mm/migration: make isolate_movable_page() return int type

Patch series "HWPOISON: soft offlining for non-lru movable page", v6.

After Minchan's commit bda807d44454 ("mm: migrate: support non-lru
movable page migration"), some type of non-lru page like zsmalloc and
virtio-balloon page also support migration.

Therefore, we can:

1) soft offlining no-lru movable pages, which means when memory
   corrected errors occur on a non-lru movable page, we can stop to use
   it by migrating data onto another page and disable the original
   (maybe half-broken) one.

2) enable memory hotplug for non-lru movable pages, i.e. we may offline
   blocks, which include such pages, by using non-lru page migration.

This patchset is heavily dependent on non-lru movable page migration.

This patch (of 4):

Change the return type of isolate_movable_page() from bool to int.  It
will return 0 when isolate movable page successfully, and return -EBUSY
when it isolates failed.

There is no functional change within this patch but prepare for later
patch.

[xieyisheng1@huawei.com: v6]
Link: http://lkml.kernel.org/r/1486108770-630-2-git-send-email-xieyisheng1@huawei.com
Link: http://lkml.kernel.org/r/1485867981-16037-2-git-send-email-ysxie@foxmail.com
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Suggested-by: Michal Hocko <mhocko@kernel.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index ae8d475..43d5deb 100644 (file)
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -37,7 +37,7 @@ extern int migrate_page(struct address_space *,
                        struct page *, struct page *, enum migrate_mode);
 extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
                unsigned long private, enum migrate_mode mode, int reason);
-extern bool isolate_movable_page(struct page *page, isolate_mode_t mode);
+extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
 extern void putback_movable_page(struct page *page);
 
 extern int migrate_prep(void);

diff --git a/mm/compaction.c b/mm/compaction.c
index 0aa2757..0fdfde0 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -802,7 +802,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
                                        locked = false;
                                }
 
-                               if (isolate_movable_page(page, isolate_mode))
+                               if (!isolate_movable_page(page, isolate_mode))
                                        goto isolate_success;
                        }
 

diff --git a/mm/migrate.c b/mm/migrate.c
index 87f4d0f..6807174 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -74,7 +74,7 @@ int migrate_prep_local(void)
        return 0;
 }
 
-bool isolate_movable_page(struct page *page, isolate_mode_t mode)
+int isolate_movable_page(struct page *page, isolate_mode_t mode)
 {
        struct address_space *mapping;
 
@@ -125,14 +125,14 @@ bool isolate_movable_page(struct page *page, isolate_mode_t mode)
        __SetPageIsolated(page);
        unlock_page(page);
 
-       return true;
+       return 0;
 
 out_no_isolated:
        unlock_page(page);
 out_putpage:
        put_page(page);
 out:
-       return false;
+       return -EBUSY;
 }
 
 /* It should be called on page which is PG_movable */