From: Matthew Wilcox <willy@infradead.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>,
Dave Hansen <dave.hansen@linux.intel.com>,
Arnd Bergmann <arnd@arndb.de>, Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Roman Gushchin <roman.gushchin@linux.dev>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>,
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
linux-mm@kvack.org, linux-sh@vger.kernel.org,
linux-kernel@vger.kernel.org,
Randy Dunlap <rdunlap@infradead.org>
Subject: Re: [PATCH] mm/slab: Fix undefined init_cache_node_node() for NUMA and !SMP
Date: Wed, 22 Mar 2023 16:46:46 +0000 [thread overview]
Message-ID: <ZBsw9lRbJU4c2wLD@casper.infradead.org> (raw)
In-Reply-To: <6320abf6-0898-361b-d5f6-bcc58306f55c@intel.com>
On Wed, Mar 22, 2023 at 09:16:55AM -0700, Dave Hansen wrote:
> On 3/21/23 09:40, Matthew Wilcox wrote:
> > On Tue, Mar 21, 2023 at 09:30:59AM +0100, Geert Uytterhoeven wrote:
> >> -#if (defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)) || defined(CONFIG_SMP)
> >> +#if defined(CONFIG_NUMA) || defined(CONFIG_SMP)
> > I'm amused by the thought of CONFIG_NUMA without CONFIG_SMP.
> > Is it possible to have one node with memory and a single CPU, then
> > another node with memory and no CPU?
>
> It's _possible_ for sure, just unlikely. The most likely place these
> days is probably a teensy tiny VM that just happens to have some
> performance-differentiated memory exposed to it for some reason. Maybe
> it's got a slice of slow PMEM or fast High-Bandwidth memory for whatever
> reason.
Right, you can construct such a system, but do we support the CONFIG
options of NUMA enabled and SMP disabled? It seems so niche that we
shouldn't be spending time testing that combination.
next prev parent reply other threads:[~2023-03-22 16:47 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-21 8:30 Geert Uytterhoeven
2023-03-21 8:41 ` John Paul Adrian Glaubitz
2023-03-21 8:50 ` Geert Uytterhoeven
2023-03-21 15:07 ` Vlastimil Babka
2023-03-21 15:29 ` Randy Dunlap
2023-03-21 16:40 ` Matthew Wilcox
2023-03-21 16:43 ` Randy Dunlap
2023-03-22 16:16 ` Dave Hansen
2023-03-22 16:46 ` Matthew Wilcox [this message]
2023-03-22 16:49 ` Dave Hansen
2023-03-23 8:25 ` Geert Uytterhoeven
2023-03-23 8:28 ` John Paul Adrian Glaubitz
2023-03-23 8:36 ` Geert Uytterhoeven
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