From: Dan Williams <dan.j.williams@intel.com>
To: linux-mm@kvack.org
Cc: David Hildenbrand <david@redhat.com>,
stable@vger.kernel.org, Naoya Horiguchi <nao.horiguchi@gmail.com>,
Qian Cai <cai@lca.pw>, Michal Hocko <mhocko@kernel.org>,
Oscar Salvador <osalvador@suse.de>,
Michal Hocko <mhocko@suse.com>,
Naoya Horiguchi <naoya.horiguchi@nec.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3 0/6] mm: Fix pfn_to_online_page() with respect to ZONE_DEVICE
Date: Tue, 12 Jan 2021 23:35:15 -0800 [thread overview]
Message-ID: <161052331545.1805594.2356512831689786960.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
Changes since v2 [1]:
- Collect some reviewed-by's from David and Oscar
- Rework subsection validity to include pfn_valid() gated by
CONFIG_HAVE_ARCH_PFN_VALID (David, Oscar)
- Introduce pgmap_pfn_valid() to validate metadata vs data in a pgmap (David)
! Kill put_ref_page(): the extra "if (ref_page) put_page(ref_page)" still
feels more cluttered than adding a tiny helper. (Oscar)
[1]: http://lore.kernel.org/r/161044407603.1482714.16630477578392768273.stgit@dwillia2-desk3.amr.corp.intel.com
---
Michal reminds that the discussion about how to ensure pfn-walkers do
not get confused by ZONE_DEVICE pages never resolved. A pfn-walker that
uses pfn_to_online_page() may inadvertently translate a pfn as online
and in the page allocator, when it is offline managed by a ZONE_DEVICE
mapping (details in Patch 3: ("mm: Teach pfn_to_online_page() about
ZONE_DEVICE section collisions")).
The 2 proposals under consideration are teach pfn_to_online_page() to be
precise in the presence of mixed-zone sections, or teach the memory-add
code to drop the System RAM associated with ZONE_DEVICE collisions. In
order to not regress memory capacity by a few 10s to 100s of MiB the
approach taken in this set is to add precision to pfn_to_online_page().
In the course of validating pfn_to_online_page() a couple other fixes
fell out:
1/ soft_offline_page() fails to drop the reference taken in the
madvise(..., MADV_SOFT_OFFLINE) case.
2/ The libnvdimm sysfs attribute visibility code was failing to publish
the resource base for memmap=ss!nn defined namespaces. This is needed
for the regression test for soft_offline_page().
3/ memory_failure() uses get_dev_pagemap() to lookup ZONE_DEVICE pages,
however that mapping may contain data pages and metadata raw pfns.
Introduce pgmap_pfn_valid() to delineate the 2 types and fail the
handling of raw metadata pfns.
---
Dan Williams (6):
mm: Move pfn_to_online_page() out of line
mm: Teach pfn_to_online_page() to consider subsection validity
mm: Teach pfn_to_online_page() about ZONE_DEVICE section collisions
mm: Fix page reference leak in soft_offline_page()
mm: Fix memory_failure() handling of dax-namespace metadata
libnvdimm/namespace: Fix visibility of namespace resource attribute
drivers/nvdimm/namespace_devs.c | 10 +++---
include/linux/memory_hotplug.h | 17 +--------
include/linux/memremap.h | 6 +++
include/linux/mmzone.h | 22 ++++++++----
mm/memory-failure.c | 26 ++++++++++++--
mm/memory_hotplug.c | 70 +++++++++++++++++++++++++++++++++++++++
mm/memremap.c | 15 ++++++++
7 files changed, 134 insertions(+), 32 deletions(-)
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next reply other threads:[~2021-01-13 7:35 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-13 7:35 Dan Williams [this message]
2021-01-13 7:35 ` [PATCH v3 1/6] mm: Move pfn_to_online_page() out of line Dan Williams
2021-01-13 7:35 ` [PATCH v3 2/6] mm: Teach pfn_to_online_page() to consider subsection validity Dan Williams
2021-01-13 8:29 ` David Hildenbrand
2021-01-13 21:52 ` Dan Williams
2021-01-13 8:30 ` Oscar Salvador
2021-01-13 7:35 ` [PATCH v3 3/6] mm: Teach pfn_to_online_page() about ZONE_DEVICE section collisions Dan Williams
2021-01-13 7:35 ` [PATCH v3 4/6] mm: Fix page reference leak in soft_offline_page() Dan Williams
2021-01-13 7:35 ` [PATCH v3 5/6] mm: Fix memory_failure() handling of dax-namespace metadata Dan Williams
2021-01-13 8:31 ` David Hildenbrand
2021-01-13 7:35 ` [PATCH v3 6/6] libnvdimm/namespace: Fix visibility of namespace resource attribute Dan Williams
2021-01-13 8:35 ` Greg KH
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