| Message ID | 20181116083020.20260-5-mhocko@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm, memory_hotplug: improve memory offlining failures debugging | expand |
On Fri, 2018-11-16 at 09:30 +0100, Michal Hocko wrote: > From: Michal Hocko <mhocko@suse.com> > > 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. > > [akpm: tweak messages a bit] > Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Oscar Salvador <osalvador@suse.de>
On 11/16/2018 02:00 PM, Michal Hocko wrote: > From: Michal Hocko <mhocko@suse.com> > > 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. > > [akpm: tweak messages a bit] > Signed-off-by: Michal Hocko <mhocko@suse.com> > --- > mm/memory_hotplug.c | 34 +++++++++++++++++++++++----------- > 1 file changed, 23 insertions(+), 11 deletions(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index a92b1b8f6218..88d50e74e3fe 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1553,6 +1553,7 @@ static int __ref __offline_pages(unsigned long start_pfn, > unsigned long valid_start, valid_end; > struct zone *zone; > struct memory_notify arg; > + char *reason; > > mem_hotplug_begin(); > > @@ -1561,7 +1562,9 @@ static int __ref __offline_pages(unsigned long start_pfn, > if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start, > &valid_end)) { > mem_hotplug_done(); > - return -EINVAL; > + ret = -EINVAL; > + reason = "multizone range"; > + goto failed_removal; > } > > zone = page_zone(pfn_to_page(valid_start)); > @@ -1573,7 +1576,8 @@ static int __ref __offline_pages(unsigned long start_pfn, > MIGRATE_MOVABLE, true); > if (ret) { > mem_hotplug_done(); > - return ret; > + reason = "failure 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 = "notifier failure"; > + goto failed_removal_isolated; > + } > > pfn = start_pfn; > repeat: > /* start memory hot removal */ > ret = -EINTR; > - if (signal_pending(current)) > - goto failed_removal; > + if (signal_pending(current)) { > + reason = "signal backoff"; > + goto failed_removal_isolated; > + } > > cond_resched(); > lru_add_drain_all(); > @@ -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 = "failure to dissolve huge pages"; > + goto failed_removal_isolated; > + } > /* check again */ > offlined_pages = check_pages_isolated(start_pfn, end_pfn); > if (offlined_pages < 0) > @@ -1648,13 +1658,15 @@ static int __ref __offline_pages(unsigned long start_pfn, > mem_hotplug_done(); > return 0; > > +failed_removal_isolated: > + undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); > failed_removal: > - pr_debug("memory offlining [mem %#010llx-%#010llx] failed\n", > + pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n", > (unsigned long long) start_pfn << PAGE_SHIFT, > - ((unsigned long long) end_pfn << PAGE_SHIFT) - 1); > + ((unsigned long long) end_pfn << PAGE_SHIFT) - 1, > + reason); > memory_notify(MEM_CANCEL_OFFLINE, &arg); > /* pushback to free area */ > - undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); > mem_hotplug_done(); > return ret; > } > Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index a92b1b8f6218..88d50e74e3fe 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1553,6 +1553,7 @@ static int __ref __offline_pages(unsigned long start_pfn, unsigned long valid_start, valid_end; struct zone *zone; struct memory_notify arg; + char *reason; mem_hotplug_begin(); @@ -1561,7 +1562,9 @@ static int __ref __offline_pages(unsigned long start_pfn, if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start, &valid_end)) { mem_hotplug_done(); - return -EINVAL; + ret = -EINVAL; + reason = "multizone range"; + goto failed_removal; } zone = page_zone(pfn_to_page(valid_start)); @@ -1573,7 +1576,8 @@ static int __ref __offline_pages(unsigned long start_pfn, MIGRATE_MOVABLE, true); if (ret) { mem_hotplug_done(); - return ret; + reason = "failure 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 = "notifier failure"; + goto failed_removal_isolated; + } pfn = start_pfn; repeat: /* start memory hot removal */ ret = -EINTR; - if (signal_pending(current)) - goto failed_removal; + if (signal_pending(current)) { + reason = "signal backoff"; + goto failed_removal_isolated; + } cond_resched(); lru_add_drain_all(); @@ -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 = "failure to dissolve huge pages"; + goto failed_removal_isolated; + } /* check again */ offlined_pages = check_pages_isolated(start_pfn, end_pfn); if (offlined_pages < 0) @@ -1648,13 +1658,15 @@ static int __ref __offline_pages(unsigned long start_pfn, mem_hotplug_done(); return 0; +failed_removal_isolated: + undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); failed_removal: - pr_debug("memory offlining [mem %#010llx-%#010llx] failed\n", + pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n", (unsigned long long) start_pfn << PAGE_SHIFT, - ((unsigned long long) end_pfn << PAGE_SHIFT) - 1); + ((unsigned long long) end_pfn << PAGE_SHIFT) - 1, + reason); memory_notify(MEM_CANCEL_OFFLINE, &arg); /* pushback to free area */ - undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); mem_hotplug_done(); return ret; }