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Commit fad7906d authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
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[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: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 5491d0f3

arch/x86_64/mm/srat.c

+11 −4
Original line number Diff line number Diff line
@@ -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);