[Xen-devel] [RFC PATCH v1 01/33] mm: introduce common help functions to deal with reserved/managed pages

[Jiang Liu <liuj97@xxxxxxxxx>]

Code to deal with reserved/managed pages are duplicated by many
architectures, so introduce common help functions to reduce duplicated
code. These common help functions will also be used to concentrate code
to modify totalram_pages and zone->managed_pages, which makes the code
much more clear.

Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
---
 include/linux/mm.h |   37 +++++++++++++++++++++++++++++++++++++
 mm/page_alloc.c    |   20 ++++++++++++++++++++
 2 files changed, 57 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7acc9dc..881461c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1295,6 +1295,43 @@ extern void free_area_init_node(int nid, unsigned long * 
zones_size,
                unsigned long zone_start_pfn, unsigned long *zholes_size);
 extern void free_initmem(void);
 
+/* Help functions to deal with reserved/managed pages. */
+extern unsigned long free_reserved_area(unsigned long start, unsigned long end,
+                                       int poison, char *s);
+
+static inline void adjust_managed_page_count(struct page *page, long count)
+{
+       totalram_pages += count;
+}
+
+static inline void __free_reserved_page(struct page *page)
+{
+       ClearPageReserved(page);
+       init_page_count(page);
+       __free_page(page);
+}
+
+static inline void free_reserved_page(struct page *page)
+{
+       __free_reserved_page(page);
+       adjust_managed_page_count(page, 1);
+}
+
+static inline void mark_page_reserved(struct page *page)
+{
+       SetPageReserved(page);
+       adjust_managed_page_count(page, -1);
+}
+
+static inline void free_initmem_default(int poison)
+{
+       extern char __init_begin[], __init_end[];
+
+       free_reserved_area(PAGE_ALIGN((unsigned long)&__init_begin) ,
+                          ((unsigned long)&__init_end) & PAGE_MASK,
+                          poison, "unused kernel");
+}
+
 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 /*
  * With CONFIG_HAVE_MEMBLOCK_NODE_MAP set, an architecture may initialise its
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8fcced7..0fadb09 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5113,6 +5113,26 @@ early_param("movablecore", cmdline_parse_movablecore);
 
 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
 
+unsigned long free_reserved_area(unsigned long start, unsigned long end,
+                                int poison, char *s)
+{
+       unsigned long pages, pos;
+
+       pos = start = PAGE_ALIGN(start);
+       end &= PAGE_MASK;
+       for (pages = 0; pos < end; pos += PAGE_SIZE, pages++) {
+               if (poison)
+                       memset((void *)pos, poison, PAGE_SIZE);
+               free_reserved_page(virt_to_page(pos));
+       }
+
+       if (pages && s)
+               pr_info("Freeing %s memory: %ldK (%lx - %lx)\n",
+                       s, pages << (PAGE_SHIFT - 10), start, end);
+
+       return pages;
+}
+
 /**
  * set_dma_reserve - set the specified number of pages reserved in the first 
zone
  * @new_dma_reserve: The number of pages to mark reserved
-- 
1.7.9.5


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel