From: Mike Rapoport <rppt@kernel.org>
To: Yuan Liu <yuan1.liu@intel.com>
Cc: David Hildenbrand <david@kernel.org>,
Oscar Salvador <osalvador@suse.de>,
Wei Yang <richard.weiyang@gmail.com>,
linux-mm@kvack.org, Nanhai Zou <nanhai.zou@intel.com>,
Chen Zhang <zhangchen.kidd@jd.com>,
Jason Zeng <jason.zeng@intel.com>, Chen Yu <yu.c.chen@intel.com>,
Pan Deng <pan.deng@intel.com>, Tianyou Li <tianyou.li@intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 2/2] mm/memory_hotplug: optimize zone contiguous check when changing pfn range
Date: Wed, 19 Aug 2026 17:56:04 +0300 [thread overview]
Message-ID: <aoXEBCWQ-a9OB_YE@kernel.org> (raw)
In-Reply-To: <20260818085702.3395529-3-yuan1.liu@intel.com>
On Tue, Aug 18, 2026 at 04:57:02AM -0400, Yuan Liu wrote:
> When move_pfn_range_to_zone() or remove_pfn_range_from_zone() updates a
> zone, set_zone_contiguous() rescans the entire zone pageblock-by-pageblock
> to rebuild zone->contiguous. For large zones this is a significant cost
> during memory hotplug and hot-unplug.
>
> Add a new zone member, pages_with_online_memmap, that tracks the
> number of pages within the zone span that have an online memory map,
> including present pages and memory holes whose memory map has been
> initialized and for which pfn_to_online_page() succeeds.
>
> For early boot memory, pages_with_online_memmap is calculated in
> memmap_init_zone_range(). PFNs initialized by memmap_init_range() are
> included in pages_with_online_memmap, and hole PFNs for which
> pfn_to_online_page() succeeds are also counted in
> init_unavailable_range().
In what scenario it is possible that pfn_to_online_page() would fail at
that point?
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2026-08-19 14:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-18 8:57 [PATCH v7 0/2] mm/memory_hotplug: optimize zone contiguous check when changing pfn range Yuan Liu
2026-08-18 8:57 ` [PATCH v7 1/2] mm/memory_hotplug: make shrink_zone_span() more robust Yuan Liu
2026-08-18 8:57 ` [PATCH v7 2/2] mm/memory_hotplug: optimize zone contiguous check when changing pfn range Yuan Liu
2026-08-19 14:56 ` Mike Rapoport [this message]
2026-08-19 15:43 ` David Hildenbrand (Arm)
2026-08-19 15:53 ` David Hildenbrand (Arm)
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