[RFC] SL[AUO]B common code 1/9] [slob] define page struct fields used in mm_types.h

Christoph Lameter
2012-05-14T20:36:24Z

[-- Attachment #1: slob_use_page_struct --]
[-- Type: text/plain, Size: 9015 bytes --]

Define the fields used by slob in mm_types.h and use struct page instead
of struct slob_page in slob. This cleans up a lot of typecasts in slob.c and
makes readers aware of slob's use of page struct fields.

[Also cleans up some bitrot in slob.c. The page struct field layout
in slob.c is an old layout and does not match the one in mm_types.h]

Signed-off-by: Christoph Lameter <cl@linux.com>

---
include/linux/mm_types.h | 5 +-
mm/slob.c | 105 ++++++++++++++++++-----------------------------
2 files changed, 45 insertions(+), 65 deletions(-)

Index: linux-2.6/mm/slob.c
===================================================================
--- linux-2.6.orig/mm/slob.c 2012-04-11 07:07:16.672129272 -0500
+++ linux-2.6/mm/slob.c 2012-04-11 07:12:34.344122598 -0500
@@ -92,33 +92,12 @@ struct slob_block {
typedef struct slob_block slob_t;

/*
- * We use struct page fields to manage some slob allocation aspects,
- * however to avoid the horrible mess in include/linux/mm_types.h, we'll
- * just define our own struct page type variant here.
- */
-struct slob_page {
- union {
- struct {
- unsigned long flags; /* mandatory */
- atomic_t _count; /* mandatory */
- slobidx_t units; /* free units left in page */
- unsigned long pad[2];
- slob_t *free; /* first free slob_t in page */
- struct list_head list; /* linked list of free pages */
- };
- struct page page;
- };
-};
-static inline void struct_slob_page_wrong_size(void)
-{ BUILD_BUG_ON(sizeof(struct slob_page) != sizeof(struct page)); }
-
-/*
* free_slob_page: call before a slob_page is returned to the page allocator.
*/
-static inline void free_slob_page(struct slob_page *sp)
+static inline void free_slob_page(struct page *sp)
{
- reset_page_mapcount(&sp->page);
- sp->page.mapping = NULL;
+ reset_page_mapcount(sp);
+ sp->mapping = NULL;
}

/*
@@ -133,44 +112,44 @@ static LIST_HEAD(free_slob_large);
/*
* is_slob_page: True for all slob pages (false for bigblock pages)
*/
-static inline int is_slob_page(struct slob_page *sp)
+static inline int is_slob_page(struct page *sp)
{
- return PageSlab((struct page *)sp);
+ return PageSlab(sp);
}

-static inline void set_slob_page(struct slob_page *sp)
+static inline void set_slob_page(struct page *sp)
{
- __SetPageSlab((struct page *)sp);
+ __SetPageSlab(sp);
}

-static inline void clear_slob_page(struct slob_page *sp)
+static inline void clear_slob_page(struct page *sp)
{
- __ClearPageSlab((struct page *)sp);
+ __ClearPageSlab(sp);
}

-static inline struct slob_page *slob_page(const void *addr)
+static inline struct page *slob_page(const void *addr)
{
- return (struct slob_page *)virt_to_page(addr);
+ return virt_to_page(addr);
}

/*
* slob_page_free: true for pages on free_slob_pages list.
*/
-static inline int slob_page_free(struct slob_page *sp)
+static inline int slob_page_free(struct page *sp)
{
- return PageSlobFree((struct page *)sp);
+ return PageSlobFree(sp);
}

-static void set_slob_page_free(struct slob_page *sp, struct list_head *list)
+static void set_slob_page_free(struct page *sp, struct list_head *list)
{
- list_add(&sp->list, list);
- __SetPageSlobFree((struct page *)sp);
+ list_add(&sp->lru, list);
+ __SetPageSlobFree(sp);
}

-static inline void clear_slob_page_free(struct slob_page *sp)
+static inline void clear_slob_page_free(struct page *sp)
{
- list_del(&sp->list);
- __ClearPageSlobFree((struct page *)sp);
+ list_del(&sp->lru);
+ __ClearPageSlobFree(sp);
}

#define SLOB_UNIT sizeof(slob_t)
@@ -267,12 +246,12 @@ static void slob_free_pages(void *b, int
/*
* Allocate a slob block within a given slob_page sp.
*/
-static void *slob_page_alloc(struct slob_page *sp, size_t size, int align)
+static void *slob_page_alloc(struct page *sp, size_t size, int align)
{
slob_t *prev, *cur, *aligned = NULL;
int delta = 0, units = SLOB_UNITS(size);

- for (prev = NULL, cur = sp->free; ; prev = cur, cur = slob_next(cur)) {
+ for (prev = NULL, cur = sp->freelist; ; prev = cur, cur = slob_next(cur)) {
slobidx_t avail = slob_units(cur);

if (align) {
@@ -296,12 +275,12 @@ static void *slob_page_alloc(struct slob
if (prev)
set_slob(prev, slob_units(prev), next);
else
- sp->free = next;
+ sp->freelist = next;
} else { /* fragment */
if (prev)
set_slob(prev, slob_units(prev), cur + units);
else
- sp->free = cur + units;
+ sp->freelist = cur + units;
set_slob(cur + units, avail - units, next);
}

