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-rw-r--r--include/linux/page_ext.h2
-rw-r--r--mm/page_alloc.c2
-rw-r--r--mm/page_ext.c41
3 files changed, 34 insertions, 11 deletions
diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h
index 03f2a3e7d76d..179bdc4a470c 100644
--- a/include/linux/page_ext.h
+++ b/include/linux/page_ext.h
@@ -7,6 +7,8 @@
struct pglist_data;
struct page_ext_operations {
+ size_t offset;
+ size_t size;
bool (*need)(void);
void (*init)(void);
};
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 06ea805d1b14..b0f133f2c655 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -687,7 +687,7 @@ static inline void clear_page_guard(struct zone *zone, struct page *page,
__mod_zone_freepage_state(zone, (1 << order), migratetype);
}
#else
-struct page_ext_operations debug_guardpage_ops = { NULL, };
+struct page_ext_operations debug_guardpage_ops;
static inline bool set_page_guard(struct zone *zone, struct page *page,
unsigned int order, int migratetype) { return false; }
static inline void clear_page_guard(struct zone *zone, struct page *page,
diff --git a/mm/page_ext.c b/mm/page_ext.c
index 16292829c5c5..121dcffc4ec1 100644
--- a/mm/page_ext.c
+++ b/mm/page_ext.c
@@ -42,6 +42,11 @@
* and page extension core can skip to allocate memory. As result,
* none of memory is wasted.
*
+ * When need callback returns true, page_ext checks if there is a request for
+ * extra memory through size in struct page_ext_operations. If it is non-zero,
+ * extra space is allocated for each page_ext entry and offset is returned to
+ * user through offset in struct page_ext_operations.
+ *
* The init callback is used to do proper initialization after page extension
* is completely initialized. In sparse memory system, extra memory is
* allocated some time later than memmap is allocated. In other words, lifetime
@@ -66,18 +71,24 @@ static struct page_ext_operations *page_ext_ops[] = {
};
static unsigned long total_usage;
+static unsigned long extra_mem;
static bool __init invoke_need_callbacks(void)
{
int i;
int entries = ARRAY_SIZE(page_ext_ops);
+ bool need = false;
for (i = 0; i < entries; i++) {
- if (page_ext_ops[i]->need && page_ext_ops[i]->need())
- return true;
+ if (page_ext_ops[i]->need && page_ext_ops[i]->need()) {
+ page_ext_ops[i]->offset = sizeof(struct page_ext) +
+ extra_mem;
+ extra_mem += page_ext_ops[i]->size;
+ need = true;
+ }
}
- return false;
+ return need;
}
static void __init invoke_init_callbacks(void)
@@ -91,6 +102,16 @@ static void __init invoke_init_callbacks(void)
}
}
+static unsigned long get_entry_size(void)
+{
+ return sizeof(struct page_ext) + extra_mem;
+}
+
+static inline struct page_ext *get_entry(void *base, unsigned long index)
+{
+ return base + get_entry_size() * index;
+}
+
#if !defined(CONFIG_SPARSEMEM)
@@ -121,7 +142,7 @@ struct page_ext *lookup_page_ext(struct page *page)
#endif
index = pfn - round_down(node_start_pfn(page_to_nid(page)),
MAX_ORDER_NR_PAGES);
- return base + index;
+ return get_entry(base, index);
}
static int __init alloc_node_page_ext(int nid)
@@ -143,7 +164,7 @@ static int __init alloc_node_page_ext(int nid)
!IS_ALIGNED(node_end_pfn(nid), MAX_ORDER_NR_PAGES))
nr_pages += MAX_ORDER_NR_PAGES;
- table_size = sizeof(struct page_ext) * nr_pages;
+ table_size = get_entry_size() * nr_pages;
base = memblock_virt_alloc_try_nid_nopanic(
table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
@@ -196,7 +217,7 @@ struct page_ext *lookup_page_ext(struct page *page)
if (!section->page_ext)
return NULL;
#endif
- return section->page_ext + pfn;
+ return get_entry(section->page_ext, pfn);
}
static void *__meminit alloc_page_ext(size_t size, int nid)
@@ -229,7 +250,7 @@ static int __meminit init_section_page_ext(unsigned long pfn, int nid)
if (section->page_ext)
return 0;
- table_size = sizeof(struct page_ext) * PAGES_PER_SECTION;
+ table_size = get_entry_size() * PAGES_PER_SECTION;
base = alloc_page_ext(table_size, nid);
/*
@@ -249,7 +270,7 @@ static int __meminit init_section_page_ext(unsigned long pfn, int nid)
* we need to apply a mask.
*/
pfn &= PAGE_SECTION_MASK;
- section->page_ext = base - pfn;
+ section->page_ext = (void *)base - get_entry_size() * pfn;
total_usage += table_size;
return 0;
}
@@ -262,7 +283,7 @@ static void free_page_ext(void *addr)
struct page *page = virt_to_page(addr);
size_t table_size;
- table_size = sizeof(struct page_ext) * PAGES_PER_SECTION;
+ table_size = get_entry_size() * PAGES_PER_SECTION;
BUG_ON(PageReserved(page));
free_pages_exact(addr, table_size);
@@ -277,7 +298,7 @@ static void __free_page_ext(unsigned long pfn)
ms = __pfn_to_section(pfn);
if (!ms || !ms->page_ext)
return;
- base = ms->page_ext + pfn;
+ base = get_entry(ms->page_ext, pfn);
free_page_ext(base);
ms->page_ext = NULL;
}