From: Rob Herring <robh@kernel.org>
To: Gavin Shan <gshan@redhat.com>
Cc: devicetree@vger.kernel.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-efi <linux-efi@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
"open list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)"
<kvmarm@lists.cs.columbia.edu>, Marc Zyngier <maz@kernel.org>,
Randy Dunlap <rdunlap@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
shan.gavin@gmail.com
Subject: Re: [PATCH v2 2/2] of, numa: Fetch empty NUMA node ID from distance map
Date: Tue, 28 Sep 2021 12:22:08 -0500 [thread overview]
Message-ID: <CAL_JsqJtckde=Ngfhr7u3f_xsccavo+4Pt-v9o_nGHTX+wD91w@mail.gmail.com> (raw)
In-Reply-To: <c101363f-1de7-1d56-a8d9-243f003b48c1@redhat.com>
On Mon, Sep 27, 2021 at 6:59 PM Gavin Shan <gshan@redhat.com> wrote:
>
> Hi Rob,
>
> On 9/28/21 12:49 AM, Rob Herring wrote:
> > On Mon, Sep 27, 2021 at 1:42 AM Gavin Shan <gshan@redhat.com> wrote:
> >>
> >> There is no device node for the empty NUMA node. However, the
> >> corresponding NUMA node ID and distance map is still valid in
> >> "numa-distance-map-v1" compatible device node.
> >>
> >> This fetches the NUMA node ID and distance map for these empty
> >> NUMA node from "numa-distance-map-v1" compatible device node.
> >
> > This is much nicer.
> >
>
> Indeed, thanks for your suggestions :)
>
> >> Signed-off-by: Gavin Shan <gshan@redhat.com>
> >> ---
> >> drivers/of/of_numa.c | 2 ++
> >> 1 file changed, 2 insertions(+)
> >>
> >> diff --git a/drivers/of/of_numa.c b/drivers/of/of_numa.c
> >> index fe6b13608e51..5949829a1b00 100644
> >> --- a/drivers/of/of_numa.c
> >> +++ b/drivers/of/of_numa.c
> >> @@ -111,6 +111,8 @@ static int __init of_numa_parse_distance_map_v1(struct device_node *map)
> >> return -EINVAL;
> >> }
> >>
> >> + node_set(nodea, numa_nodes_parsed);
> >> +
> >
> > With this, couldn't we remove of_numa_parse_cpu_nodes() as the only
> > thing it does is node_set()?
> >
>
> I don't think so for couple of reasons:
>
> (1) With problematic device-tree, the distance map node might be missed
> or incomplete. In this case, of_numa_parse_cpu_nodes() still helps.
It's not the kernel's job to validate the DT (if it was, it is doing a
terrible job). I would suggest writing some checks for dtc if we're
worried about correctness. (The schemas don't work too well for cross
node checks.)
> (2) @numa_nodes_parsed is also updated when the memory nodes are iterated
> in of_numa_parse_memory_nodes() and numa_add_memblk().
>
> So @numa_nodes_parsed, which is synchronized to @node_possible_map afterwards,
> is the gathering output of CPU nodes, memory nodes and distance map node.
Is it valid to have node id's that are not in the distance map?
Rob
next prev parent reply other threads:[~2021-09-28 17:22 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-27 6:41 [PATCH v2 0/2] Specify empty NUMA node Gavin Shan
2021-09-27 6:41 ` [PATCH v2 1/2] Documentation, dt, numa: Add note to " Gavin Shan
2021-10-04 18:13 ` Rob Herring
2021-09-27 6:41 ` [PATCH v2 2/2] of, numa: Fetch empty NUMA node ID from distance map Gavin Shan
2021-09-27 14:49 ` Rob Herring
2021-09-27 23:59 ` Gavin Shan
2021-09-28 17:22 ` Rob Herring [this message]
2021-09-29 2:00 ` Gavin Shan
2021-10-04 18:13 ` Rob Herring
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