On Wed 07-11-18 14:04:13, Andrew Morton wrote:
> On Wed, 7 Nov 2018 11:18:29 +0100 Michal Hocko <mhocko@xxxxxxxxxx> wrote:
>
> > From: Michal Hocko <mhocko@xxxxxxxx>
> >
> > The memory offlining failure reporting is inconsistent and insufficient.
> > Some error paths simply do not report the failure to the log at all.
> > When we do report there are no details about the reason of the failure
> > and there are several of them which makes memory offlining failures
> > hard to debug.
> >
> > Make sure that the
> > memory offlining [mem %#010llx-%#010llx] failed
> > message is printed for all failures and also provide a short textual
> > reason for the failure e.g.
> >
> > [ 1984.506184] rac1 kernel: memory offlining [mem 0x82600000000-0x8267fffffff] failed due to signal backoff
> >
> > this tells us that the offlining has failed because of a signal pending
> > aka user intervention.
> >
> > ...
>
> Some of these messages will come out looking a bit odd.
>
> > @@ -1573,7 +1576,8 @@ static int __ref __offline_pages(unsigned long start_pfn,
> > MIGRATE_MOVABLE, true);
> > if (ret) {
> > mem_hotplug_done();
> > - return ret;
> > + reason = "failed to isolate range";
>
> "memory offlining [mem ...] failed due to failed to isolate range"
>
> > + goto failed_removal
> > }
> >
> > arg.start_pfn = start_pfn;
> > @@ -1582,15 +1586,19 @@ static int __ref __offline_pages(unsigned long start_pfn,
> >
> > ret = memory_notify(MEM_GOING_OFFLINE, &arg);
> > ret = notifier_to_errno(ret);
> > - if (ret)
> > - goto failed_removal;
> > + if (ret) {
> > + reason = "notifiers failure";
>
> "memory offlining [mem ...] failed due to notifiers failure"
>
> > @@ -1607,8 +1615,10 @@ static int __ref __offline_pages(unsigned long start_pfn,
> > * actually in order to make hugetlbfs's object counting consistent.
> > */
> > ret = dissolve_free_huge_pages(start_pfn, end_pfn);
> > - if (ret)
> > - goto failed_removal;
> > + if (ret) {
> > + reason = "fails to disolve hugetlb pages";
>
> "memory offlining [mem ...] failed due to fails to disolve hugetlb pages"
>
>
> Fix:
>
> --- a/mm/memory_hotplug.c~mm-memory_hotplug-print-reason-for-the-offlining-failure-fix
> +++ a/mm/memory_hotplug.c
> @@ -1576,7 +1576,7 @@ static int __ref __offline_pages(unsigne
> MIGRATE_MOVABLE, true);
> if (ret) {
> mem_hotplug_done();
> - reason = "failed to isolate range";
> + reason = "failure to isolate range";
> goto failed_removal
> }
0day has noticed the missing ; here.
Andrew, could you pick up the follow up fix please?
commit 614212af5c20126aea1edaceb78aa586e19802cf
Author: Michal Hocko <mhocko@xxxxxxxx>
Date: Tue Nov 13 09:01:50 2018 +0100
fold me "mm, memory_hotplug: print reason for the offlining failure"
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index f5f1b2a27cb3..c82193db4be6 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1581,7 +1581,7 @@ static int __ref __offline_pages(unsigned long start_pfn,
if (ret) {
mem_hotplug_done();
reason = "failure to isolate range";
- goto failed_removal
+ goto failed_removal;
}
arg.start_pfn = start_pfn;
--
Michal Hocko
SUSE Labs
