The patch titled
Subject: mm: introduce compaction and migration for ballooned pages
has been added to the -mm tree. Its filename is
mm-introduce-compaction-and-migration-for-ballooned-pages.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Rafael Aquini <aquini@xxxxxxxxxx>
Subject: mm: introduce compaction and migration for ballooned pages
Memory fragmentation introduced by ballooning might reduce significantly
the number of 2MB contiguous memory blocks that can be used within a
guest, thus imposing performance penalties associated with the reduced
number of transparent huge pages that could be used by the guest workload.
This patch introduces the helper functions as well as the necessary
changes to teach compaction and migration bits how to cope with pages
which are part of a guest memory balloon, in order to make them movable by
memory compaction procedures.
Signed-off-by: Rafael Aquini <aquini@xxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 21 +++++++++++++++++++--
mm/migrate.c | 36 ++++++++++++++++++++++++++++++++++--
2 files changed, 53 insertions(+), 4 deletions(-)
diff -puN mm/compaction.c~mm-introduce-compaction-and-migration-for-ballooned-pages mm/compaction.c
--- a/mm/compaction.c~mm-introduce-compaction-and-migration-for-ballooned-pages
+++ a/mm/compaction.c
@@ -14,6 +14,7 @@
#include <linux/backing-dev.h>
#include <linux/sysctl.h>
#include <linux/sysfs.h>
+#include <linux/balloon_compaction.h>
#include "internal.h"
#if defined CONFIG_COMPACTION || defined CONFIG_CMA
@@ -565,9 +566,24 @@ isolate_migratepages_range(struct zone *
goto next_pageblock;
}
- /* Check may be lockless but that's ok as we recheck later */
- if (!PageLRU(page))
+ /*
+ * Check may be lockless but that's ok as we recheck later.
+ * It's possible to migrate LRU pages and balloon pages
+ * Skip any other type of page
+ */
+ if (!PageLRU(page)) {
+ if (unlikely(balloon_page_movable(page))) {
+ if (locked && balloon_page_isolate(page)) {
+ /* Successfully isolated */
+ cc->finished_update_migrate = true;
+ list_add(&page->lru, migratelist);
+ cc->nr_migratepages++;
+ nr_isolated++;
+ goto check_compact_cluster;
+ }
+ }
continue;
+ }
/*
* PageLRU is set. lru_lock normally excludes isolation
@@ -621,6 +637,7 @@ isolate_migratepages_range(struct zone *
cc->nr_migratepages++;
nr_isolated++;
+check_compact_cluster:
/* Avoid isolating too much */
if (cc->nr_migratepages == COMPACT_CLUSTER_MAX) {
++low_pfn;
diff -puN mm/migrate.c~mm-introduce-compaction-and-migration-for-ballooned-pages mm/migrate.c
--- a/mm/migrate.c~mm-introduce-compaction-and-migration-for-ballooned-pages
+++ a/mm/migrate.c
@@ -35,6 +35,7 @@
#include <linux/hugetlb.h>
#include <linux/hugetlb_cgroup.h>
#include <linux/gfp.h>
+#include <linux/balloon_compaction.h>
#include <asm/tlbflush.h>
@@ -79,7 +80,10 @@ void putback_lru_pages(struct list_head
list_del(&page->lru);
dec_zone_page_state(page, NR_ISOLATED_ANON +
page_is_file_cache(page));
- putback_lru_page(page);
+ if (unlikely(balloon_page_movable(page)))
+ balloon_page_putback(page);
+ else
+ putback_lru_page(page);
}
}
@@ -778,6 +782,18 @@ static int __unmap_and_move(struct page
}
}
+ if (unlikely(balloon_page_movable(page))) {
+ /*
+ * A ballooned page does not need any special attention from
+ * physical to virtual reverse mapping procedures.
+ * Skip any attempt to unmap PTEs or to remap swap cache,
+ * in order to avoid burning cycles at rmap level, and perform
+ * the page migration right away (proteced by page lock).
+ */
+ rc = balloon_page_migrate(newpage, page, mode);
+ goto uncharge;
+ }
+
/*
* Corner case handling:
* 1. When a new swap-cache page is read into, it is added to the LRU
@@ -814,7 +830,9 @@ skip_unmap:
put_anon_vma(anon_vma);
uncharge:
- mem_cgroup_end_migration(mem, page, newpage, rc == MIGRATEPAGE_SUCCESS);
+ mem_cgroup_end_migration(mem, page, newpage,
+ (rc == MIGRATEPAGE_SUCCESS ||
+ rc == MIGRATEPAGE_BALLOON_SUCCESS));
unlock:
unlock_page(page);
out:
@@ -846,6 +864,20 @@ static int unmap_and_move(new_page_t get
goto out;
rc = __unmap_and_move(page, newpage, force, offlining, mode);
+
+ if (unlikely(rc == MIGRATEPAGE_BALLOON_SUCCESS)) {
+ /*
+ * A ballooned page has been migrated already.
+ * Now, it's the time to remove the old page from the isolated
+ * pageset list and handle it back to Buddy, wrap-up counters
+ * and return.
+ */
+ dec_zone_page_state(page, NR_ISOLATED_ANON +
+ page_is_file_cache(page));
+ put_page(page);
+ __free_page(page);
+ return 0;
+ }
out:
if (rc != -EAGAIN) {
/*
_
Patches currently in -mm which might be from aquini@xxxxxxxxxx are
mm-adjust-address_space_operationsmigratepage-return-code.patch
mm-redefine-address_spaceassoc_mapping.patch
mm-introduce-a-common-interface-for-balloon-pages-mobility.patch
mm-introduce-compaction-and-migration-for-ballooned-pages.patch
virtio_balloon-introduce-migration-primitives-to-balloon-pages.patch
mm-introduce-putback_movable_pages.patch
mm-add-vm-event-counters-for-balloon-pages-compaction.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
