[PATCH 08/12] mm/sparse: move __highest_used_section_nr handling
From: "David Hildenbrand (Arm)" <david@kernel.org>
Date: 2026-09-09 13:35:08
Also in:
linux-cxl, linux-fsdevel, linux-mm, lkml
Subsystem:
memory management, memory management - core, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
Let's move it to sparse_init_one_section(). However, to keep early boot processing working, we also have to initialize it in sparse_sections_init(). Should we use READ_ONCE/WRITE_ONCE with __highest_used_section_nr? Probably, something for another day. Signed-off-by: David Hildenbrand (Arm) <david@kernel.org> --- mm/sparse.c | 5 +++-- mm/sparse.h | 6 +++--- 2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/mm/sparse.c b/mm/sparse.c
index 2b41ae36f20b8..2d0f2db34f4cf 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c@@ -177,7 +177,7 @@ static inline unsigned long first_present_section_nr(void) void __init sparse_sections_init(void) { - unsigned long pfn, start_pfn, end_pfn; + unsigned long pfn, start_pfn, end_pfn, section_nr; int i, nid; sparse_extreme_init();
@@ -187,9 +187,9 @@ void __init sparse_sections_init(void) mminit_validate_memmodel_limits(&start_pfn, &end_pfn); for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { - unsigned long section_nr = pfn_to_section_nr(pfn); struct mem_section *ms; + section_nr = pfn_to_section_nr(pfn); sparse_index_init(section_nr, nid); ms = __nr_to_section(section_nr); if (ms->section_mem_map)
@@ -201,6 +201,7 @@ void __init sparse_sections_init(void) __section_mark_present(ms, section_nr); } } + __highest_used_section_nr = section_nr; } #ifndef CONFIG_SPARSEMEM_VMEMMAP
diff --git a/mm/sparse.h b/mm/sparse.h
index 7c5d82ceb7142..a3af4967fd5c5 100644
--- a/mm/sparse.h
+++ b/mm/sparse.h@@ -97,6 +97,9 @@ static inline void sparse_init_one_section(struct mem_section *ms, BUILD_BUG_ON(SECTION_MAP_LAST_BIT > PFN_SECTION_SHIFT); + if (section_nr > __highest_used_section_nr) + __highest_used_section_nr = section_nr; + /* * We encode the start PFN of the section into the mem_map such that * page_to_pfn() on !CONFIG_SPARSEMEM_VMEMMAP can simply subtract it
@@ -114,9 +117,6 @@ static inline void sparse_init_one_section(struct mem_section *ms, static inline void __section_mark_present(struct mem_section *ms, unsigned long section_nr) { - if (section_nr > __highest_used_section_nr) - __highest_used_section_nr = section_nr; - ms->section_mem_map |= SECTION_MARKED_PRESENT; }
--
2.43.0