[PATCH v2 05/11] mm: track active portions of a section at boot

From: Dan Williams
Date: Thu Dec 08 2016 - 21:45:36 EST


Prepare for hot{plug,remove} of sub-ranges of a section by tracking a
section active bitmask, each bit representing 2MB (SECTION_SIZE (128M) /
map_active bitmask length (64)).

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Cc: Stephen Bates <stephen.bates@xxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
include/linux/mmzone.h | 3 +++
mm/page_alloc.c | 4 +++-
mm/sparse.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 5a0117a72ec4..e282dc328ada 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1083,6 +1083,8 @@ struct mem_section_usage {
unsigned long pageblock_flags[0];
};

+void section_active_init(unsigned long pfn, unsigned long nr_pages);
+
struct page;
struct page_ext;
struct mem_section {
@@ -1224,6 +1226,7 @@ void sparse_init(void);
#else
#define sparse_init() do {} while (0)
#define sparse_index_init(_sec, _nid) do {} while (0)
+#define section_active_init(_pfn, _nr_pages) do {} while (0)
#endif /* CONFIG_SPARSEMEM */

/*
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8a509e382f55..8dbfb131e358 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6308,10 +6308,12 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)

/* Print out the early node map */
pr_info("Early memory node ranges\n");
- for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
+ for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
pr_info(" node %3d: [mem %#018Lx-%#018Lx]\n", nid,
(u64)start_pfn << PAGE_SHIFT,
((u64)end_pfn << PAGE_SHIFT) - 1);
+ section_active_init(start_pfn, end_pfn - start_pfn);
+ }

/* Initialise every node */
mminit_verify_pageflags_layout();
diff --git a/mm/sparse.c b/mm/sparse.c
index 59966a3e8ff0..00fdb5d04680 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -168,6 +168,59 @@ void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn,
}
}

+static int section_active_index(phys_addr_t phys)
+{
+ return (phys & ~(PA_SECTION_MASK)) / SECTION_ACTIVE_SIZE;
+}
+
+static unsigned long section_active_mask(unsigned long pfn,
+ unsigned long nr_pages)
+{
+ int idx_start, idx_size;
+ phys_addr_t start, size;
+
+ if (!nr_pages)
+ return 0;
+
+ start = PFN_PHYS(pfn);
+ size = PFN_PHYS(min(nr_pages, PAGES_PER_SECTION
+ - (pfn & ~PAGE_SECTION_MASK)));
+ size = ALIGN(size, SECTION_ACTIVE_SIZE);
+
+ idx_start = section_active_index(start);
+ idx_size = section_active_index(size);
+
+ if (idx_size == 0)
+ return -1;
+ return ((1UL << idx_size) - 1) << idx_start;
+}
+
+void section_active_init(unsigned long pfn, unsigned long nr_pages)
+{
+ int end_sec = pfn_to_section_nr(pfn + nr_pages - 1);
+ int i, start_sec = pfn_to_section_nr(pfn);
+
+ if (!nr_pages)
+ return;
+
+ for (i = start_sec; i <= end_sec; i++) {
+ struct mem_section *ms;
+ unsigned long mask;
+ unsigned long pfns;
+
+ pfns = min(nr_pages, PAGES_PER_SECTION
+ - (pfn & ~PAGE_SECTION_MASK));
+ mask = section_active_mask(pfn, pfns);
+
+ ms = __nr_to_section(i);
+ pr_debug("%s: sec: %d mask: %#018lx\n", __func__, i, mask);
+ ms->usage->map_active = mask;
+
+ pfn += pfns;
+ nr_pages -= pfns;
+ }
+}
+
/* Record a memory area against a node. */
void __init memory_present(int nid, unsigned long start, unsigned long end)
{