From: David Hildenbrand <david@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, x86@kernel.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Tony Luck <tony.luck@intel.com>,
Fenghua Yu <fenghua.yu@intel.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Rich Felker <dalias@libc.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Mark Rutland <mark.rutland@arm.com>,
Steve Capper <steve.capper@arm.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Yu Zhao <yuzhao@google.com>, Jun Yao <yaojun8558363@gmail.com>,
Robin Murphy <robin.murphy@arm.com>,
Michal Hocko <mhocko@suse.com>,
Oscar Salvador <osalvador@suse.de>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
Christophe Leroy <christophe.leroy@c-s.fr>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Gerald Schaefer <gerald.schaefer@de.ibm.com>,
Halil Pasic <pasic@linux.ibm.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Dan Williams <dan.j.williams@intel.com>,
Wei Yang <richard.weiyang@gmail.com>, Qian Cai <cai@lca.pw>,
Jason Gunthorpe <jgg@ziepe.ca>,
Logan Gunthorpe <logang@deltatee.com>,
Ira Weiny <ira.weiny@intel.com>
Subject: Re: [PATCH v6 05/10] mm/memory_hotplug: Shrink zones when offlining memory
Date: Wed, 18 Dec 2019 18:08:04 +0100 [thread overview]
Message-ID: <4a3d7420-2d11-a37c-0e82-2096fbf7bca6@redhat.com> (raw)
In-Reply-To: <20191130152159.258fa331542fc693e24723eb@linux-foundation.org>
On 01.12.19 00:21, Andrew Morton wrote:
> On Sun, 27 Oct 2019 23:45:52 +0100 David Hildenbrand <david@redhat.com> wrote:
>
>> I think I just found an issue with try_offline_node().
>> try_offline_node() is pretty much broken already (touches garbage
>> memmaps and will not considers mixed NIDs within sections), however,
>> relies on the node span to look for memory sections to probe. So it
>> seems to rely on the nodes getting shrunk when removing memory, not when
>> offlining.
>>
>> As we shrink the node span when offlining now and not when removing,
>> this can go wrong once we offline the last memory block of the node and
>> offline the last CPU. We could still have memory around that we could
>> re-online, however, the node would already be offline. Unlikely, but
>> possible.
>>
>> Note that the same is also broken without this patch in case memory is
>> never onlined. The "pfn_to_nid(pfn) != nid" can easily succeed on the
>> garbage memmap, resulting in no memory being detected as belonging to
>> the node. Also, resize_pgdat_range() is called when onlining memory, not
>> when adding it. :/ Oh this is so broken :)
>>
>> The right fix is probably to walk over all memory blocks that could
>> exist and test if they belong to the nid (if offline, check the
>> block->nid, if online check all pageblocks). A fix we can then move in
>> front of this patch.
>>
>> Will look into this this week.
>
> And this series shows almost no sign of having been reviewed. I'll hold
> it over for 5.6.
>
Hi Andrew, any chance we can get the (now at least reviewed - thx Oscar)
fix in patch #5 into 5.5? (I want to do the final stable backports for
the uninitialized memmap stuff)
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2019-12-18 17:08 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-06 8:56 [PATCH v6 00/10] mm/memory_hotplug: Shrink zones before removing memory David Hildenbrand
2019-10-06 8:56 ` [PATCH v6 01/10] mm/memunmap: Don't access uninitialized memmap in memunmap_pages() David Hildenbrand
