Messages in this thread | | | Date | Thu, 11 Jun 2020 23:29:59 -0400 | From | Daniel Jordan <> | Subject | Re: [PATCH v2] x86/mm: use max memory block size on bare metal |
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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.
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