mm, x86: remove MEMORY_HOTPLUG_RESERVE related code

after:

 | commit b263295dbffd33b0fbff670720fa178c30e3392a
 | Author: Christoph Lameter <clameter@sgi.com>
 | Date:   Wed Jan 30 13:30:47 2008 +0100
 |
 |    x86: 64-bit, make sparsemem vmemmap the only memory model

we don't have MEMORY_HOTPLUG_RESERVE anymore.

Historically, x86-64 had an architecture-specific method for memory hotplug
whereby it scanned the SRAT for physical memory ranges that could be
potentially used for memory hot-add later. By reserving those ranges
without physical memory, the memmap would be allocated and left dormant
until needed. This depended on the DISCONTIG memory model which has been
removed so the code implementing HOTPLUG_RESERVE is now dead.

This patch removes the dead code used by MEMORY_HOTPLUG_RESERVE.

(Changelog authored by Mel.)

v2: updated changelog, and remove hotadd= in doc

[ Impact: remove dead code ]

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: Mel Gorman <mel@csn.ul.ie>
Workflow-found-OK-by: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4A0C4910.7090508@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 12 insertions, 56 deletions

diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
index fb61d81a656f..a6a93c395231 100644
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -272,9 +272,6 @@ void __init setup_node_bootmem(int nodeid, unsigned long start,
                 reserve_bootmem_node(NODE_DATA(nodeid), bootmap_start,
                                  bootmap_pages<<PAGE_SHIFT, BOOTMEM_DEFAULT);
 
-#ifdef CONFIG_ACPI_NUMA
-        srat_reserve_add_area(nodeid);
-#endif
         node_set_online(nodeid);
 }
 
@@ -591,8 +588,6 @@ static __init int numa_setup(char *opt)
 #ifdef CONFIG_ACPI_NUMA
         if (!strncmp(opt, "noacpi", 6))
                 acpi_numa = -1;
-        if (!strncmp(opt, "hotadd=", 7))
-                hotadd_percent = simple_strtoul(opt+7, NULL, 10);
 #endif
         return 0;
 }
diff --git a/arch/x86/mm/srat_64.c b/arch/x86/mm/srat_64.c
index 87b45bff250d..b0dbbd48e58a 100644
--- a/arch/x86/mm/srat_64.c
+++ b/arch/x86/mm/srat_64.c
@@ -31,8 +31,6 @@ static nodemask_t nodes_parsed __initdata;
 static nodemask_t cpu_nodes_parsed __initdata;
 static struct bootnode nodes[MAX_NUMNODES] __initdata;
 static struct bootnode nodes_add[MAX_NUMNODES];
-static int found_add_area __initdata;
-int hotadd_percent __initdata = 0;
 
 static int num_node_memblks __initdata;
 static struct bootnode node_memblk_range[NR_NODE_MEMBLKS] __initdata;
@@ -66,9 +64,6 @@ static __init void cutoff_node(int i, unsigned long start, unsigned long end)
 {
         struct bootnode *nd = &nodes[i];
 
-        if (found_add_area)
-                return;
-
         if (nd->start < start) {
                 nd->start = start;
                 if (nd->end < nd->start)
@@ -86,7 +81,6 @@ static __init void bad_srat(void)
         int i;
         printk(KERN_ERR "SRAT: SRAT not used.\n");
         acpi_numa = -1;
-        found_add_area = 0;
         for (i = 0; i < MAX_LOCAL_APIC; i++)
                 apicid_to_node[i] = NUMA_NO_NODE;
         for (i = 0; i < MAX_NUMNODES; i++)
@@ -182,24 +176,21 @@ acpi_numa_processor_affinity_init(struct acpi_srat_cpu_affinity *pa)
                pxm, apic_id, node);
 }
 
