[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>

diff --git a/arch/x86_64/mm/srat.c b/arch/x86_64/mm/srat.c
index 15ae9fcd65a700c9f9060860f0fce56f7f6f3fcf..e1513532df293447a529cd7477b6bbca67363e18 100644 (file)
--- 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);