@@ -320,7 +299,7 @@ static void *slob_page_alloc(struct slob
*/
static void *slob_alloc(size_t size, gfp_t gfp, int align, int node)
{
- struct slob_page *sp;
+ struct page *sp;
struct list_head *prev;
struct list_head *slob_list;
slob_t *b = NULL;
@@ -335,13 +314,13 @@ static void *slob_alloc(size_t size, gfp

spin_lock_irqsave(&slob_lock, flags);
/* Iterate through each partially free page, try to find room */
- list_for_each_entry(sp, slob_list, list) {
+ list_for_each_entry(sp, slob_list, lru) {
#ifdef CONFIG_NUMA
/*
* If there's a node specification, search for a partial
* page with a matching node id in the freelist.
*/
- if (node != -1 && page_to_nid(&sp->page) != node)
+ if (node != -1 && page_to_nid(sp) != node)
continue;
#endif
/* Enough room on this page? */
@@ -349,7 +328,7 @@ static void *slob_alloc(size_t size, gfp
continue;

/* Attempt to alloc */
- prev = sp->list.prev;
+ prev = sp->lru.prev;
b = slob_page_alloc(sp, size, align);
if (!b)
continue;
@@ -374,8 +353,8 @@ static void *slob_alloc(size_t size, gfp

spin_lock_irqsave(&slob_lock, flags);
sp->units = SLOB_UNITS(PAGE_SIZE);
- sp->free = b;
- INIT_LIST_HEAD(&sp->list);
+ sp->freelist = b;
+ INIT_LIST_HEAD(&sp->lru);
set_slob(b, SLOB_UNITS(PAGE_SIZE), b + SLOB_UNITS(PAGE_SIZE));
set_slob_page_free(sp, slob_list);
b = slob_page_alloc(sp, size, align);
@@ -392,7 +371,7 @@ static void *slob_alloc(size_t size, gfp
*/
static void slob_free(void *block, int size)
{
- struct slob_page *sp;
+ struct page *sp;
slob_t *prev, *next, *b = (slob_t *)block;
slobidx_t units;
unsigned long flags;
@@ -421,7 +400,7 @@ static void slob_free(void *block, int s
if (!slob_page_free(sp)) {
/* This slob page is about to become partially free. Easy! */
sp->units = units;
- sp->free = b;
+ sp->freelist = b;
set_slob(b, units,
(void *)((unsigned long)(b +
SLOB_UNITS(PAGE_SIZE)) & PAGE_MASK));
@@ -441,15 +420,15 @@ static void slob_free(void *block, int s
*/
sp->units += units;

- if (b < sp->free) {
- if (b + units == sp->free) {
- units += slob_units(sp->free);
- sp->free = slob_next(sp->free);
+ if (b < (slob_t *)sp->freelist) {
+ if (b + units == sp->freelist) {
+ units += slob_units(sp->freelist);
+ sp->freelist = slob_next(sp->freelist);
}
- set_slob(b, units, sp->free);
- sp->free = b;
+ set_slob(b, units, sp->freelist);
+ sp->freelist = b;
} else {
- prev = sp->free;
+ prev = sp->freelist;
next = slob_next(prev);
while (b > next) {
prev = next;
@@ -522,7 +501,7 @@ EXPORT_SYMBOL(__kmalloc_node);

void kfree(const void *block)
{
- struct slob_page *sp;
+ struct page *sp;

trace_kfree(_RET_IP_, block);

@@ -536,14 +515,14 @@ void kfree(const void *block)
unsigned int *m = (unsigned int *)(block - align);
slob_free(m, *m + align);
} else
- put_page(&sp->page);
+ put_page(sp);
}
EXPORT_SYMBOL(kfree);

/* can't use ksize for kmem_cache_alloc memory, only kmalloc */
size_t ksize(const void *block)
{
- struct slob_page *sp;
+ struct page *sp;

BUG_ON(!block);
if (unlikely(block == ZERO_SIZE_PTR))
@@ -555,7 +534,7 @@ size_t ksize(const void *block)
unsigned int *m = (unsigned int *)(block - align);
return SLOB_UNITS(*m) * SLOB_UNIT;
} else
- return sp->page.private;
+ return sp->private;
}
EXPORT_SYMBOL(ksize);

Index: linux-2.6/include/linux/mm_types.h
===================================================================
--- linux-2.6.orig/include/linux/mm_types.h 2012-04-11 07:07:16.660129272 -0500
+++ linux-2.6/include/linux/mm_types.h 2012-04-11 07:11:01.944124607 -0500
@@ -52,7 +52,7 @@ struct page {
struct {
union {
pgoff_t index; /* Our offset within mapping. */
- void *freelist; /* slub first free object */
+ void *freelist; /* slub/slob first free object */
};

union {
@@ -80,11 +80,12 @@ struct page {
*/
atomic_t _mapcount;

- struct {
+ struct { /* SLUB */
unsigned inuse:16;
unsigned objects:15;
unsigned frozen:1;
};
+ int units; /* SLOB */
};
atomic_t _count; /* Usage count, see below. */
};