[PATCH] x86_64: Fix memory hotadd heuristics

This fixes some boot failures on Dell and Unisys systems with memory
hotadd added.

 - Set hotadd_percent to 0 by default.  This means anybody using hotadd
   memory needs to specify the value on the command line.  That's
   because there are lots of Intel boxes which have a bogus hotplug area
   in their SRAT and they would waste a lot of memory before.
 - Fix calculation of how much memory to use when the hotplug area
   exceeds hotadd_percent
 - Fix fallback when the
 - Fix fallback if memory hotadd is not compiled in.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 11 insertions, 4 deletions

diff --git a/arch/x86_64/mm/srat.c b/arch/x86_64/mm/srat.c
index 15ae9fcd65a7..e1513532df29 100644
--- a/arch/x86_64/mm/srat.c
+++ b/arch/x86_64/mm/srat.c
@@ -34,7 +34,10 @@ static nodemask_t nodes_found __initdata;
 static struct bootnode nodes[MAX_NUMNODES] __initdata;
 static struct bootnode nodes_add[MAX_NUMNODES] __initdata;
 static int found_add_area __initdata;
-int hotadd_percent __initdata = 10;
+int hotadd_percent __initdata = 0;
+#ifndef RESERVE_HOTADD
+#define hotadd_percent 0        /* Ignore all settings */
+#endif
 static u8 pxm2node[256] = { [0 ... 255] = 0xff };
 
 /* Too small nodes confuse the VM badly. Usually they result
@@ -103,6 +106,7 @@ 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++)
@@ -154,7 +158,8 @@ acpi_numa_processor_affinity_init(struct acpi_table_processor_affinity *pa)
         int pxm, node;
         if (srat_disabled())
                 return;
-        if (pa->header.length != sizeof(struct acpi_table_processor_affinity)) {                bad_srat();
+        if (pa->header.length != sizeof(struct acpi_table_processor_affinity)) {
+                bad_srat();
                 return;
         }
         if (pa->flags.enabled == 0)
@@ -191,15 +196,17 @@ static int hotadd_enough_memory(struct bootnode *nd)
         allowed = (end_pfn - e820_hole_size(0, end_pfn)) * PAGE_SIZE;
         allowed = (allowed / 100) * hotadd_percent;
         if (allocated + mem > allowed) {
+                unsigned long range;
                 /* Give them at least part of their hotadd memory upto hotadd_percent
                    It would be better to spread the limit out
                    over multiple hotplug areas, but that is too complicated
                    right now */
                 if (allocated >= allowed)
                         return 0;
-                pages = (allowed - allocated + mem) / sizeof(struct page);
+                range = allowed - allocated;
+                pages = (range / PAGE_SIZE);
                 mem = pages * sizeof(struct page);
-                nd->end = nd->start + pages*PAGE_SIZE;
+                nd->end = nd->start + range;
         }
         /* Not completely fool proof, but a good sanity check */
         addr = find_e820_area(last_area_end, end_pfn<<PAGE_SHIFT, mem);