From: David Hildenbrand <david@redhat.com>
To: Jia He <justin.he@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>
Cc: Kaly Xin <Kaly.Xin@arm.com>, Michal Hocko <mhocko@suse.com>,
Baoquan He <bhe@redhat.com>,
linux-nvdimm@lists.01.org, Chuhong Yuan <hslester96@gmail.com>,
linux-kernel@vger.kernel.org, Mike Rapoport <rppt@linux.ibm.com>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH v2 2/3] device-dax: use fallback nid when numa_node is invalid
Date: Tue, 7 Jul 2020 13:34:12 +0200 [thread overview]
Message-ID: <2409a5d4-e77b-f570-c788-feb4f6ebb498@redhat.com> (raw)
In-Reply-To: <20200707055917.143653-3-justin.he@arm.com>
On 07.07.20 07:59, Jia He wrote:
> Previously, numa_off is set unconditionally at the end of dummy_numa_init(),
> even with a fake numa node. Then ACPI detects node id as NUMA_NO_NODE(-1) in
> acpi_map_pxm_to_node() because it regards numa_off as turning off the numa
> node. Hence dev_dax->target_node is NUMA_NO_NODE on arm64 with fake numa.
>
> Without this patch, pmem can't be probed as a RAM device on arm64 if SRAT table
> isn't present:
> $ndctl create-namespace -fe namespace0.0 --mode=devdax --map=dev -s 1g -a 64K
> kmem dax0.0: rejecting DAX region [mem 0x240400000-0x2bfffffff] with invalid node: -1
> kmem: probe of dax0.0 failed with error -22
>
> This fixes it by using fallback memory_add_physaddr_to_nid() as nid.
>
> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Jia He <justin.he@arm.com>
> ---
> I noticed that on powerpc memory_add_physaddr_to_nid is not exported for module
> driver. Set it to RFC due to this concern.
>
> drivers/dax/kmem.c | 22 ++++++++++++++--------
> 1 file changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
> index 275aa5f87399..68e693ca6d59 100644
> --- a/drivers/dax/kmem.c
> +++ b/drivers/dax/kmem.c
> @@ -28,20 +28,22 @@ int dev_dax_kmem_probe(struct device *dev)
> resource_size_t kmem_end;
> struct resource *new_res;
> const char *new_res_name;
> - int numa_node;
> + int numa_node, new_node;
> int rc;
>
> /*
> * Ensure good NUMA information for the persistent memory.
> - * Without this check, there is a risk that slow memory
> - * could be mixed in a node with faster memory, causing
> - * unavoidable performance issues.
> + * Without this check, there is a risk but not fatal that slow
> + * memory could be mixed in a node with faster memory, causing
> + * unavoidable performance issues. Furthermore, fallback node
> + * id can be used when numa_node is invalid.
> */
> numa_node = dev_dax->target_node;
> if (numa_node < 0) {
> - dev_warn(dev, "rejecting DAX region %pR with invalid node: %d\n",
> - res, numa_node);
> - return -EINVAL;
> + new_node = memory_add_physaddr_to_nid(kmem_start);
> + dev_info(dev, "changing nid from %d to %d for DAX region %pR\n",
> + numa_node, new_node, res);
> + numa_node = new_node;
Now, the warning does not really make sense. We have NUMA_NO_NODE (< 0),
that is not a change in the nid, but a selection of a nid. Printing
NUMA_NO_NODE does not make too much sense. I suggest just getting rid of
new_node and turning the dev_info() into something like
dev_info(dev, "using nid %d for DAX region with undefined nid %pR\n",
numa_node, res);
--
Thanks,
David / dhildenb
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next prev parent reply other threads:[~2020-07-07 11:35 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 5:59 [PATCH v2 0/3] Fix and enable pmem as RAM device on arm64 Jia He
2020-07-07 5:59 ` [PATCH v2 1/3] arm64/numa: export memory_add_physaddr_to_nid as EXPORT_SYMBOL_GPL Jia He
2020-07-07 11:35 ` David Hildenbrand
2020-07-07 11:54 ` Michal Hocko
2020-07-07 12:13 ` Mike Rapoport
2020-07-07 12:26 ` David Hildenbrand
2020-07-07 18:00 ` Mike Rapoport
2020-07-07 22:05 ` Dan Williams
2020-07-08 5:27 ` Mike Rapoport
2020-07-08 7:21 ` David Hildenbrand
2020-07-08 7:38 ` Mike Rapoport
2020-07-08 7:40 ` David Hildenbrand
2020-07-08 7:50 ` Dan Williams
2020-07-08 8:26 ` David Hildenbrand
2020-07-08 8:39 ` Mike Rapoport
2020-07-08 8:45 ` David Hildenbrand
2020-07-08 9:15 ` Mike Rapoport
2020-07-08 9:25 ` David Hildenbrand
2020-07-08 9:45 ` Mike Rapoport
2020-07-08 10:04 ` David Hildenbrand
2020-07-08 15:50 ` Dan Williams
2020-07-08 16:10 ` David Hildenbrand
2020-07-08 16:47 ` Mike Rapoport
2020-07-08 2:20 ` Justin He
2020-07-08 3:56 ` Dan Williams
2020-07-08 4:08 ` Justin He
2020-07-08 4:27 ` Dan Williams
2020-07-08 6:22 ` Mike Rapoport
2020-07-08 6:53 ` Dan Williams
2020-07-08 6:59 ` David Hildenbrand
2020-07-08 7:04 ` Dan Williams
2020-07-08 7:16 ` David Hildenbrand
2020-07-08 7:43 ` Mike Rapoport
2020-07-08 5:32 ` Mike Rapoport
2020-07-08 5:48 ` Dan Williams
2020-07-08 6:19 ` Mike Rapoport
2020-07-08 6:44 ` Dan Williams
2020-07-08 6:56 ` Justin He
2020-07-08 7:00 ` David Hildenbrand
2020-07-07 5:59 ` [RFC PATCH v2 2/3] device-dax: use fallback nid when numa_node is invalid Jia He
2020-07-07 6:08 ` Justin He
2020-07-07 11:34 ` David Hildenbrand [this message]
2020-07-08 1:41 ` Justin He
2020-07-07 5:59 ` [PATCH v2 3/3] mm/memory_hotplug: fix unpaired mem_hotplug_begin/done Jia He
2020-07-07 10:06 ` Michal Hocko
2020-07-07 11:31 ` David Hildenbrand
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