Hi,
Currently there is fully working version.
It has been tested on Xen Ver. 4.0.0 in PV
guest i386/x86_64 with Linux kernel Ver. 2.6.32.16
and Ver. 2.6.34.1. This patch cleanly applys
to Ver. 2.6.34.1 (also as attachment because
I received some reports that my patches are
mangled). All found bugs have been removed
(Sorry however I am sure that some hidden
still exists :-((().
This patch enables two modes of operation:
- enabled by CONFIG_XEN_MEMORY_HOTPLUG config option:
- set memory limit for chosen domU from dom0:
xm mem-max <domU> <new_memory_size_limit>
- add memory in chosen domU: echo <unused_address> > \
/sys/devices/system/memory/probe; memory is added
in sections which sizes differ from arch to arch
(i386: 512 MiB, x86_64: 128 MiB; it could by checked
by cat /sys/devices/system/memory/block_size_bytes;
this value is in HEX); it is preffered to choose
address at section boundary,
- online memory in chosen domU: echo online > \
/sys/devices/system/memory/memory<section_number>/state;
<section_number> could be established in following manner:
(int)(<unused_address> / <section_size>)
- enabled by CONFIG_XEN_BALLOON_MEMORY_HOTPLUG config option:
- set memory limit for chosen domU from dom0:
xm mem-max <domU> <new_memory_size_limit>
- add memory for chosen domU from dom0:
xm mem-set <domU> <new_memory_size>
If you have a questions please drop me a line.
Daniel
Signed-off-by: Daniel Kiper <dkiper@xxxxxxxxxxxx>
---
arch/x86/Kconfig | 2 +-
drivers/base/memory.c | 23 +++++
drivers/xen/Kconfig | 10 ++
drivers/xen/balloon.c | 196 +++++++++++++++++++++++++++++++++++++++-
include/linux/memory_hotplug.h | 8 ++
include/xen/balloon.h | 6 ++
mm/Kconfig | 9 ++
mm/memory_hotplug.c | 140 ++++++++++++++++++++++++++++
8 files changed, 390 insertions(+), 4 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 9458685..38434da 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1273,7 +1273,7 @@ config ARCH_SELECT_MEMORY_MODEL
depends on ARCH_SPARSEMEM_ENABLE
config ARCH_MEMORY_PROBE
- def_bool X86_64
+ def_bool y
depends on MEMORY_HOTPLUG
config ILLEGAL_POINTER_VALUE
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 933442f..709457b 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -27,6 +27,14 @@
#include <asm/atomic.h>
#include <asm/uaccess.h>
+#ifdef CONFIG_XEN_MEMORY_HOTPLUG
+#include <xen/xen.h>
+#endif
+
+#if defined(CONFIG_XEN_MEMORY_HOTPLUG) && defined(CONFIG_XEN_BALLOON)
+#include <xen/balloon.h>
+#endif
+
#define MEMORY_CLASS_NAME "memory"
static struct sysdev_class memory_sysdev_class = {
@@ -215,6 +223,10 @@ memory_block_action(struct memory_block *mem, unsigned long action)
case MEM_ONLINE:
start_pfn = page_to_pfn(first_page);
ret = online_pages(start_pfn, PAGES_PER_SECTION);
+#if defined(CONFIG_XEN_MEMORY_HOTPLUG) && defined(CONFIG_XEN_BALLOON)
+ if (xen_domain() && !ret)
+ balloon_update_stats(PAGES_PER_SECTION);
+#endif
break;
case MEM_OFFLINE:
mem->state = MEM_GOING_OFFLINE;
@@ -225,6 +237,10 @@ memory_block_action(struct memory_block *mem, unsigned long action)
mem->state = old_state;
break;
}
+#if defined(CONFIG_XEN_MEMORY_HOTPLUG) && defined(CONFIG_XEN_BALLOON)
+ if (xen_domain())
+ balloon_update_stats(-PAGES_PER_SECTION);
+#endif
break;
default:
WARN(1, KERN_WARNING "%s(%p, %ld) unknown action: %ld\n",
@@ -341,6 +357,13 @@ memory_probe_store(struct class *class, struct class_attribute *attr,
phys_addr = simple_strtoull(buf, NULL, 0);
+#ifdef CONFIG_XEN_MEMORY_HOTPLUG
+ if (xen_domain()) {
+ ret = xen_memory_probe(phys_addr);
+ return ret ? ret : count;
+ }
+#endif
+
nid = memory_add_physaddr_to_nid(phys_addr);
ret = add_memory(nid, phys_addr, PAGES_PER_SECTION << PAGE_SHIFT);
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index fad3df2..9713048 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -9,6 +9,16 @@ config XEN_BALLOON
the system to expand the domain's memory allocation, or alternatively
return unneeded memory to the system.
