From: David Hildenbrand <david@redhat.com>
To: Dan Williams <dan.j.williams@intel.com>,
Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
stable <stable@vger.kernel.org>,
Vishal Verma <vishal.l.verma@intel.com>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Linux MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm/memory_hotplug: Fix remove_memory() lockdep splat
Date: Fri, 24 Jan 2020 19:13:06 +0100 [thread overview]
Message-ID: <49ad58b4-049e-ba29-8e44-0117d398d284@redhat.com> (raw)
In-Reply-To: <CAPcyv4jcCnfGy5HcYimxcyF6v_Anw4nMdaNHQt4tMrqUaN70Rg@mail.gmail.com>
On 24.01.20 19:04, Dan Williams wrote:
> On Fri, Jan 24, 2020 at 4:56 AM Michal Hocko <mhocko@kernel.org> wrote:
>>
>> On Fri 10-01-20 13:27:24, Dan Williams wrote:
>>> On Fri, Jan 10, 2020 at 9:42 AM David Hildenbrand <david@redhat.com> wrote:
>> [...]
>>>> For your reference (roughly 5 months ago, so not that old)
>>>>
>>>> https://lkml.kernel.org/r/20190724143017.12841-1-david@redhat.com
>>>
>>> Oh, now I see the problem. You need to add that lock so far away from
>>> the __add_memory() to avoid lock inversion problems with the
>>> acpi_scan_lock. The organization I was envisioning would not work
>>> without deeper refactoring.
>>
>> Sorry to come back to this late. Has this been resolved?
>
> The mem_hotplug_lock lockdep splat fix in this patch has not landed.
> David and I have not quite come to consensus on how to resolve online
> racing removal. IIUC David wants that invalidation to be
> pages_correctly_probed(), I would prefer it to be directly tied to the
> object, struct memory_block, that remove_memory_block_devices() has
> modified, mem->section_count = 0.
FWIW, there is no such race possible - esp. zombie devices (see
https://lore.kernel.org/lkml/1580c2bb-5e94-121d-8153-c8a7230b764b@redhat.com/).
(I'm planning to send a patch to remove mem->section_count soon)
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2020-01-24 18:13 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-10 4:30 Dan Williams
2020-01-10 9:10 ` David Hildenbrand
2020-01-10 16:42 ` Dan Williams
2020-01-10 16:54 ` David Hildenbrand
2020-01-10 16:57 ` David Hildenbrand
2020-01-10 17:24 ` Dan Williams
2020-01-10 17:29 ` David Hildenbrand
2020-01-10 17:33 ` Dan Williams
2020-01-10 17:36 ` David Hildenbrand
2020-01-10 17:39 ` Dan Williams
2020-01-10 17:42 ` David Hildenbrand
2020-01-10 21:27 ` Dan Williams
2020-01-24 12:45 ` Michal Hocko
2020-01-24 18:04 ` Dan Williams
2020-01-24 18:13 ` David Hildenbrand [this message]
2020-01-27 13:47 ` Michal Hocko
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