linux-kernel - Re: [PATCH] drivers/base/memory: Avoid overhead from for_each_present_section

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Message-ID: <Z_fNx7hTOR8St0SM@localhost.localdomain>
Date: Thu, 10 Apr 2025 15:55:19 +0200
From: Oscar Salvador <osalvador@...e.de>
To: David Hildenbrand <david@...hat.com>
Cc: Gavin Shan <gshan@...hat.com>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, adityag@...ux.ibm.com,
	donettom@...ux.ibm.com, gregkh@...uxfoundation.org,
	rafael@...nel.org, dakr@...nel.org, akpm@...ux-foundation.org,
	shan.gavin@...il.com
Subject: Re: [PATCH] drivers/base/memory: Avoid overhead from
 for_each_present_section_nr()

On Thu, Apr 10, 2025 at 03:18:00PM +0200, David Hildenbrand wrote:
> Staring at the end result and the particularly long comment, are we now
> really any better than before 61659efdb35c?

I think we are.
I mean, we made it slightly worse with 61659efdb35c because of what I
explained in the error report, but I think this version is faster than
the code before 61659efdb35c, as before that the outter loop was
incremented by 1 any given time, meaning that the section we were passing
to add_boot_memory_block() could have been already checked in there for
memory-blocks spanning multiple sections.

All in all, I think we are better, and the code is slightly simpler?

-- 
Oscar Salvador
SUSE Labs