[PATCH] Swap Migration V5: Add CONFIG_MIGRATION for page migration support
Include page migration if the system is NUMA or having a memory model that
allows distinct areas of memory (SPARSEMEM, DISCONTIGMEM).
And:
- Only include lru_add_drain_per_cpu if building for an SMP system.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/Kconfig b/mm/Kconfig
index b3db11f..a9cb80a 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -132,3 +132,10 @@
default "4096" if ARM && !CPU_CACHE_VIPT
default "4096" if PARISC && !PA20
default "4"
+
+#
+# support for page migration
+#
+config MIGRATION
+ def_bool y if NUMA || SPARSEMEM || DISCONTIGMEM
+ depends on SWAP
diff --git a/mm/vmscan.c b/mm/vmscan.c
index a537a7f..58270ae 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -568,6 +568,7 @@
return reclaimed;
}
+#ifdef CONFIG_MIGRATION
/*
* swapout a single page
* page is locked upon entry, unlocked on exit
@@ -656,8 +657,9 @@
/*
* Skip locked pages during the first two passes to give the
- * functions holding the lock time to release the page. Later we use
- * lock_page to have a higher chance of acquiring the lock.
+ * functions holding the lock time to release the page. Later we
+ * use lock_page() to have a higher chance of acquiring the
+ * lock.
*/
if (pass > 2)
lock_page(page);
@@ -669,15 +671,15 @@
* Only wait on writeback if we have already done a pass where
* we we may have triggered writeouts for lots of pages.
*/
- if (pass > 0)
+ if (pass > 0) {
wait_on_page_writeback(page);
- else
+ } else {
if (PageWriteback(page)) {
unlock_page(page);
goto retry_later;
}
+ }
-#ifdef CONFIG_SWAP
if (PageAnon(page) && !PageSwapCache(page)) {
if (!add_to_swap(page)) {
unlock_page(page);
@@ -686,16 +688,15 @@
continue;
}
}
-#endif /* CONFIG_SWAP */
/*
* Page is properly locked and writeback is complete.
* Try to migrate the page.
*/
- if (swap_page(page)) {
+ if (!swap_page(page))
+ continue;
retry_later:
- retry++;
- }
+ retry++;
}
if (retry && pass++ < 10)
goto redo;
@@ -708,6 +709,7 @@
return nr_failed + retry;
}
+#endif
/*
* zone->lru_lock is heavily contended. Some of the functions that