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From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>,
	Michal Hocko <mhocko@suse.com>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Pavel Tatashin <pasha.tatashin@soleen.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>
Subject: Memory hotplug locking issue: Useless (?) zone span seqlock
Date: Fri, 7 Mar 2025 15:22:26 -0500	[thread overview]
Message-ID: <b3acfb1e-2d7a-42ef-9705-bf0b20a0d152@efficios.com> (raw)

I'm currently perfecting my understanding of the mm code and reviewing
pieces of it as I go, and stumbled on this:

commit 27cacaad16c5 ("mm,memory_hotplug: drop unneeded locking")

This commit removes all users of zone_span_writelock(), thus making
the inline useless, but leaves the now useless
zone_span_seqbegin()/zone_span_seqretry() in place within
page_outside_zone_boundaries().

So I'm confused. What's going on ?

And if this commit got things very wrong when removing the
seqlock, I wonder if there are cases where its partial
pgdat_resize_lock() removal can be an issue as well.

Thanks,

Mathieu

-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com



             reply	other threads:[~2025-03-07 20:22 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-07 20:22 Mathieu Desnoyers [this message]
2025-05-08 10:45 ` David Hildenbrand
2025-05-08 13:11   ` Mathieu Desnoyers
2025-05-09  9:38     ` David Hildenbrand

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