-static int update_end_of_memory(unsigned long end) {return -1;}
-static int hotadd_enough_memory(struct bootnode *nd) {return 1;}
 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 static inline int save_add_info(void) {return 1;}
 #else
 static inline int save_add_info(void) {return 0;}
 #endif
 /*
- * Update nodes_add and decide if to include add are in the zone.
- * Both SPARSE and RESERVE need nodes_add information.
- * This code supports one contiguous hot add area per node.
+ * Update nodes_add[]
+ * This code supports one contiguous hot add area per node
  */
-static int __init
-reserve_hotadd(int node, unsigned long start, unsigned long end)
+static void __init
+update_nodes_add(int node, unsigned long start, unsigned long end)
 {
         unsigned long s_pfn = start >> PAGE_SHIFT;
         unsigned long e_pfn = end >> PAGE_SHIFT;
-        int ret = 0, changed = 0;
+        int changed = 0;
         struct bootnode *nd = &nodes_add[node];
 
         /* I had some trouble with strange memory hotadd regions breaking
@@ -210,7 +201,7 @@ reserve_hotadd(int node, unsigned long start, unsigned long end)
            mistakes */
         if ((signed long)(end - start) < NODE_MIN_SIZE) {
                 printk(KERN_ERR "SRAT: Hotplug area too small\n");
-                return -1;
+                return;
         }
 
         /* This check might be a bit too strict, but I'm keeping it for now. */
@@ -218,12 +209,7 @@ reserve_hotadd(int node, unsigned long start, unsigned long end)
                 printk(KERN_ERR
                         "SRAT: Hotplug area %lu -> %lu has existing memory\n",
                         s_pfn, e_pfn);
-                return -1;
-        }
-
-        if (!hotadd_enough_memory(&nodes_add[node]))  {
-                printk(KERN_ERR "SRAT: Hotplug area too large\n");
-                return -1;
+                return;
         }
 
         /* Looks good */
@@ -245,11 +231,9 @@ reserve_hotadd(int node, unsigned long start, unsigned long end)
                         printk(KERN_ERR "SRAT: Hotplug zone not continuous. Partly ignored\n");
         }
 
-        ret = update_end_of_memory(nd->end);
-
         if (changed)
-                printk(KERN_INFO "SRAT: hot plug zone found %Lx - %Lx\n", nd->start, nd->end);
-        return ret;
+                printk(KERN_INFO "SRAT: hot plug zone found %Lx - %Lx\n",
+                                 nd->start, nd->end);
 }
 
 /* Callback for parsing of the Proximity Domain <-> Memory Area mappings */
@@ -310,13 +294,10 @@ acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
                start, end);
         e820_register_active_regions(node, start >> PAGE_SHIFT,
                                      end >> PAGE_SHIFT);
-        push_node_boundaries(node, nd->start >> PAGE_SHIFT,
-                                                nd->end >> PAGE_SHIFT);
 
-        if ((ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE) &&
-            (reserve_hotadd(node, start, end) < 0)) {
-                /* Ignore hotadd region. Undo damage */
-                printk(KERN_NOTICE "SRAT: Hotplug region ignored\n");
+        if (ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE) {
+                update_nodes_add(node, start, end);
+                /* restore nodes[node] */
                 *nd = oldnode;
                 if ((nd->start | nd->end) == 0)
                         node_clear(node, nodes_parsed);
@@ -510,26 +491,6 @@ static int null_slit_node_compare(int a, int b)
 }
 #endif /* CONFIG_NUMA_EMU */
 
-void __init srat_reserve_add_area(int nodeid)
-{
-        if (found_add_area && nodes_add[nodeid].end) {
-                u64 total_mb;
-
-                printk(KERN_INFO "SRAT: Reserving hot-add memory space "
-                                "for node %d at %Lx-%Lx\n",
-                        nodeid, nodes_add[nodeid].start, nodes_add[nodeid].end);
-                total_mb = (nodes_add[nodeid].end - nodes_add[nodeid].start)
-                                        >> PAGE_SHIFT;
-                total_mb *= sizeof(struct page);
-                total_mb >>= 20;
-                printk(KERN_INFO "SRAT: This will cost you %Lu MB of "
-                                "pre-allocated memory.\n", (unsigned long long)total_mb);
-                reserve_bootmem_node(NODE_DATA(nodeid), nodes_add[nodeid].start,
-                               nodes_add[nodeid].end - nodes_add[nodeid].start,
-                               BOOTMEM_DEFAULT);
-        }
-}
-
 int __node_distance(int a, int b)
 {
         int index;