
enum zs_mapmode vm_mm; /* mapping mode */
};
+static int create_handle_cache(struct zs_pool *pool)
+{
+ pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE,
+ 0, 0, NULL);
+ return pool->handle_cachep ? 0 : 1;
+}
+
+static void destroy_handle_cache(struct zs_pool *pool)
+{
+ kmem_cache_destroy(pool->handle_cachep);
+}
+
+static unsigned long alloc_handle(struct zs_pool *pool)
+{
+ return (unsigned long)kmem_cache_alloc(pool->handle_cachep,
+ pool->flags & ~__GFP_HIGHMEM);
+}
+
+static void free_handle(struct zs_pool *pool, unsigned long handle)
+{
+ kmem_cache_free(pool->handle_cachep, (void *)handle);
+}
+
+static void record_obj(unsigned long handle, unsigned long obj)
+{
+ *(unsigned long *)handle = obj;
+}
+
/* zpool driver */
#ifdef CONFIG_ZPOOL
@@ -595,13 +636,18 @@ static void *obj_location_to_handle(struct page *page, unsigned long obj_idx)
* decoded obj_idx back to its original value since it was adjusted in
* obj_location_to_handle().
*/
-static void obj_handle_to_location(unsigned long handle, struct page **page,
+static void obj_to_location(unsigned long handle, struct page **page,
unsigned long *obj_idx)
{
*page = pfn_to_page(handle >> OBJ_INDEX_BITS);
*obj_idx = (handle & OBJ_INDEX_MASK) - 1;
}
+static unsigned long handle_to_obj(unsigned long handle)
+{
+ return *(unsigned long *)handle;
+}
+
static unsigned long obj_idx_to_offset(struct page *page,
unsigned long obj_idx, int class_size)
{
@@ -860,12 +906,16 @@ static void __zs_unmap_object(struct mapping_area *area,
{
int sizes[2];
void *addr;
- char *buf = area->vm_buf;
+ char *buf;
/* no write fastpath */
if (area->vm_mm == ZS_MM_RO)
goto out;
+ buf = area->vm_buf + ZS_HANDLE_SIZE;
+ size -= ZS_HANDLE_SIZE;
+ off += ZS_HANDLE_SIZE;
+
sizes[0] = PAGE_SIZE - off;
sizes[1] = size - sizes[0];
@@ -1153,13 +1203,14 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
enum zs_mapmode mm)
{
struct page *page;
- unsigned long obj_idx, off;
+ unsigned long obj, obj_idx, off;
unsigned int class_idx;
enum fullness_group fg;
struct size_class *class;
struct mapping_area *area;
struct page *pages[2];
+ void *ret;
BUG_ON(!handle);
@@ -1170,7 +1221,8 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
*/
BUG_ON(in_interrupt());
- obj_handle_to_location(handle, &page, &obj_idx);
+ obj = handle_to_obj(handle);
+ obj_to_location(obj, &page, &obj_idx);
get_zspage_mapping(get_first_page(page), &class_idx, &fg);
class = pool->size_class[class_idx];
off = obj_idx_to_offset(page, obj_idx, class->size);
@@ -1180,7 +1232,8 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
if (off + class->size <= PAGE_SIZE) {
/* this object is contained entirely within a page */
area->vm_addr = kmap_atomic(page);
- return area->vm_addr + off;
+ ret = area->vm_addr + off;
+ goto out;
}
/* this object spans two pages */
@@ -1188,14 +1241,16 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
pages[1] = get_next_page(page);
BUG_ON(!pages[1]);
- return __zs_map_object(area, pages, off, class->size);
+ ret = __zs_map_object(area, pages, off, class->size);
+out:
+ return ret + ZS_HANDLE_SIZE;
}
EXPORT_SYMBOL_GPL(zs_map_object);
void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
{
struct page *page;
- unsigned long obj_idx, off;
+ unsigned long obj, obj_idx, off;
unsigned int class_idx;
enum fullness_group fg;
@@ -1204,7 +1259,8 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
BUG_ON(!handle);
- obj_handle_to_location(handle, &page, &obj_idx);
+ obj = handle_to_obj(handle);
+ obj_to_location(obj, &page, &obj_idx);
