From: Daniel Jordan <daniel.m.jordan@oracle.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
David Hildenbrand <david@redhat.com>,
Michal Hocko <mhocko@kernel.org>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Peter Zijlstra <peterz@infradead.org>,
Steven Sistare <steven.sistare@oracle.com>
Subject: Re: [PATCH v2] x86/mm: use max memory block size on bare metal
Date: Thu, 11 Jun 2020 23:29:59 -0400 [thread overview]
Message-ID: <20200612032959.yo43ydg273zu35lx@ca-dmjordan1.us.oracle.com> (raw)
In-Reply-To: <adcd3359-a90b-ab62-60e1-102277533e11@intel.com>
On Thu, Jun 11, 2020 at 10:05:38AM -0700, Dave Hansen wrote:
> One other nit for this. We *do* have actual hardware hotplug, and I'm
> pretty sure the alignment guarantees for hardware hotplug are pretty
> weak. For instance, the alignment guarantees for persistent memory are
> still only 64MB even on modern platforms.
>
> Let's say we're on bare metal and we see an SRAT table that has some
> areas that show that hotplug might happen there. Is this patch still
> ideal there?
Well, not if there's concern about hardware hotplug.
My assumption going in was that this wasn't a problem in practice.
078eb6aa50dc50 ("x86/mm/memory_hotplug: determine block size based on the end
of boot memory") was merged in 2018 to address qemu hotplug failures and >64G
systems have used a 2G block since 2014 with no complaints about alignment
issues, to my knowledge anyway.
next prev parent reply other threads:[~2020-06-12 3:29 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-09 22:54 Daniel Jordan
2020-06-09 23:03 ` Daniel Jordan
2020-06-10 7:20 ` David Hildenbrand
2020-06-10 7:30 ` David Hildenbrand
2020-06-10 17:16 ` Daniel Jordan
2020-06-11 14:16 ` Dave Hansen
2020-06-11 16:59 ` Daniel Jordan
2020-06-11 17:05 ` Dave Hansen
2020-06-12 3:29 ` Daniel Jordan [this message]
2020-06-19 12:07 ` Michal Hocko
2020-06-22 19:17 ` Daniel Jordan
2020-06-26 12:47 ` Michal Hocko
2020-07-08 18:46 ` Daniel Jordan
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