mm/page_alloc.c: introduce kernelcore=mirror option

This patch extends existing "kernelcore" option and introduces
kernelcore=mirror option.  By specifying "mirror" instead of specifying
the amount of memory, non-mirrored (non-reliable) region will be
arranged into ZONE_MOVABLE.

[akpm@linux-foundation.org: fix build with CONFIG_HAVE_MEMBLOCK_NODE_MAP=n]
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Steve Capper <steve.capper@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 108 insertions, 6 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0d20a19151a4..b8160b9d5e72 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -247,6 +247,7 @@ static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
 static unsigned long __initdata required_kernelcore;
 static unsigned long __initdata required_movablecore;
 static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
+static bool mirrored_kernelcore;
 
 /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
 int movable_zone;
@@ -4491,6 +4492,9 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
         pg_data_t *pgdat = NODE_DATA(nid);
         unsigned long pfn;
         unsigned long nr_initialised = 0;
+#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
+        struct memblock_region *r = NULL, *tmp;
+#endif
 
         if (highest_memmap_pfn < end_pfn - 1)
                 highest_memmap_pfn = end_pfn - 1;
@@ -4516,6 +4520,40 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
                         if (!update_defer_init(pgdat, pfn, end_pfn,
                                                 &nr_initialised))
                                 break;
+
+#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
+                        /*
+                         * if not mirrored_kernelcore and ZONE_MOVABLE exists,
+                         * range from zone_movable_pfn[nid] to end of each node
+                         * should be ZONE_MOVABLE not ZONE_NORMAL. skip it.
+                         */
+                        if (!mirrored_kernelcore && zone_movable_pfn[nid])
+                                if (zone == ZONE_NORMAL &&
+                                    pfn >= zone_movable_pfn[nid])
+                                        continue;
+
+                        /*
+                         * check given memblock attribute by firmware which
+                         * can affect kernel memory layout.
+                         * if zone==ZONE_MOVABLE but memory is mirrored,
+                         * it's an overlapped memmap init. skip it.
+                         */
+                        if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
+                                if (!r ||
+                                    pfn >= memblock_region_memory_end_pfn(r)) {
+                                        for_each_memblock(memory, tmp)
+                                                if (pfn < memblock_region_memory_end_pfn(tmp))
+                                                        break;
+                                        r = tmp;
+                                }
+                                if (pfn >= memblock_region_memory_base_pfn(r) &&
+                                    memblock_is_mirror(r)) {
+                                        /* already initialized as NORMAL */
+                                        pfn = memblock_region_memory_end_pfn(r);
+                                        continue;
+                                }
+                        }
+#endif
                 }
 
                 /*
@@ -4934,11 +4972,6 @@ static void __meminit adjust_zone_range_for_zone_movable(int nid,
                         *zone_end_pfn = min(node_end_pfn,
                                 arch_zone_highest_possible_pfn[movable_zone]);
 
-                /* Adjust for ZONE_MOVABLE starting within this range */
-                } else if (*zone_start_pfn < zone_movable_pfn[nid] &&
-                                *zone_end_pfn > zone_movable_pfn[nid]) {
-                        *zone_end_pfn = zone_movable_pfn[nid];
-
                 /* Check if this whole range is within ZONE_MOVABLE */
                 } else if (*zone_start_pfn >= zone_movable_pfn[nid])
                         *zone_start_pfn = *zone_end_pfn;
@@ -5023,6 +5056,7 @@ static unsigned long __meminit zone_absent_pages_in_node(int nid,
         unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
         unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
         unsigned long zone_start_pfn, zone_end_pfn;
+        unsigned long nr_absent;
 
         /* When hotadd a new node from cpu_up(), the node should be empty */
         if (!node_start_pfn && !node_end_pfn)
@@ -5034,7 +5068,39 @@ static unsigned long __meminit zone_absent_pages_in_node(int nid,
         adjust_zone_range_for_zone_movable(nid, zone_type,
                         node_start_pfn, node_end_pfn,
                         &zone_start_pfn, &zone_end_pfn);
-        return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
+        nr_absent = __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
+
+        /*
+         * ZONE_MOVABLE handling.
+         * Treat pages to be ZONE_MOVABLE in ZONE_NORMAL as absent pages
+         * and vice versa.
+         */
+        if (zone_movable_pfn[nid]) {
+                if (mirrored_kernelcore) {
+                        unsigned long start_pfn, end_pfn;
+                        struct memblock_region *r;
+
+                        for_each_memblock(memory, r) {
+                                start_pfn = clamp(memblock_region_memory_base_pfn(r),
+                                                  zone_start_pfn, zone_end_pfn);
+                                end_pfn = clamp(memblock_region_memory_end_pfn(r),
+                                                zone_start_pfn, zone_end_pfn);
+
+                                if (zone_type == ZONE_MOVABLE &&
+                                    memblock_is_mirror(r))
+                                        nr_absent += end_pfn - start_pfn;
+
+                                if (zone_type == ZONE_NORMAL &&
+                                    !memblock_is_mirror(r))
+                                        nr_absent += end_pfn - start_pfn;
+                        }
+                } else {
+                        if (zone_type == ZONE_NORMAL)
+                                nr_absent += node_end_pfn - zone_movable_pfn[nid];
+                }
+        }
+
+        return nr_absent;
 }
 
 #else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
@@ -5547,6 +5613,36 @@ static void __init find_zone_movable_pfns_for_nodes(void)
         }
 
         /*
+         * If kernelcore=mirror is specified, ignore movablecore option
+         */
+        if (mirrored_kernelcore) {
+                bool mem_below_4gb_not_mirrored = false;
+
+                for_each_memblock(memory, r) {
+                        if (memblock_is_mirror(r))
+                                continue;
+
+                        nid = r->nid;
+
+                        usable_startpfn = memblock_region_memory_base_pfn(r);
+
+                        if (usable_startpfn < 0x100000) {
+                                mem_below_4gb_not_mirrored = true;
+                                continue;
+                        }
+
+                        zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
+                                min(usable_startpfn, zone_movable_pfn[nid]) :
+                                usable_startpfn;
+                }
+
+                if (mem_below_4gb_not_mirrored)
+                        pr_warn("This configuration results in unmirrored kernel memory.");
+
+                goto out2;
+        }
+
+        /*
          * If movablecore=nn[KMG] was specified, calculate what size of
          * kernelcore that corresponds so that memory usable for
          * any allocation type is evenly spread. If both kernelcore
@@ -5806,6 +5902,12 @@ static int __init cmdline_parse_core(char *p, unsigned long *core)
  */
 static int __init cmdline_parse_kernelcore(char *p)
 {
+        /* parse kernelcore=mirror */
+        if (parse_option_str(p, "mirror")) {
+                mirrored_kernelcore = true;
+                return 0;
+        }
+
         return cmdline_parse_core(p, &required_kernelcore);
 }