[PATCH] x86_64: Reserve SRAT hotadd memory on x86-64
From: Keith Mannthey, Andi Kleen
Implement memory hotadd without sparsemem. The memory in the SRAT
hotadd area is just preserved instead and can be activated later.
There are a few restrictions:
- Only one continuous hotadd area allowed per node
The main problem is dealing with the many buggy SRAT tables
that are out there. The strategy here is to reject anything
suspicious.
Originally from Keith Mannthey, with several hacks and changes by AK
and also contributions from Andrew Morton
[ TBD: Problems pointed out by KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>:
1) Goto's rebuild_zonelist patch will not work if CONFIG_MEMORY_HOTPLUG=n.
Rebuilding zonelist is necessary when the system has just memory <
4G at boot, and hot add memory > 4G. because x86_64 has DMA32,
ZONE_NORAML is not included into zonelist at boot time if system
doesn't have memory >4G at boot.
[AK: should just force the higher zones at boot time when SRAT tells us]
2) zone and node's spanned_pages and present_pages are not incremented.
They should be.
For example, our server (ia64/Fujitsu PrimeQuest) can equip memory
from 4G to 1T(maybe 2T in future), and SRAT will *always* say we have
possible 1T +memory. (Microsoft requires "write all possible memory
in SRAT") When we reserve memmap for possible 1T memory, Linux will
not work well in +minimum 4G configuraion ;)
[AK: needs limiting to 5-10% of max memory]
]
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index 4921611..dff8705 100644
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -530,8 +530,7 @@
unsigned long pfn;
unsigned long total = 0, mem = 0;
for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++) {
- unsigned long addr = pfn << PAGE_SHIFT;
- if (pfn_valid(pfn) && e820_mapped(addr, addr+1, E820_RAM)) {
+ if (pfn_valid(pfn)) {
online_page(pfn_to_page(pfn));
err = 0;
mem++;
diff --git a/arch/x86_64/mm/numa.c b/arch/x86_64/mm/numa.c
index 4be82d6..779132a 100644
--- a/arch/x86_64/mm/numa.c
+++ b/arch/x86_64/mm/numa.c
@@ -142,6 +142,9 @@
reserve_bootmem_node(NODE_DATA(nodeid), nodedata_phys, pgdat_size);
reserve_bootmem_node(NODE_DATA(nodeid), bootmap_start, bootmap_pages<<PAGE_SHIFT);
+#ifdef CONFIG_ACPI_NUMA
+ srat_reserve_add_area(nodeid);
+#endif
node_set_online(nodeid);
}
@@ -335,6 +338,8 @@
#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 1;
}
diff --git a/arch/x86_64/mm/srat.c b/arch/x86_64/mm/srat.c
index 2eb8795..443875e 100644
--- a/arch/x86_64/mm/srat.c
+++ b/arch/x86_64/mm/srat.c
@@ -15,15 +15,26 @@
#include <linux/bitmap.h>
#include <linux/module.h>
#include <linux/topology.h>
+#include <linux/bootmem.h>
+#include <linux/mm.h>
#include <asm/proto.h>
#include <asm/numa.h>
#include <asm/e820.h>
+#if (defined(CONFIG_ACPI_HOTPLUG_MEMORY) || \
+ defined(CONFIG_ACPI_HOTPLUG_MEMORY_MODULE)) \
+ && !defined(CONFIG_MEMORY_HOTPLUG)
+#define RESERVE_HOTADD 1
+#endif
+
static struct acpi_table_slit *acpi_slit;
static nodemask_t nodes_parsed __initdata;
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;
static u8 pxm2node[256] = { [0 ... 255] = 0xff };
/* Too small nodes confuse the VM badly. Usually they result
@@ -71,6 +82,10 @@
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)
@@ -90,6 +105,8 @@
acpi_numa = -1;
for (i = 0; i < MAX_LOCAL_APIC; i++)
apicid_to_node[i] = NUMA_NO_NODE;
+ for (i = 0; i < MAX_NUMNODES; i++)
+ nodes_add[i].start = nodes[i].end = 0;
}
static __init inline int srat_disabled(void)
@@ -155,11 +172,114 @@
pxm, pa->apic_id, node);
}
+#ifdef RESERVE_HOTADD
+/*
+ * Protect against too large hotadd areas that would fill up memory.
+ */
+static int hotadd_enough_memory(struct bootnode *nd)
+{
+ static unsigned long allocated;
+ static unsigned long last_area_end;
+ unsigned long pages = (nd->end - nd->start) >> PAGE_SHIFT;
+ long mem = pages * sizeof(struct page);
+ unsigned long addr;
+ unsigned long allowed;
+ unsigned long oldpages = pages;
+
+ if (mem < 0)
+ return 0;
+ allowed = (end_pfn - e820_hole_size(0, end_pfn)) * PAGE_SIZE;
+ allowed = (allowed / 100) * hotadd_percent;
+ if (allocated + mem > allowed) {
+ /* 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);
+ mem = pages * sizeof(struct page);
+ nd->end = nd->start + pages*PAGE_SIZE;
+ }
+ /* Not completely fool proof, but a good sanity check */
+ addr = find_e820_area(last_area_end, end_pfn<<PAGE_SHIFT, mem);
+ if (addr == -1UL)
+ return 0;
+ if (pages != oldpages)
+ printk(KERN_NOTICE "SRAT: Hotadd area limited to %lu bytes\n",
+ pages << PAGE_SHIFT);
+ last_area_end = addr + mem;
+ allocated += mem;
+ return 1;
+}
+
+/*
+ * It is fine to add this area to the nodes data it will be used later
+ * This code supports one contigious hot add area per node.
