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From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>,
	 David Hildenbrand <david@kernel.org>,
	Lorenzo Stoakes <ljs@kernel.org>,
	 "Liam R. Howlett" <liam@infradead.org>,
	Vlastimil Babka <vbabka@kernel.org>,
	 Mike Rapoport <rppt@kernel.org>,
	Suren Baghdasaryan <surenb@google.com>,
	 Michal Hocko <mhocko@suse.com>, Kairui Song <kasong@tencent.com>,
	 Qi Zheng <qi.zheng@linux.dev>,
	Shakeel Butt <shakeel.butt@linux.dev>,
	 Barry Song <baohua@kernel.org>,
	Axel Rasmussen <axelrasmussen@google.com>,
	 Yuanchu Xie <yuanchu@google.com>, Wei Xu <weixugc@google.com>,
	 Baoquan He <baoquan.he@linux.dev>,
	 Baolin Wang <baolin.wang@linux.alibaba.com>,
	 Brendan Jackman <brendan.jackman@linux.dev>,
	 Johannes Weiner <hannes@cmpxchg.org>, Zi Yan <ziy@nvidia.com>,
	 Jan Kiszka <jan.kiszka@siemens.com>,
	Kieran Bingham <kbingham@kernel.org>,
	 Oscar Salvador <osalvador@suse.de>,
	 Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	 "Rafael J. Wysocki" <rafael@kernel.org>,
	Danilo Krummrich <dakr@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	 linux-cxl@vger.kernel.org, driver-core@lists.linux.dev,
	 linux-fsdevel@vger.kernel.org
Subject: [PATCH v2 03/13] mm/sparse: move initialization of section metadata to sparse_metadata_init()
Date: Mon, 21 Sep 2026 21:58:55 +0200	[thread overview]
Message-ID: <20260921-b4-sparsemem_cleanups-v2-3-54d81d65e125@kernel.org> (raw)
In-Reply-To: <20260921-b4-sparsemem_cleanups-v2-0-54d81d65e125@kernel.org>

Let's move the code responsible for initializing sparse metadata (usemap,
memmap) into a helper. Cleanup the variable while at it (e.g.,
"map_count").

Drop the rather obvious code comments.

No functional change intended.

Acked-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
---
 mm/sparse.c | 43 ++++++++++++++++++++++---------------------
 1 file changed, 22 insertions(+), 21 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index 2b285653abf1e..71288daeb3665 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -255,38 +255,39 @@ static void __init sparse_init_nid(int nid, unsigned long pnum_begin,
 	}
 }
 
+static void __init sparse_metadata_init(void)
+{
+	unsigned long start_section_nr = first_present_section_nr();
+	int nid_begin = sparse_early_nid(__nr_to_section(start_section_nr));
+	unsigned long section_nr, nr_sections = 1;
+
+	for_each_present_section_nr(start_section_nr + 1, section_nr) {
+		const int nid = sparse_early_nid(__nr_to_section(section_nr));
+
+		if (nid == nid_begin) {
+			nr_sections++;
+			continue;
+		}
+		sparse_init_nid(nid_begin, start_section_nr, section_nr, nr_sections);
+		nid_begin = nid;
+		start_section_nr = section_nr;
+		nr_sections = 1;
+	}
+	sparse_init_nid(nid_begin, start_section_nr, section_nr, nr_sections);
+}
+
 /*
  * Allocate the accumulated non-linear sections, allocate a mem_map
  * for each and record the physical to section mapping.
  */
 void __init sparse_init(void)
 {
-	unsigned long pnum_end, pnum_begin, map_count = 1;
-	int nid_begin;
-
 	if (compound_info_has_mask()) {
 		VM_WARN_ON_ONCE(!IS_ALIGNED((unsigned long) pfn_to_page(0),
 				    MAX_FOLIO_VMEMMAP_ALIGN));
 	}
 
-	pnum_begin = first_present_section_nr();
-	nid_begin = sparse_early_nid(__nr_to_section(pnum_begin));
-
-	for_each_present_section_nr(pnum_begin + 1, pnum_end) {
-		int nid = sparse_early_nid(__nr_to_section(pnum_end));
-
-		if (nid == nid_begin) {
-			map_count++;
-			continue;
-		}
-		/* Init node with sections in range [pnum_begin, pnum_end) */
-		sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
-		nid_begin = nid;
-		pnum_begin = pnum_end;
-		map_count = 1;
-	}
-	/* cover the last node */
-	sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
+	sparse_metadata_init();
 	sparse_init_subsection_map();
 	vmemmap_populate_print_last();
 }

-- 
2.43.0


  parent reply	other threads:[~2026-09-21 19:59 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-21 19:58 [PATCH v2 00/13] mm/sparse: remove SECTION_MARKED_PRESENT and further cleanups David Hildenbrand (Arm)
2026-09-21 19:58 ` [PATCH v2 01/13] mm/sparse: move mem_section init to sparse_extreme_init() David Hildenbrand (Arm)
2026-09-21 23:12   ` Zi Yan
2026-09-21 19:58 ` [PATCH v2 02/13] mm/sparse: refactor sparse_sections_init() David Hildenbrand (Arm)
2026-09-21 19:58 ` David Hildenbrand (Arm) [this message]
2026-09-21 19:58 ` [PATCH v2 04/13] mm/sparse: rename and cleanup sparse_init_nid() David Hildenbrand (Arm)
2026-09-21 19:58 ` [PATCH v2 05/13] mm/sparse: cleanup sparse_init_one_section() David Hildenbrand (Arm)
2026-09-21 19:58 ` [PATCH v2 06/13] mm/sparse: rename __highest_present_section_nr to __highest_used_section_nr David Hildenbrand (Arm)
2026-09-21 19:58 ` [PATCH v2 07/13] mm/sparse: remove pfn_in_present_section() David Hildenbrand (Arm)
2026-09-21 19:59 ` [PATCH v2 08/13] mm/sparse: move __highest_used_section_nr handling David Hildenbrand (Arm)
2026-09-22  4:24   ` Oscar Salvador (SUSE)
2026-09-21 19:59 ` [PATCH v2 09/13] scripts/gdb: mm.py: remove fallbacks for SECTION_HAS_MEM_MAP and SECTION_IS_EARLY David Hildenbrand (Arm)
2026-09-21 19:59 ` [PATCH v2 10/13] mm/sparse: remove SECTION_MARKED_PRESENT David Hildenbrand (Arm)
2026-09-21 19:59 ` [PATCH v2 11/13] mm/sparse: remove flags parameter from sparse_init_one_section() David Hildenbrand (Arm)
2026-09-21 19:59 ` [PATCH v2 12/13] fs/proc/page: clarify comment in get_max_dump_pfn() David Hildenbrand (Arm)
2026-09-21 19:59 ` [PATCH v2 13/13] mm/memory_hotplug: drop CONFIG_HAVE_ARCH_PFN_VALID handling from pfn_to_online_page() David Hildenbrand (Arm)
2026-09-22  4:25   ` Oscar Salvador (SUSE)
2026-09-21 22:53 ` [PATCH v2 00/13] mm/sparse: remove SECTION_MARKED_PRESENT and further cleanups Andrew Morton

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