[PATCH v5 06/12] zsmalloc: use accessor

Minchan Kim
2016-05-09T02:21:54Z

Upcoming patch will change how to encode zspage meta so for easy review,
this patch wraps code to access metadata as accessor.

Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
mm/zsmalloc.c | 82 +++++++++++++++++++++++++++++++++++++++++++----------------
1 file changed, 60 insertions(+), 22 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 718dde7fd028..086fd65311f7 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -266,10 +266,14 @@ struct zs_pool {
* A zspage's class index and fullness group
* are encoded in its (first)page->mapping
*/
-#define CLASS_IDX_BITS 28
#define FULLNESS_BITS 4
-#define CLASS_IDX_MASK ((1 << CLASS_IDX_BITS) - 1)
-#define FULLNESS_MASK ((1 << FULLNESS_BITS) - 1)
+#define CLASS_BITS 28
+
+#define FULLNESS_SHIFT 0
+#define CLASS_SHIFT (FULLNESS_SHIFT + FULLNESS_BITS)
+
+#define FULLNESS_MASK ((1UL << FULLNESS_BITS) - 1)
+#define CLASS_MASK ((1UL << CLASS_BITS) - 1)

struct mapping_area {
#ifdef CONFIG_PGTABLE_MAPPING
@@ -416,6 +420,41 @@ static int is_last_page(struct page *page)
return PagePrivate2(page);
}

+static inline int get_zspage_inuse(struct page *first_page)
+{
+ return first_page->inuse;
+}
+
+static inline void set_zspage_inuse(struct page *first_page, int val)
+{
+ first_page->inuse = val;
+}
+
+static inline void mod_zspage_inuse(struct page *first_page, int val)
+{
+ first_page->inuse += val;
+}
+
+static inline int get_first_obj_offset(struct page *page)
+{
+ return page->index;
+}
+
+static inline void set_first_obj_offset(struct page *page, int offset)
+{
+ page->index = offset;
+}
+
+static inline unsigned long get_freeobj(struct page *first_page)
+{
+ return (unsigned long)first_page->freelist;
+}
+
+static inline void set_freeobj(struct page *first_page, unsigned long obj)
+{
+ first_page->freelist = (void *)obj;
+}
+
static void get_zspage_mapping(struct page *first_page,
unsigned int *class_idx,
enum fullness_group *fullness)
@@ -424,8 +463,8 @@ static void get_zspage_mapping(struct page *first_page,
VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);

m = (unsigned long)first_page->mapping;
- *fullness = m & FULLNESS_MASK;
- *class_idx = (m >> FULLNESS_BITS) & CLASS_IDX_MASK;
+ *fullness = (m >> FULLNESS_SHIFT) & FULLNESS_MASK;
+ *class_idx = (m >> CLASS_SHIFT) & CLASS_MASK;
}

static void set_zspage_mapping(struct page *first_page,
@@ -435,8 +474,7 @@ static void set_zspage_mapping(struct page *first_page,
unsigned long m;
VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);

- m = ((class_idx & CLASS_IDX_MASK) << FULLNESS_BITS) |
- (fullness & FULLNESS_MASK);
+ m = (class_idx << CLASS_SHIFT) | (fullness << FULLNESS_SHIFT);
first_page->mapping = (struct address_space *)m;
}

@@ -634,7 +672,7 @@ static enum fullness_group get_fullness_group(struct size_class *class,

VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);

- inuse = first_page->inuse;
+ inuse = get_zspage_inuse(first_page);
objs_per_zspage = class->objs_per_zspage;

if (inuse == 0)
@@ -680,7 +718,7 @@ static void insert_zspage(struct size_class *class,
* empty/full. Put pages with higher ->inuse first.
*/
list_add_tail(&first_page->lru, &(*head)->lru);
- if (first_page->inuse >= (*head)->inuse)
+ if (get_zspage_inuse(first_page) >= get_zspage_inuse(*head))
*head = first_page;
}

@@ -860,7 +898,7 @@ static unsigned long obj_idx_to_offset(struct page *page,
unsigned long off = 0;

if (!is_first_page(page))
- off = page->index;
+ off = get_first_obj_offset(page);

return off + obj_idx * class_size;
}
@@ -895,7 +933,7 @@ static void free_zspage(struct page *first_page)
struct page *nextp, *tmp, *head_extra;

VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
- VM_BUG_ON_PAGE(first_page->inuse, first_page);
+ VM_BUG_ON_PAGE(get_zspage_inuse(first_page), first_page);

head_extra = (struct page *)page_private(first_page);

@@ -936,7 +974,7 @@ static void init_zspage(struct size_class *class, struct page *first_page)
* head of corresponding zspage's freelist.
*/
if (page != first_page)
- page->index = off;
+ set_first_obj_offset(page, off);

vaddr = kmap_atomic(page);
link = (struct link_free *)vaddr + off / sizeof(*link);
@@ -991,7 +1029,7 @@ static struct page *alloc_zspage(struct size_class *class, gfp_t flags)
SetPagePrivate(page);
set_page_private(page, 0);
first_page = page;
- first_page->inuse = 0;
+ set_zspage_inuse(first_page, 0);
}
if (i == 1)
set_page_private(first_page, (unsigned long)page);
@@ -1006,7 +1044,7 @@ static struct page *alloc_zspage(struct size_class *class, gfp_t flags)

init_zspage(class, first_page);

- first_page->freelist = location_to_obj(first_page, 0);
+ set_freeobj(first_page, (unsigned long)location_to_obj(first_page, 0));
error = 0; /* Success */

cleanup:
@@ -1238,7 +1276,7 @@ static bool zspage_full(struct size_class *class, struct page *first_page)
{
VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);

- return first_page->inuse == class->objs_per_zspage;
+ return get_zspage_inuse(first_page) == class->objs_per_zspage;
}

unsigned long zs_get_total_pages(struct zs_pool *pool)
@@ -1357,13 +1395,13 @@ static unsigned long obj_malloc(struct size_class *class,
void *vaddr;

handle |= OBJ_ALLOCATED_TAG;
- obj = (unsigned long)first_page->freelist;
+ obj = get_freeobj(first_page);
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;
+ set_freeobj(first_page, (unsigned long)link->next);
if (!class->huge)
/* record handle in the header of allocated chunk */
link->handle = handle;
@@ -1371,7 +1409,7 @@ static unsigned long obj_malloc(struct size_class *class,
/* record handle in first_page->private */
set_page_private(first_page, handle);
kunmap_atomic(vaddr);
- first_page->inuse++;
+ mod_zspage_inuse(first_page, 1);
zs_stat_inc(class, OBJ_USED, 1);

return obj;
@@ -1451,12 +1489,12 @@ static void obj_free(struct size_class *class, unsigned long obj)

/* Insert this object in containing zspage's freelist */
link = (struct link_free *)(vaddr + f_offset);
- link->next = first_page->freelist;
+ link->next = (void *)get_freeobj(first_page);
if (class->huge)
set_page_private(first_page, 0);
kunmap_atomic(vaddr);
- first_page->freelist = (void *)obj;
- first_page->inuse--;
+ set_freeobj(first_page, obj);
+ mod_zspage_inuse(first_page, -1);
zs_stat_dec(class, OBJ_USED, 1);
}

@@ -1572,7 +1610,7 @@ static unsigned long find_alloced_obj(struct size_class *class,
void *addr = kmap_atomic(page);

if (!is_first_page(page))
- offset = page->index;
+ offset = get_first_obj_offset(page);
offset += class->size * index;

while (offset < PAGE_SIZE) {
--
1.9.1