[2/6] Xen VMM #4: return code for arch_free_page

[Ian Pratt]

This patch adds a return value to the existing arch_free_page function
that indicates whether the normal free routine still has work to
do. The only architecture that currently uses arch_free_page is arch
'um'. arch xen needs this for 'foreign pages' - pages that don't
belong to the page allocator but are instead managed by custom
allocators. Such pages are marked using PG_arch_1.

Signed-off-by: ian.pratt@xxxxxxxxxxxx

---


diff -Nurp pristine-linux-2.6.10-rc3/include/linux/gfp.h tmp-linux-2.6.10-rc3-xen.patch/include/linux/gfp.h
--- pristine-linux-2.6.10-rc3/include/linux/gfp.h	2004-12-03 21:53:07.000000000 +0000
+++ tmp-linux-2.6.10-rc3-xen.patch/include/linux/gfp.h	2004-12-08 00:52:40.000000000 +0000
@@ -74,8 +74,12 @@ struct vm_area_struct;
  * optimized to &contig_page_data at compile-time.
  */
 
+/*
+ * If arch_free_page returns non-zero then the generic free_page code can
+ * immediately bail: the arch-specific function has done all the work.
+ */
 #ifndef HAVE_ARCH_FREE_PAGE
-static inline void arch_free_page(struct page *page, int order) { }
+#define arch_free_page(page, order) 0
 #endif
 
 extern struct page *
diff -Nurp pristine-linux-2.6.10-rc3/mm/page_alloc.c tmp-linux-2.6.10-rc3-xen.patch/mm/page_alloc.c
--- pristine-linux-2.6.10-rc3/mm/page_alloc.c	2004-12-03 21:52:41.000000000 +0000
+++ tmp-linux-2.6.10-rc3-xen.patch/mm/page_alloc.c	2004-12-08 00:56:48.000000000 +0000
@@ -278,7 +278,8 @@ void __free_pages_ok(struct page *page, 
 	LIST_HEAD(list);
 	int i;
 
-	arch_free_page(page, order);
+	if (arch_free_page(page, order))
+		return;
 
 	mod_page_state(pgfree, 1 << order);
 	for (i = 0 ; i < (1 << order) ; ++i)
@@ -508,7 +509,8 @@ static void fastcall free_hot_cold_page(
 	struct per_cpu_pages *pcp;
 	unsigned long flags;
 
-	arch_free_page(page, 0);
+	if (arch_free_page(page, 0))
+		return;
 
 	kernel_map_pages(page, 1, 0);
 	inc_page_state(pgfree);
diff -Nurp pristine-linux-2.6.10-rc2/arch/um/kernel/physmem.c tmp-linux-2.6.10-rc2-xen.patch/arch/um/kernel/physmem.c
--- pristine-linux-2.6.10-rc2/arch/um/kernel/physmem.c	2004-11-19 20:04:30.000000000 +0000
+++ tmp-linux-2.6.10-rc2-xen.patch/arch/um/kernel/physmem.c	2004-11-19 20:05:33.000000000 +0000
@@ -225,7 +225,7 @@ EXPORT_SYMBOL(physmem_forget_descriptor)
 EXPORT_SYMBOL(physmem_remove_mapping);
 EXPORT_SYMBOL(physmem_subst_mapping);
 
-void arch_free_page(struct page *page, int order)
+void __arch_free_page(struct page *page, int order)
 {
 	void *virt;
 	int i;
diff -Nurp pristine-linux-2.6.10-rc2/include/asm-um/page.h tmp-linux-2.6.10-rc2-xen.patch/include/asm-um/page.h
--- pristine-linux-2.6.10-rc2/include/asm-um/page.h	2004-11-19 20:04:52.000000000 +0000
+++ tmp-linux-2.6.10-rc2-xen.patch/include/asm-um/page.h	2004-11-19 20:05:33.000000000 +0000
@@ -46,7 +46,8 @@ extern void *to_virt(unsigned long phys)
 extern struct page *arch_validate(struct page *page, int mask, int order);
 #define HAVE_ARCH_VALIDATE
 
-extern void arch_free_page(struct page *page, int order);
+extern void __arch_free_page(struct page *page, int order);
+#define arch_free_page(page, order) (__arch_free_page((page), (order)), 0)
 #define HAVE_ARCH_FREE_PAGE
 
 #endif

-
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