The patch titled
Implement lookup_swap_cache for migration entries
has been removed from the -mm tree. Its filename is
swapless-v2-add-migration-swap-entries-fix.patch
This patch was probably dropped from -mm because
it has now been merged into a subsystem tree or
into Linus's tree, or because it was folded into
its parent patch in the -mm tree.
From: Christoph Lameter <clameter@xxxxxxx>
This undoes the optimization that resulted in a yield in do_swap_cache().
do_swap_cache() stays as is. Instead we convert the migration entry to a
page * in lookup_swap_cache.
For the non swap case we need a special macro version of lookup_swap_cache
that is only capable of handling migration cache entries.
Signed-off-by: Christoph Lameter <claemter@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/linux/swap.h | 14 +++++++++++++-
include/linux/swapops.h | 2 +-
mm/memory.c | 5 -----
mm/swap_state.c | 7 +++++++
4 files changed, 21 insertions(+), 7 deletions(-)
diff -puN include/linux/swap.h~swapless-v2-add-migration-swap-entries-fix include/linux/swap.h
--- devel/include/linux/swap.h~swapless-v2-add-migration-swap-entries-fix 2006-04-14 22:02:32.000000000 -0700
+++ devel-akpm/include/linux/swap.h 2006-04-14 22:07:19.000000000 -0700
@@ -300,7 +300,6 @@ static inline void disable_swap_token(vo
#define swap_duplicate(swp) /*NOTHING*/
#define swap_free(swp) /*NOTHING*/
#define read_swap_cache_async(swp,vma,addr) NULL
-#define lookup_swap_cache(swp) NULL
#define valid_swaphandles(swp, off) 0
#define can_share_swap_page(p) 0
#define move_to_swap_cache(p, swp) 1
@@ -309,6 +308,19 @@ static inline void disable_swap_token(vo
#define delete_from_swap_cache(p) /*NOTHING*/
#define swap_token_default_timeout 0
+/*
+ * Must use a macro for lookup_swap_cache since the functions
+ * used are only available in certain contexts.
+ */
+#define lookup_swap_cache(__swp) \
+({ struct page *p = NULL; \
+ if (is_migration_entry(__swp)) { \
+ p = migration_entry_to_page(__swp); \
+ get_page(p); \
+ } \
+ p; \
+})
+
static inline int remove_exclusive_swap_page(struct page *p)
{
return 0;
diff -puN include/linux/swapops.h~swapless-v2-add-migration-swap-entries-fix include/linux/swapops.h
--- devel/include/linux/swapops.h~swapless-v2-add-migration-swap-entries-fix 2006-04-14 22:02:32.000000000 -0700
+++ devel-akpm/include/linux/swapops.h 2006-04-14 22:07:19.000000000 -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)
diff -puN mm/memory.c~swapless-v2-add-migration-swap-entries-fix mm/memory.c
--- devel/mm/memory.c~swapless-v2-add-migration-swap-entries-fix 2006-04-14 22:02:32.000000000 -0700
+++ devel-akpm/mm/memory.c 2006-04-14 22:02:32.000000000 -0700
@@ -1880,11 +1880,6 @@ static int do_swap_page(struct mm_struct
entry = pte_to_swp_entry(orig_pte);
- if (unlikely(is_migration_entry(entry))) {
- yield();
- goto out;
- }
-
page = lookup_swap_cache(entry);
if (!page) {
swapin_readahead(entry, address, vma);
diff -puN mm/swap_state.c~swapless-v2-add-migration-swap-entries-fix mm/swap_state.c
--- devel/mm/swap_state.c~swapless-v2-add-migration-swap-entries-fix 2006-04-14 22:02:32.000000000 -0700
+++ devel-akpm/mm/swap_state.c 2006-04-14 22:02:32.000000000 -0700
@@ -12,6 +12,7 @@
#include <linux/swap.h>
#include <linux/init.h>
#include <linux/pagemap.h>
+#include <linux/swapops.h>
#include <linux/buffer_head.h>
#include <linux/backing-dev.h>
#include <linux/pagevec.h>
@@ -299,6 +300,12 @@ struct page * lookup_swap_cache(swp_entr
{
struct page *page;
+ if (is_migration_entry(entry)) {
+ page = migration_entry_to_page(entry);
+ get_page(page);
+ return page;
+ }
+
page = find_get_page(&swapper_space, entry.val);
if (page)
_
Patches currently in -mm which might be from clameter@xxxxxxx are
origin.patch
page-migration-make-do_swap_page-redo-the-fault.patch
slab-extract-cache_free_alien-from-__cache_free.patch
migration-remove-unnecessary-pageswapcache-checks.patch
migration-remove-unnecessary-pageswapcache-checks-fix.patch
swapless-v2-try_to_unmap-rename-ignrefs-to-migration.patch
swapless-v2-add-migration-swap-entries.patch
swapless-v2-add-migration-swap-entries-fix.patch
swapless-v2-make-try_to_unmap-create-migration-entries.patch
swapless-v2-rip-out-swap-portion-of-old-migration-code.patch
swapless-v2-revise-main-migration-logic.patch
preserve-write-permissions-in-migration-entries.patch
-
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