From: Andrew Morton <akpm@linux-foundation.org>
To: David Hildenbrand <david@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Rich Felker <dalias@libc.org>,
linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Wei Yang <richard.weiyang@gmail.com>,
linux-mm@kvack.org, Michal Hocko <mhocko@suse.com>,
Paul Mackerras <paulus@samba.org>,
"H. Peter Anvin" <hpa@zytor.com>, Will Deacon <will@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
linux-s390@vger.kernel.org, Yu Zhao <yuzhao@google.com>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Halil Pasic <pasic@linux.ibm.com>, Jason Gunthorpe <jgg@ziepe.ca>,
x86@kernel.org, "Matthew Wilcox \(Oracle\)" <willy@infradead.org>,
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Ira Weiny <ira.weiny@intel.com>,
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Masahiro Yamada <yamada.masahiro@socionext.com>,
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Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org,
Oscar Salvador <osalvador@suse.de>,
Tony Luck <tony.luck@intel.com>,
Steve Capper <steve.capper@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
linux-kernel@vger.kernel.org,
Logan Gunthorpe <logang@deltatee.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Qian Cai <cai@lca.pw>, Tom Lendacky <thomas.lendacky@amd.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v6 05/10] mm/memory_hotplug: Shrink zones when offlining memory
Date: Wed, 18 Dec 2019 12:16:04 -0800 [thread overview]
Message-ID: <20191218121604.520927a74bbe65d47669b32a@linux-foundation.org> (raw)
In-Reply-To: <4a3d7420-2d11-a37c-0e82-2096fbf7bca6@redhat.com>
On Wed, 18 Dec 2019 18:08:04 +0100 David Hildenbrand <david@redhat.com> wrote:
> 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)
Sure, I queued it for the next batch of 5.5 fixes.
next prev parent reply other threads:[~2019-12-18 20:18 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
2019-12-18 20:16 ` Andrew Morton [this message]
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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