Commit 37bc1502 authored by Baoquan He's avatar Baoquan He Committed by Linus Torvalds
Browse files

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.

Signed-off-by: default avatarBaoquan He <bhe@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Acked-by: default avatarPankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Link: http://lkml.kernel.org/r/20200312124414.439-3-bhe@redhat.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5d87255c

mm/sparse.c

+23 −8
Original line number Diff line number Diff line
@@ -705,15 +705,11 @@ static void free_map_bootmem(struct page *memmap) 
}

#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 long pfn, unsigned long nr_pages, 
	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 long pfn, unsigned long nr_pages, 
	 *

	 * 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);

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