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X-CSE-ConnectionGUID: hEhjcD/hQ4WEopfExoQkLA== X-CSE-MsgGUID: SXGYu5ZiRDeuBGUW24eAVg== X-IronPort-AV: E=McAfee;i="6800,10657,11686"; a="74659848" X-IronPort-AV: E=Sophos;i="6.21,263,1763452800"; d="scan'208";a="74659848" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jan 2026 07:09:11 -0800 X-CSE-ConnectionGUID: AdpxE0LwSkGuKfBxrwrP3Q== X-CSE-MsgGUID: FC6X6yZ7QyuuUFA60B2CoQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,263,1763452800"; d="scan'208";a="212950008" Received: from linux-pnp-server-27.sh.intel.com ([10.239.147.41]) by orviesa003.jf.intel.com with ESMTP; 30 Jan 2026 07:09:07 -0800 From: Tianyou Li To: David Hildenbrand , Oscar Salvador , Mike Rapoport , Wei Yang , Michal Hocko Cc: linux-mm@kvack.org, Yong Hu , Nanhai Zou , Yuan Liu , Tim Chen , Qiuxu Zhuo , Yu C Chen , Pan Deng , Tianyou Li , Chen Zhang , linux-kernel@vger.kernel.org Subject: [PATCH] mm/memory hotplug: Fix zone->contiguous always false when hotplug Date: Sat, 31 Jan 2026 00:09:38 +0800 Message-ID: <20260130160938.2671462-1-tianyou.li@intel.com> X-Mailer: git-send-email 2.47.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 623AD40007 X-Stat-Signature: frcg3boncnm1e35hhssju7o88ssqfcm7 X-Rspam-User: X-HE-Tag: 1769785752-838976 X-HE-Meta: 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 q0zeAhJ9 K/N8EBzj5/++BP+7A9DBJ5WboC0RHXUiIJVb3lUuLQJzmHAHqxBhlJ3e8dS62mZSa/zg9NmOgpUE9Pv20auCjYrWA6A8jGvzg5WwPqU9tiUEuGYbcU0SHf79dbN/HQMccjN7Y2dQYDURyEaAppf5QjyROXJKGuBO+a2ptP4/IMO1MpbR99JHWPfrg5MNfSd8nmdfCS1LQOD7PShUEsJVLl+zOZFbCVenYQCKyGaGxlrElh/MSe7XpLBMyeYH3csXwEkB+tPeohnKN1zaIF6HBLVxwCJb31nu6Kp+Ygq9KrKXLsiqP/UjDyK53AZnAPlxWX+GNJF7+swtxK3M= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Yuan Liu set_zone_contiguous() uses __pageblock_pfn_to_page() to detect pageblocks that either do not exist (hole) or that do not belong to the same zone. __pageblock_pfn_to_page(), however, relies on pfn_to_online_page(), effectively always returning NULL for memory ranges that were not onlined yet. So when called on a range-to-be-onlined, it indicates a memory hole to set_zone_contiguous(). Consequently, the set_zone_contiguous() call in move_pfn_range_to_zone(), which happens early during memory onlining, will never detect a zone as being contiguous. Bad: the fast path relies on the zone contiguous state may skipped. To fix the issue, move the set_zone_contiguous() call to a later stage in memory onlining, where pfn_to_online_page() will succeed: after we mark the memory sections to be online. Fixes: 2d070eab2e82 ("mm: consider zone which is not fully populated to have holes") Cc: Michal Hocko Cc: stable@vger.kernel.org Reviewed-by: Nanhai Zou Signed-off-by: Yuan Liu Signed-off-by: Tianyou Li --- Separated from: https://lore.kernel.org/linux-mm/20260120143346.1427837-1-tianyou.li@intel.com/ mm/memory_hotplug.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index a63ec679d861..c8f492b5daf0 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -782,8 +782,6 @@ void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn, memmap_init_range(nr_pages, nid, zone_idx(zone), start_pfn, 0, MEMINIT_HOTPLUG, altmap, migratetype, isolate_pageblock); - - set_zone_contiguous(zone); } struct auto_movable_stats { @@ -1205,6 +1203,13 @@ int online_pages(unsigned long pfn, unsigned long nr_pages, } online_pages_range(pfn, nr_pages); + + /* + * Now that the ranges are indicated as online, check whether the whole + * zone is contiguous. + */ + set_zone_contiguous(zone); + adjust_present_page_count(pfn_to_page(pfn), group, nr_pages); if (node_arg.nid >= 0) -- 2.47.1