When migration failure in do_migrate_range() and then the
scan_movable_pages() will most likely return the same movable pfn.
In this case, there is no condition to bail out, they will
always run like this:
...
[878020.623959] migrating pfn 1727813 failed ret:1
[878020.623960] page:00000000faa9673c refcount:3 mapcount:0 mapping:00000000144ccd79 index:0x14280025 pfn:0x1727813
[878020.623962] memcg:ffffa0ff82d5a000
[878020.623962] aops:def_blk_aops ino:fd00001
[878020.623964] flags: 0x17ffffc000206a(referenced|dirty|active|workingset|private|node=0|zone=2|lastcpupid=0x1fffff)
[878020.623966] raw: 0017ffffc000206a ffffb0d14f50fbd8 ffffb0d14f50fbd8 ffffa0ff9c155018
[878020.623967] raw: 0000000014280025 ffffa10327d702d8 00000003ffffffff ffffa0ff82d5a000
[878020.623968] page dumped because: migration failure
[878020.626196] migrating pfn 1727813 failed ret:1
[878020.626198] page:00000000faa9673c refcount:3 mapcount:0 mapping:00000000144ccd79 index:0x14280025 pfn:0x1727813
[878020.626200] memcg:ffffa0ff82d5a000
[878020.626200] aops:def_blk_aops ino:fd00001
[878020.626202] flags: 0x17ffffc000206a(referenced|dirty|active|workingset|private|node=0|zone=2|lastcpupid=0x1fffff)
[878020.626204] raw: 0017ffffc000206a ffffb0d14f50fbd8 ffffb0d14f50fbd8 ffffa0ff9c155018
[878020.626205] raw: 0000000014280025 ffffa10327d702d8 00000003ffffffff ffffa0ff82d5a000
[878020.626206] page dumped because: migration failure
...
Bail out when migration failures reach 3 times.
Fixes: bb8965bd82fd ("mm, memory_hotplug: deobfuscate migration part of offlining")
Signed-off-by: Yajun Deng <yajun.deng@xxxxxxxxx>
---
mm/memory_hotplug.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 8e0fa209d533..72dd385b8892 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1800,11 +1800,12 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages,
struct zone *zone, struct memory_group *group)
{
const unsigned long end_pfn = start_pfn + nr_pages;
- unsigned long pfn, system_ram_pages = 0;
+ unsigned long pfn, tmp_pfn, system_ram_pages = 0;
const int node = zone_to_nid(zone);
unsigned long flags;
struct memory_notify arg;
char *reason;
+ int count = 0;
int ret;
/*
@@ -1887,12 +1888,20 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages,
cond_resched();
+ tmp_pfn = pfn;
ret = scan_movable_pages(pfn, end_pfn, &pfn);
if (!ret) {
- /*
- * TODO: fatal migration failures should bail
- * out
- */
+ if (pfn == tmp_pfn)
+ count++;
+ else
+ count = 0;
+
+ if (unlikely(count == 3)) {
+ ret = -EBUSY;
+ reason = "migration failure";
+ goto failed_removal_isolated;
+ }
+
do_migrate_range(pfn, end_pfn);
}
} while (!ret);
--
2.25.1
