Re: [PATCH 2/5] Swapless V2: Add migration swap entries

[Christoph Lameter <clameter@sgi.com>]

1. Add explanation for the yield

2. Move unlikely to is_migration_entry (Does that really work??)

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.17-rc1-mm2/mm/memory.c
===================================================================
--- linux-2.6.17-rc1-mm2.orig/mm/memory.c	2006-04-13 16:43:10.000000000 -0700
+++ linux-2.6.17-rc1-mm2/mm/memory.c	2006-04-13 17:32:36.000000000 -0700
@@ -1880,7 +1880,11 @@ static int do_swap_page(struct mm_struct
 
 	entry = pte_to_swp_entry(orig_pte);
 
-	if (unlikely(is_migration_entry(entry))) {
+	if (is_migration_entry(entry)) {
+		/*
+		 * We cannot access the page because of ongoing page
+		 * migration. See if we can do something else.
+		 */
 		yield();
 		goto out;
 	}
Index: linux-2.6.17-rc1-mm2/include/linux/swapops.h
===================================================================
--- linux-2.6.17-rc1-mm2.orig/include/linux/swapops.h	2006-04-13 16:43:10.000000000 -0700
+++ linux-2.6.17-rc1-mm2/include/linux/swapops.h	2006-04-13 17:32:58.000000000 -0700
@@ -77,7 +77,7 @@ static inline swp_entry_t make_migration
 
 static inline int is_migration_entry(swp_entry_t entry)
 {
-	return swp_type(entry) == SWP_TYPE_MIGRATION;
+	return unlikely(swp_type(entry) == SWP_TYPE_MIGRATION);
 }
 
 static inline struct page *migration_entry_to_page(swp_entry_t entry)
-
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