+config XEN_BALLOON_MEMORY_HOTPLUG
+ bool "Xen memory balloon driver with memory hotplug support"
+ depends on EXPERIMENTAL && XEN_BALLOON && MEMORY_HOTPLUG
+ default n
+ help
+ Xen memory balloon driver with memory hotplug support allows expanding
+ memory available for the system above limit declared at system startup.
+ It is very useful on critical systems which require long run without
+ rebooting.
+
config XEN_SCRUB_PAGES
bool "Scrub pages before returning them to system"
depends on XEN_BALLOON
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 1a0d8c2..f80bba0 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -6,6 +6,7 @@
* Copyright (c) 2003, B Dragovic
* Copyright (c) 2003-2004, M Williamson, K Fraser
* Copyright (c) 2005 Dan M. Smith, IBM Corporation
+ * Copyright (c) 2010 Daniel Kiper
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
@@ -61,6 +62,10 @@
#include <xen/features.h>
#include <xen/page.h>
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+#include <linux/memory.h>
+#endif
+
#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
#define BALLOON_CLASS_NAME "xen_memory"
@@ -77,6 +82,11 @@ struct balloon_stats {
/* Number of pages in high- and low-memory balloons. */
unsigned long balloon_low;
unsigned long balloon_high;
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ unsigned long boot_max_pfn;
+ u64 hotplug_start_paddr;
+ u64 hotplug_size;
+#endif
};
static DEFINE_MUTEX(balloon_mutex);
@@ -184,6 +194,12 @@ static void balloon_alarm(unsigned long unused)
schedule_work(&balloon_worker);
}
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+static inline unsigned long current_target(void)
+{
+ return balloon_stats.target_pages;
+}
+#else
static unsigned long current_target(void)
{
unsigned long target = balloon_stats.target_pages;
@@ -195,11 +211,12 @@ static unsigned long current_target(void)
return target;
}
+#endif
static int increase_reservation(unsigned long nr_pages)
{
- unsigned long pfn, i, flags;
- struct page *page;
+ unsigned long uninitialized_var(pfn), i, flags;
+ struct page *uninitialized_var(page);
long rc;
struct xen_memory_reservation reservation = {
.address_bits = 0,
@@ -207,11 +224,63 @@ static int increase_reservation(unsigned long nr_pages)
.domid = DOMID_SELF
};
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ resource_size_t r_min, r_size;
+ struct resource *r;
+#endif
+
if (nr_pages > ARRAY_SIZE(frame_list))
nr_pages = ARRAY_SIZE(frame_list);
spin_lock_irqsave(&balloon_lock, flags);
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ if (!balloon_stats.balloon_low && !balloon_stats.balloon_high) {
+ if (!balloon_stats.hotplug_start_paddr) {
+
+ /*
+ * Look for first unused memory region starting
+ * at page boundary. Skip last memory section created
+ * at boot time becuase it may contains unused memory
+ * pages with PG_reserved bit not set (online_pages
+ * require PG_reserved bit set).
