linux-kernel - Re: [PATCH v8 0/3] memory,x86,acpi: hotplug memory alignment advisement

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Message-ID: <Z-w2O8O9MGJ1Ok78@localhost.localdomain>
Date: Tue, 1 Apr 2025 20:53:47 +0200
From: Oscar Salvador <osalvador@...e.de>
To: Gregory Price <gourry@...rry.net>
Cc: linux-mm@...ck.org, linux-acpi@...r.kernel.org, kernel-team@...a.com,
	x86@...nel.org, linux-kernel@...r.kernel.org,
	dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
	tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com,
	rafael@...nel.org, lenb@...nel.org, david@...hat.com,
	gregkh@...uxfoundation.org, akpm@...ux-foundation.org,
	dan.j.williams@...el.com, Jonathan.Cameron@...wei.com,
	alison.schofield@...el.com, rrichter@....com, rppt@...nel.org,
	bfaccini@...dia.com, haibo1.xu@...el.com, dave.jiang@...el.com,
	Ira Weiny <ira.weiny@...el.com>, Fan Ni <fan.ni@...sung.com>
Subject: Re: [PATCH v8 0/3] memory,x86,acpi: hotplug memory alignment
 advisement

On Mon, Jan 27, 2025 at 10:34:02AM -0500, Gregory Price wrote:
> v8: nits and tag pickups
> 
> When physical address regions are not aligned to memory block size,
> the misaligned portion is lost (stranded capacity).
> 
> Block size (min/max/selected) is architecture defined. Most architectures
> tend to use the minimum block size or some simplistic heurist. On x86,
> memory block size increases up to 2GB, and is otherwise fitted to the
> alignment of non-hotplug (i.e. not special purpose memory).

I wonder if something like this could help us in improving the
ridiculous situation of having 16MB memory-block size on powerpc.
 

-- 
Oscar Salvador
SUSE Labs