2019-10-06 19:58 ` Damian Tometzki
2019-10-06 20:13 ` David Hildenbrand
2019-10-14 9:05 ` David Hildenbrand
2019-10-06 8:56 ` [PATCH v6 02/10] mm/memmap_init: Update variable name in memmap_init_zone David Hildenbrand
2019-10-06 8:56 ` [PATCH v6 03/10] mm/memory_hotplug: Don't access uninitialized memmaps in shrink_pgdat_span() David Hildenbrand
2019-10-14 9:31 ` David Hildenbrand
2019-10-06 8:56 ` [PATCH v6 04/10] mm/memory_hotplug: Don't access uninitialized memmaps in shrink_zone_span() David Hildenbrand
2019-10-14 9:32 ` David Hildenbrand
2019-10-14 19:17 ` Andrew Morton
2019-11-19 14:16 ` David Hildenbrand
2019-11-19 20:44 ` Andrew Morton
2019-10-06 8:56 ` [PATCH v6 05/10] mm/memory_hotplug: Shrink zones when offlining memory David Hildenbrand
2019-10-14 9:39 ` David Hildenbrand
2019-10-14 19:16 ` Andrew Morton
2019-10-27 22:45 ` David Hildenbrand
2019-11-30 23:21 ` Andrew Morton
2019-11-30 23:43 ` David Hildenbrand
2019-12-18 17:08 ` David Hildenbrand [this message]
2019-12-18 20:16 ` Andrew Morton
2019-12-03 15:10 ` Oscar Salvador
2019-12-03 15:27 ` David Hildenbrand
2019-10-06 8:56 ` [PATCH v6 06/10] mm/memory_hotplug: Poison memmap in remove_pfn_range_from_zone() David Hildenbrand
2019-10-16 14:01 ` David Hildenbrand
2020-02-04 8:59 ` Oscar Salvador
2019-10-06 8:56 ` [PATCH v6 07/10] mm/memory_hotplug: We always have a zone in find_(smallest|biggest)_section_pfn David Hildenbrand
2020-02-04 9:06 ` Oscar Salvador
2020-02-05 8:57 ` Wei Yang
2020-02-05 8:59 ` David Hildenbrand
2020-02-05 9:26 ` Wei Yang
2019-10-06 8:56 ` [PATCH v6 08/10] mm/memory_hotplug: Don't check for "all holes" in shrink_zone_span() David Hildenbrand
2020-02-04 9:13 ` Oscar Salvador
2020-02-04 9:20 ` David Hildenbrand
2020-02-04 14:25 ` Baoquan He
2020-02-04 14:42 ` David Hildenbrand
2020-02-05 12:43 ` Baoquan He
2020-02-05 13:20 ` David Hildenbrand
2020-02-05 13:34 ` Baoquan He
2020-02-05 13:38 ` David Hildenbrand
2020-02-05 14:12 ` Baoquan He
2020-02-05 14:16 ` David Hildenbrand
2020-02-05 14:26 ` Baoquan He
2020-02-05 9:59 ` Wei Yang
2020-02-05 14:48 ` Baoquan He
2020-02-05 22:56 ` Wei Yang
2020-02-05 23:08 ` Baoquan He
2020-02-05 23:26 ` Wei Yang
2020-02-05 23:30 ` Baoquan He
2020-02-05 23:34 ` Wei Yang
2020-02-05 14:54 ` David Laight
2020-02-05 14:55 ` David Hildenbrand
2019-10-06 8:56 ` [PATCH v6 09/10] mm/memory_hotplug: Drop local variables " David Hildenbrand
2020-02-04 9:26 ` Oscar Salvador
2020-02-04 9:29 ` David Hildenbrand
2020-02-05 10:07 ` Wei Yang
2019-10-06 8:56 ` [PATCH v6 10/10] mm/memory_hotplug: Cleanup __remove_pages() David Hildenbrand
2020-02-04 9:46 ` Oscar Salvador
2020-02-04 12:41 ` David Hildenbrand
2020-02-04 13:13 ` Segher Boessenkool
2020-02-04 13:38 ` David Hildenbrand
2020-02-05 12:51 ` Segher Boessenkool
2020-02-05 13:17 ` David Hildenbrand
2020-02-05 13:18 ` David Hildenbrand
2020-02-05 13:23 ` David Hildenbrand
2020-02-05 11:48 ` Wei Yang
2019-12-02 9:09 ` [PATCH v6 00/10] mm/memory_hotplug: Shrink zones before removing memory David Hildenbrand
2019-12-03 13:36 ` Oscar Salvador
2020-01-31 4:40 ` Andrew Morton
2020-01-31 9:18 ` David Hildenbrand
2020-01-31 10:03 ` Michal Hocko
2020-01-31 10:36 ` David Hildenbrand
2020-02-04 1:46 ` Andrew Morton
2020-02-04 8:45 ` David Hildenbrand
2020-02-04 9:51 ` Oscar Salvador
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