linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH] mm/sparse: only sub-section aligned range would be populated
@ 2020-06-30  2:14 Wei Yang
  2020-06-30 12:52 ` David Hildenbrand
  2020-06-30 18:11 ` kernel test robot
  0 siblings, 2 replies; 8+ messages in thread
From: Wei Yang @ 2020-06-30  2:14 UTC (permalink / raw)
  To: dan.j.williams, akpm; +Cc: linux-mm, linux-kernel, Wei Yang

There are two code path which invoke __populate_section_memmap()

  * sparse_init_nid()
  * sparse_add_section()

For both case, we are sure the memory range is sub-section aligned.

  * we pass PAGES_PER_SECTION to sparse_init_nid()
  * we check range by check_pfn_span() before calling
    sparse_add_section()

Also, the counterpart of __populate_section_memmap(), we don't do such
calculation and check since the range is checked by check_pfn_span() in
__remove_pages().

Clear the calculation and check to keep it simple and comply with its
counterpart.

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
---
 mm/sparse-vmemmap.c | 16 ++--------------
 1 file changed, 2 insertions(+), 14 deletions(-)

diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index 0db7738d76e9..24b01ebae111 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -247,20 +247,8 @@ int __meminit vmemmap_populate_basepages(unsigned long start,
 struct page * __meminit __populate_section_memmap(unsigned long pfn,
 		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
 {
-	unsigned long start;
-	unsigned long end;
-
-	/*
-	 * The minimum granularity of memmap extensions is
-	 * PAGES_PER_SUBSECTION as allocations are tracked in the
-	 * 'subsection_map' bitmap of the section.
-	 */
-	end = ALIGN(pfn + nr_pages, PAGES_PER_SUBSECTION);
-	pfn &= PAGE_SUBSECTION_MASK;
-	nr_pages = end - pfn;
-
-	start = (unsigned long) pfn_to_page(pfn);
-	end = start + nr_pages * sizeof(struct page);
+	unsigned long start = (unsigned long) pfn_to_page(pfn);
+	unsigned long end = start + nr_pages * sizeof(struct page);
 
 	if (vmemmap_populate(start, end, nid, altmap))
 		return NULL;
-- 
2.20.1 (Apple Git-117)


^ permalink raw reply related	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2020-07-09  0:20 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-30  2:14 [PATCH] mm/sparse: only sub-section aligned range would be populated Wei Yang
2020-06-30 12:52 ` David Hildenbrand
2020-07-01  2:32   ` Wei Yang
2020-07-01  9:27     ` David Hildenbrand
2020-06-30 18:11 ` kernel test robot
2020-07-01 11:58   ` Wei Yang
     [not found]     ` <MN2PR11MB4064B0104312A3D22F1698F3E5670@MN2PR11MB4064.namprd11.prod.outlook.com>
2020-07-08 18:20       ` Nick Desaulniers
2020-07-09  0:20         ` Philip Li

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).