+ */
+static int reserve_hotadd(int node, unsigned long start, unsigned long end)
+{
+ unsigned long s_pfn = start >> PAGE_SHIFT;
+ unsigned long e_pfn = end >> PAGE_SHIFT;
+ int changed = 0;
+ struct bootnode *nd = &nodes_add[node];
+
+ /* I had some trouble with strange memory hotadd regions breaking
+ the boot. Be very strict here and reject anything unexpected.
+ If you want working memory hotadd write correct SRATs.
+
+ The node size check is a basic sanity check to guard against
+ mistakes */
+ if ((signed long)(end - start) < NODE_MIN_SIZE) {
+ printk(KERN_ERR "SRAT: Hotplug area too small\n");
+ return -1;
+ }
+
+ /* This check might be a bit too strict, but I'm keeping it for now. */
+ if (e820_hole_size(s_pfn, e_pfn) != e_pfn - s_pfn) {
+ printk(KERN_ERR "SRAT: Hotplug area has existing memory\n");
+ return -1;
+ }
+
+ if (!hotadd_enough_memory(&nodes_add[node])) {
+ printk(KERN_ERR "SRAT: Hotplug area too large\n");
+ return -1;
+ }
+
+ /* Looks good */
+
+ found_add_area = 1;
+ if (nd->start == nd->end) {
+ nd->start = start;
+ nd->end = end;
+ changed = 1;
+ } else {
+ if (nd->start == end) {
+ nd->start = start;
+ changed = 1;
+ }
+ if (nd->end == start) {
+ nd->end = end;
+ changed = 1;
+ }
+ if (!changed)
+ printk(KERN_ERR "SRAT: Hotplug zone not continuous. Partly ignored\n");
+ }
+
+ if ((nd->end >> PAGE_SHIFT) > end_pfn)
+ end_pfn = nd->end >> PAGE_SHIFT;
+
+ if (changed)
+ printk(KERN_INFO "SRAT: hot plug zone found %Lx - %Lx\n", nd->start, nd->end);
+ return 0;
+}
+#endif
+
/* Callback for parsing of the Proximity Domain <-> Memory Area mappings */
void __init
acpi_numa_memory_affinity_init(struct acpi_table_memory_affinity *ma)
{
- struct bootnode *nd;
+ struct bootnode *nd, oldnode;
unsigned long start, end;
int node, pxm;
int i;
@@ -172,6 +292,8 @@
}
if (ma->flags.enabled == 0)
return;
+ if (ma->flags.hot_pluggable && hotadd_percent == 0)
+ return;
start = ma->base_addr_lo | ((u64)ma->base_addr_hi << 32);
end = start + (ma->length_lo | ((u64)ma->length_hi << 32));
pxm = ma->proximity_domain;
@@ -181,10 +303,6 @@
bad_srat();
return;
}
- /* It is fine to add this area to the nodes data it will be used later*/
- if (ma->flags.hot_pluggable == 1)
- printk(KERN_INFO "SRAT: hot plug zone found %lx - %lx \n",
- start, end);
i = conflicting_nodes(start, end);
if (i == node) {
printk(KERN_WARNING
@@ -199,6 +317,7 @@
return;
}
nd = &nodes[node];
+ oldnode = *nd;
if (!node_test_and_set(node, nodes_parsed)) {
nd->start = start;
nd->end = end;
@@ -208,8 +327,19 @@
if (nd->end < end)
nd->end = end;
}
+
printk(KERN_INFO "SRAT: Node %u PXM %u %Lx-%Lx\n", node, pxm,
nd->start, nd->end);
+
+#ifdef RESERVE_HOTADD
+ if (ma->flags.hot_pluggable && reserve_hotadd(node, start, end) < 0) {
+ /* Ignore hotadd region. Undo damage */
+ printk(KERN_NOTICE "SRAT: Hotplug region ignored\n");
+ *nd = oldnode;
+ if ((nd->start | nd->end) == 0)
+ node_clear(node, nodes_parsed);
+ }
+#endif
}
/* Sanity check to catch more bad SRATs (they are amazingly common).
@@ -225,6 +355,9 @@
unsigned long e = nodes[i].end >> PAGE_SHIFT;
pxmram += e - s;
pxmram -= e820_hole_size(s, e);
+ pxmram -= nodes_add[i].end - nodes_add[i].start;
+ if ((long)pxmram < 0)
+ pxmram = 0;
}
e820ram = end_pfn - e820_hole_size(0, end_pfn);
@@ -258,7 +391,7 @@
/* First clean up the node list */
for (i = 0; i < MAX_NUMNODES; i++) {
- cutoff_node(i, start, end);
+ cutoff_node(i, start, end);
if ((nodes[i].end - nodes[i].start) < NODE_MIN_SIZE)
unparse_node(i);
}
@@ -303,6 +436,25 @@
return 0;
}
+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);
+ }
+}
+
int __node_distance(int a, int b)
{
int index;