From: David Hildenbrand <david@redhat.com>
To: Anshuman Khandual <anshuman.khandual@arm.com>,
linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org
Cc: akpm@linux-foundation.org, catalin.marinas@arm.com,
mark.rutland@arm.com, Michal Hocko <mhocko@suse.com>,
Dan Williams <dan.j.williams@intel.com>,
Yu Zhao <yuzhao@google.com>, Hsin-Yi Wang <hsinyi@chromium.org>,
Thomas Gleixner <tglx@linutronix.de>,
Steve Capper <steve.capper@arm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] arm64/hotplug: Process MEM_OFFLINE and MEM_CANCEL_OFFLINE events
Date: Wed, 15 Apr 2020 09:35:33 +0200 [thread overview]
Message-ID: <31ce355b-abf7-ac3b-a5b4-ae1b0a52fb3c@redhat.com> (raw)
In-Reply-To: <1586932784-16315-1-git-send-email-anshuman.khandual@arm.com>
On 15.04.20 08:39, Anshuman Khandual wrote:
> This series improves arm64 memory event notifier (hot remove) robustness by
> enabling it to detect potential problems (if any) in the future. But first
> it enumerates memory isolation failure reasons that can be sent across a
> notifier. This series does not go beyond arm64 to explore if these failure
> reason codes could be used in other existing registered memory notifiers.
> Please do let me know if there is any other potential use cases, will be
> happy to incorporate next time around. Also should we add similar failure
> reasons for online_pages() as well ?
>
> This series has been tested on arm64, boot tested on x86 and build tested
> on multiple other platforms.
>
I'm sorry, but I have to nack this series. Why?
1. A hotplug notifier should not have to bother why offlining failed. He
received a MEM_GOING_OFFLINE, followed by a MEM_CANCEL_OFFLINE. That's
all he really has to know. Undo what you've done, end of story.
2. Patch 2 just introduces dead code that should never happen unless
something is horribly broken in the core (memory offlined although
nacked from notifier). And, it (for *whatever reason*) thinks it's okay
to bail out if another notifier canceled offlining hotplugged memory.
I fail to see the benefit for core changes and
4 files changed, 99 insertions(+), 13 deletions(-)
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2020-04-15 7:35 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-15 6:39 [PATCH 0/2] arm64/hotplug: Process MEM_OFFLINE and MEM_CANCEL_OFFLINE events Anshuman Khandual
2020-04-15 6:39 ` [PATCH 1/2] mm/hotplug: Enumerate memory range offlining failure reasons Anshuman Khandual
2020-04-15 6:39 ` [PATCH 2/2] arm64/hotplug: Process MEM_OFFLINE and MEM_CANCEL_OFFLINE Anshuman Khandual
2020-04-15 7:35 ` David Hildenbrand [this message]
2020-04-15 10:16 ` [PATCH 0/2] arm64/hotplug: Process MEM_OFFLINE and MEM_CANCEL_OFFLINE events Michal Hocko
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