The patch titled
Subject: mm/sparse.c: introduce a new function clear_subsection_map()
has been added to the -mm tree. Its filename is
mm-sparsec-introduce-a-new-function-clear_subsection_map.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-sparsec-introduce-a-new-function-clear_subsection_map.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-sparsec-introduce-a-new-function-clear_subsection_map.patch
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------------------------------------------------------
From: Baoquan He <bhe@xxxxxxxxxx>
Subject: mm/sparse.c: introduce a new function clear_subsection_map()
Factor out the code which clear subsection map of one memory region from
section_deactivate() into clear_subsection_map().
And also add helper function is_subsection_map_empty() to check if the
current subsection map is empty or not.
Link: http://lkml.kernel.org/r/20200312124414.439-3-bhe@xxxxxxxxxx
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/sparse.c | 31 +++++++++++++++++++++++--------
1 file changed, 23 insertions(+), 8 deletions(-)
--- a/mm/sparse.c~mm-sparsec-introduce-a-new-function-clear_subsection_map
+++ a/mm/sparse.c
@@ -705,15 +705,11 @@ static void free_map_bootmem(struct page
}
#endif /* CONFIG_SPARSEMEM_VMEMMAP */
-static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
- struct vmem_altmap *altmap)
+static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages)
{
DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 };
struct mem_section *ms = __pfn_to_section(pfn);
- bool section_is_early = early_section(ms);
- struct page *memmap = NULL;
- bool empty;
unsigned long *subsection_map = ms->usage
? &ms->usage->subsection_map[0] : NULL;
@@ -724,8 +720,28 @@ static void section_deactivate(unsigned
if (WARN(!subsection_map || !bitmap_equal(tmp, map, SUBSECTIONS_PER_SECTION),
"section already deactivated (%#lx + %ld)\n",
pfn, nr_pages))
- return;
+ return -EINVAL;
+
+ bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION);
+ return 0;
+}
+
+static bool is_subsection_map_empty(struct mem_section *ms)
+{
+ return bitmap_empty(&ms->usage->subsection_map[0],
+ SUBSECTIONS_PER_SECTION);
+}
+static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
+ struct vmem_altmap *altmap)
+{
+ struct mem_section *ms = __pfn_to_section(pfn);
+ bool section_is_early = early_section(ms);
+ struct page *memmap = NULL;
+ bool empty;
+
+ if (clear_subsection_map(pfn, nr_pages))
+ return;
/*
* There are 3 cases to handle across two configurations
* (SPARSEMEM_VMEMMAP={y,n}):
@@ -743,8 +759,7 @@ static void section_deactivate(unsigned
*
* For 2/ and 3/ the SPARSEMEM_VMEMMAP={y,n} cases are unified
*/
- bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION);
- empty = bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION);
+ empty = is_subsection_map_empty(ms);
if (empty) {
unsigned long section_nr = pfn_to_section_nr(pfn);
_
Patches currently in -mm which might be from bhe@xxxxxxxxxx are
mm-hotplug-fix-hot-remove-failure-in-sparsememvmemmap-case.patch
mm-sparsec-use-kvmalloc_node-kvfree-to-alloc-free-memmap-for-the-classic-sparse.patch
mm-hotplug-only-respect-mem=-parameter-during-boot-stage.patch
mm-sparsec-introduce-new-function-fill_subsection_map.patch
mm-sparsec-introduce-a-new-function-clear_subsection_map.patch
mm-sparsec-only-use-subsection-map-in-vmemmap-case.patch
mm-sparsec-add-note-about-only-vmemmap-supporting-sub-section-hotplug.patch
mm-sparsec-move-subsection_map-related-functions-together.patch
