From: "Verma, Vishal L" <vishal.l.verma@intel.com>
To: "mhocko@kernel.org" <mhocko@kernel.org>
Cc: "Williams, Dan J" <dan.j.williams@intel.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
"david@redhat.com" <david@redhat.com>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>
Subject: Re: [PATCH v3] mm/memory_hotplug: refrain from adding memory into an impossible node
Date: Wed, 15 Apr 2020 20:32:00 +0000 [thread overview]
Message-ID: <7a37b7c03e983ceb32337325fa2a724fa614607b.camel@intel.com> (raw)
In-Reply-To: <20200415104338.GF4629@dhcp22.suse.cz>
On Wed, 2020-04-15 at 12:43 +0200, Michal Hocko wrote:
> On Tue 14-04-20 17:58:12, Vishal Verma wrote:
> [...]
> > +static int check_hotplug_node(int nid)
> > +{
> > + int alt_nid;
> > +
> > + if (node_possible(nid))
> > + return nid;
> > +
> > + alt_nid = numa_map_to_online_node(nid);
> > + if (alt_nid == NUMA_NO_NODE)
> > + alt_nid = first_online_node;
> > + WARN_TAINT(1, TAINT_FIRMWARE_WORKAROUND,
> > + "node %d expected, but was absent from the node_possible_map, using %d instead\n",
> > + nid, alt_nid);
>
> I really do not like this. Why should we try to be clever and change the
> node id requested by the caller? I would just stick with node_possible
> check and be done with this.
Hi Michal,
Being clever allows us to still use the memory even if it is in a non-
optimal configuration. Failing here leaves the user no path to add this
memory until the firmware is fixed. It is the tradeoff between some
usability vs. how loud we want to be for the failure.
next prev parent reply other threads:[~2020-04-15 20:32 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-14 23:58 [PATCH v3] mm/memory_hotplug: refrain from adding memory into an impossible node Vishal Verma
2020-04-15 7:39 ` David Hildenbrand
2020-04-15 7:44 ` David Hildenbrand
2020-04-15 10:43 ` Michal Hocko
2020-04-15 20:32 ` Verma, Vishal L [this message]
2020-04-16 6:19 ` Michal Hocko
2020-04-16 16:13 ` Verma, Vishal L
2020-04-16 16:16 ` David Hildenbrand
2020-04-16 16:18 ` Verma, Vishal L
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