[PATCH] mm: nommu use compound pages
Now that compound page handling is properly fixed in the VM, move nommu
over to using compound pages rather than rolling their own refcounting.
nommu vm page refcounting is broken anyway, but there is no need to have
divergent code in the core VM now, nor when it gets fixed.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: David Howells <dhowells@redhat.com>
(Needs testing, please).
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
index 3f810ac..b1ca234 100644
--- a/fs/ramfs/file-nommu.c
+++ b/fs/ramfs/file-nommu.c
@@ -87,8 +87,7 @@
xpages = 1UL << order;
npages = (newsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
- for (loop = 0; loop < npages; loop++)
- set_page_count(pages + loop, 1);
+ split_page(pages, order);
/* trim off any pages we don't actually require */
for (loop = npages; loop < xpages; loop++)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9b3cdfc..3d84b7a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -327,11 +327,7 @@
void put_page(struct page *page);
-#ifdef CONFIG_MMU
void split_page(struct page *page, unsigned int order);
-#else
-static inline void split_page(struct page *page, unsigned int order) {}
-#endif
/*
* Multiple processes may "see" the same page. E.g. for untouched
diff --git a/mm/internal.h b/mm/internal.h
index e3042db..7bb3397 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -15,19 +15,7 @@
static inline void set_page_refs(struct page *page, int order)
{
-#ifdef CONFIG_MMU
set_page_count(page, 1);
-#else
- int i;
-
- /*
- * We need to reference all the pages for this order, otherwise if
- * anyone accesses one of the pages with (get/put) it will be freed.
- * - eg: access_process_vm()
- */
- for (i = 0; i < (1 << order); i++)
- set_page_count(page + i, 1);
-#endif /* CONFIG_MMU */
}
static inline void __put_page(struct page *page)
diff --git a/mm/nommu.c b/mm/nommu.c
index 4951f47..db45efa 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -159,7 +159,7 @@
/*
* kmalloc doesn't like __GFP_HIGHMEM for some reason
*/
- return kmalloc(size, gfp_mask & ~__GFP_HIGHMEM);
+ return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
}
struct page * vmalloc_to_page(void *addr)
@@ -623,7 +623,7 @@
* - note that this may not return a page-aligned address if the object
* we're allocating is smaller than a page
*/
- base = kmalloc(len, GFP_KERNEL);
+ base = kmalloc(len, GFP_KERNEL|__GFP_COMP);
if (!base)
goto enomem;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7aa0181..e197818 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -422,11 +422,6 @@
mutex_debug_check_no_locks_freed(page_address(page),
PAGE_SIZE<<order);
-#ifndef CONFIG_MMU
- for (i = 1 ; i < (1 << order) ; ++i)
- __put_page(page + i);
-#endif
-
for (i = 0 ; i < (1 << order) ; ++i)
reserved += free_pages_check(page + i);
if (reserved)
@@ -746,7 +741,6 @@
clear_highpage(page + i);
}
-#ifdef CONFIG_MMU
/*
* split_page takes a non-compound higher-order page, and splits it into
* n (1<<order) sub-pages: page[0..n]
@@ -766,7 +760,6 @@
set_page_count(page + i, 1);
}
}
-#endif
/*
* Really, prep_compound_page() should be called from __rmqueue_bulk(). But
diff --git a/mm/slab.c b/mm/slab.c
index f477acf..ff0ab77 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -590,6 +590,8 @@
static inline struct kmem_cache *page_get_cache(struct page *page)
{
+ if (unlikely(PageCompound(page)))
+ page = (struct page *)page_private(page);
return (struct kmem_cache *)page->lru.next;
}
@@ -600,6 +602,8 @@
static inline struct slab *page_get_slab(struct page *page)
{
+ if (unlikely(PageCompound(page)))
+ page = (struct page *)page_private(page);
return (struct slab *)page->lru.prev;
}
@@ -2412,8 +2416,11 @@
struct page *page;
/* Nasty!!!!!! I hope this is OK. */
- i = 1 << cachep->gfporder;
page = virt_to_page(objp);
+
+ i = 1;
+ if (likely(!PageCompound(page)))
+ i <<= cachep->gfporder;
do {
page_set_cache(page, cachep);
page_set_slab(page, slabp);