get_zspage_mapping(get_first_page(page), &class_idx, &fg);
class = pool->size_class[class_idx];
off = obj_idx_to_offset(page, obj_idx, class->size);
@@ -1236,7 +1292,7 @@ EXPORT_SYMBOL_GPL(zs_unmap_object);
*/
unsigned long zs_malloc(struct zs_pool *pool, size_t size)
{
- unsigned long obj;
+ unsigned long handle, obj;
struct link_free *link;
struct size_class *class;
void *vaddr;
@@ -1244,9 +1300,15 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size)
struct page *first_page, *m_page;
unsigned long m_objidx, m_offset;
- if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE))
+ if (unlikely(!size || (size + ZS_HANDLE_SIZE) > ZS_MAX_ALLOC_SIZE))
+ return 0;
+
+ handle = alloc_handle(pool);
+ if (!handle)
return 0;
+ /* extra space in chunk to keep the handle */
+ size += ZS_HANDLE_SIZE;
class = pool->size_class[get_size_class_index(size)];
spin_lock(&class->lock);
@@ -1255,8 +1317,10 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size)
if (!first_page) {
spin_unlock(&class->lock);
first_page = alloc_zspage(class, pool->flags);
- if (unlikely(!first_page))
+ if (unlikely(!first_page)) {
+ free_handle(pool, handle);
return 0;
+ }
set_zspage_mapping(first_page, class->index, ZS_EMPTY);
atomic_long_add(class->pages_per_zspage,
@@ -1268,40 +1332,45 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size)
}
obj = (unsigned long)first_page->freelist;
- obj_handle_to_location(obj, &m_page, &m_objidx);
+ obj_to_location(obj, &m_page, &m_objidx);
m_offset = obj_idx_to_offset(m_page, m_objidx, class->size);
vaddr = kmap_atomic(m_page);
link = (struct link_free *)vaddr + m_offset / sizeof(*link);
first_page->freelist = link->next;
- memset(link, POISON_INUSE, sizeof(*link));
+
+ /* record handle in the header of allocated chunk */
+ link->handle = handle;
kunmap_atomic(vaddr);
first_page->inuse++;
zs_stat_inc(class, OBJ_USED, 1);
/* Now move the zspage to another fullness group, if required */
fix_fullness_group(pool, first_page);
+ record_obj(handle, obj);
spin_unlock(&class->lock);
- return obj;
+ return handle;
}
EXPORT_SYMBOL_GPL(zs_malloc);
-void zs_free(struct zs_pool *pool, unsigned long obj)
+void zs_free(struct zs_pool *pool, unsigned long handle)
{
struct link_free *link;
struct page *first_page, *f_page;
- unsigned long f_objidx, f_offset;
+ unsigned long obj, f_objidx, f_offset;
void *vaddr;
int class_idx;
struct size_class *class;
enum fullness_group fullness;
- if (unlikely(!obj))
+ if (unlikely(!handle))
return;
- obj_handle_to_location(obj, &f_page, &f_objidx);
+ obj = handle_to_obj(handle);
+ free_handle(pool, handle);
+ obj_to_location(obj, &f_page, &f_objidx);
first_page = get_first_page(f_page);
get_zspage_mapping(first_page, &class_idx, &fullness);
@@ -1355,20 +1424,20 @@ struct zs_pool *zs_create_pool(char *name, gfp_t flags)
if (!pool)
return NULL;
- pool->name = kstrdup(name, GFP_KERNEL);
- if (!pool->name) {
- kfree(pool);
- return NULL;
- }
-
pool->size_class = kcalloc(zs_size_classes, sizeof(struct size_class *),
GFP_KERNEL);
if (!pool->size_class) {
- kfree(pool->name);
kfree(pool);
return NULL;
}
+ pool->name = kstrdup(name, GFP_KERNEL);
+ if (!pool->name)
+ goto err;
+
+ if (create_handle_cache(pool))
+ goto err;
+
/*
* Iterate reversly, because, size of size_class that we want to use
* for merging should be larger or equal to current size.
@@ -1450,6 +1519,7 @@ void zs_destroy_pool(struct zs_pool *pool)
kfree(class);
}
+ destroy_handle_cache(pool);
kfree(pool->size_class);
kfree(pool->name);
kfree(pool);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 16:31:34 +0000