+ */
+
+ r = kzalloc(sizeof(struct resource), GFP_KERNEL);
+
+ if (!r) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ r->name = "System RAM";
+ r->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+ r_min = PFN_PHYS(section_nr_to_pfn(pfn_to_section_nr(balloon_stats.boot_max_pfn) + 1));
+ r_size = (balloon_stats.target_pages - balloon_stats.current_pages) << PAGE_SHIFT;
+
+ rc = allocate_resource(&iomem_resource, r,
+ r_size, r_min, ULONG_MAX,
+ PAGE_SIZE, NULL, NULL);
+
+ if (rc < 0) {
+ kfree(r);
+ goto out;
+ }
+
+ balloon_stats.hotplug_start_paddr = r->start;
+ }
+
+ pfn = PFN_DOWN(balloon_stats.hotplug_start_paddr +
+ balloon_stats.hotplug_size);
+
+ for (i = 0; i < nr_pages; ++i, ++pfn)
+ frame_list[i] = pfn;
+
+ pfn -= nr_pages + 1;
+ goto populate_physmap;
+ }
+#endif
+
page = balloon_first_page();
for (i = 0; i < nr_pages; i++) {
BUG_ON(page == NULL);
@@ -219,6 +288,9 @@ static int increase_reservation(unsigned long nr_pages)
page = balloon_next_page(page);
}
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+populate_physmap:
+#endif
set_xen_guest_handle(reservation.extent_start, frame_list);
reservation.nr_extents = nr_pages;
rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);
@@ -226,17 +298,33 @@ static int increase_reservation(unsigned long nr_pages)
goto out;
for (i = 0; i < rc; i++) {
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ if (balloon_stats.hotplug_start_paddr) {
+ ++pfn;
+ goto set_p2m;
+ }
+#endif
+
page = balloon_retrieve();
BUG_ON(page == NULL);
pfn = page_to_pfn(page);
+
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+set_p2m:
+#endif
BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) &&
phys_to_machine_mapping_valid(pfn));
set_phys_to_machine(pfn, frame_list[i]);
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ if (balloon_stats.hotplug_start_paddr)
+ continue;
+#endif
+
/* Link back into the page tables if not highmem. */
- if (pfn < max_low_pfn) {
+ if (!PageHighMem(page)) {
int ret;
ret = HYPERVISOR_update_va_mapping(
(unsigned long)__va(pfn << PAGE_SHIFT),
@@ -251,6 +339,11 @@ static int increase_reservation(unsigned long nr_pages)
__free_page(page);
}
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ if (balloon_stats.hotplug_start_paddr)
+ balloon_stats.hotplug_size += rc << PAGE_SHIFT;
+#endif
+
balloon_stats.current_pages += rc;
out:
@@ -331,6 +424,12 @@ static void balloon_process(struct work_struct *work)
int need_sleep = 0;
long credit;
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ int nid, ret;
+ struct memory_block *mem;
+ unsigned long pfn, pfn_limit;
+#endif
+
mutex_lock(&balloon_mutex);
do {
@@ -349,10 +448,93 @@ static void balloon_process(struct work_struct *work)
/* Schedule more work if there is some still to be done. */
if (current_target() != balloon_stats.current_pages)
mod_timer(&balloon_timer, jiffies + HZ);
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ else if (balloon_stats.hotplug_start_paddr) {
+ nid = memory_add_physaddr_to_nid(balloon_stats.hotplug_start_paddr);
+
+ ret = xen_add_memory(nid, balloon_stats.hotplug_start_paddr,
+ balloon_stats.hotplug_size);
+
+ if (ret) {
+ printk(KERN_ERR "%s: xen_add_memory: "
+ "Memory hotplug failed: %i\n",
+ __func__, ret);
+ goto error;
+ }
+
+ pfn = PFN_DOWN(balloon_stats.hotplug_start_paddr);
+ pfn_limit = pfn + (balloon_stats.hotplug_size >> PAGE_SHIFT);
+
+ for (; pfn < pfn_limit; ++pfn)
+ if (!PageHighMem(pfn_to_page(pfn)))
+ BUG_ON(HYPERVISOR_update_va_mapping(
+ (unsigned long)__va(pfn << PAGE_SHIFT),
+ mfn_pte(pfn_to_mfn(pfn), PAGE_KERNEL), 0));
+
+ ret = online_pages(PFN_DOWN(balloon_stats.hotplug_start_paddr),
+ balloon_stats.hotplug_size >> PAGE_SHIFT);
+
+ if (ret) {
+ printk(KERN_ERR "%s: online_pages: Failed: %i\n",
+ __func__, ret);
+ goto error;
+ }
+
+ pfn = PFN_DOWN(balloon_stats.hotplug_start_paddr);
+ pfn_limit = pfn + (balloon_stats.hotplug_size >> PAGE_SHIFT);
+
+ for (; pfn < pfn_limit; pfn += PAGES_PER_SECTION) {
+ mem = find_memory_block(__pfn_to_section(pfn));
+ BUG_ON(!mem);
+ BUG_ON(!present_section_nr(mem->phys_index));
+ mutex_lock(&mem->state_mutex);
+ mem->state = MEM_ONLINE;
+ mutex_unlock(&mem->state_mutex);
+ }
+
+ goto out;
+
+error:
+ balloon_stats.current_pages -= balloon_stats.hotplug_size >> PAGE_SHIFT;
+ balloon_stats.target_pages -= balloon_stats.hotplug_size >> PAGE_SHIFT;
+
+out:
+ balloon_stats.hotplug_start_paddr = 0;
+ balloon_stats.hotplug_size = 0;
+ }
+#endif
mutex_unlock(&balloon_mutex);
}
+#ifdef CONFIG_XEN_MEMORY_HOTPLUG
+
+/* Resets the Xen limit, sets new target, and kicks off processing. */
+static void balloon_set_new_target(unsigned long target)
+{
+ mutex_lock(&balloon_mutex);
+ balloon_stats.target_pages = target;
+ mutex_unlock(&balloon_mutex);
+
+ schedule_work(&balloon_worker);
+}
+
+void balloon_update_stats(long nr_pages)
+{
+ mutex_lock(&balloon_mutex);
+
+ balloon_stats.current_pages += nr_pages;
+ balloon_stats.target_pages += nr_pages;
+
+ xenbus_printf(XBT_NIL, "memory", "target", "%llu",
+ (unsigned long long)balloon_stats.target_pages << (PAGE_SHIFT - 10));
+
+ mutex_unlock(&balloon_mutex);
+}
+EXPORT_SYMBOL_GPL(balloon_update_stats);
+
+#else
+
/* Resets the Xen limit, sets new target, and kicks off processing. */
static void balloon_set_new_target(unsigned long target)
{
@@ -361,6 +543,8 @@ static void balloon_set_new_target(unsigned long target)
schedule_work(&balloon_worker);
}
+#endif
+
static struct xenbus_watch target_watch =
{
.node = "memory/target"
@@ -416,6 +600,12 @@ static int __init balloon_init(void)
balloon_stats.balloon_high = 0;
balloon_stats.driver_pages = 0UL;
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ balloon_stats.boot_max_pfn = max_pfn;
+ balloon_stats.hotplug_start_paddr = 0;
+ balloon_stats.hotplug_size = 0;
+#endif
+
init_timer(&balloon_timer);
balloon_timer.data = 0;
balloon_timer.function = balloon_alarm;
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 35b07b7..04e67b8 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -211,4 +211,12 @@ extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
unsigned long pnum);
+#if defined(CONFIG_XEN_MEMORY_HOTPLUG) || defined(CONFIG_XEN_BALLOON_MEMORY_HOTPLUG)
+extern int xen_add_memory(int nid, u64 start, u64 size);
+#endif
+
+#ifdef CONFIG_XEN_MEMORY_HOTPLUG
+extern int xen_memory_probe(u64 phys_addr);
+#endif
+
#endif /* __LINUX_MEMORY_HOTPLUG_H */
diff --git a/include/xen/balloon.h b/include/xen/balloon.h
new file mode 100644
index 0000000..84b17b7
--- /dev/null
+++ b/include/xen/balloon.h
@@ -0,0 +1,6 @@
+#ifndef _XEN_BALLOON_H
+#define _XEN_BALLOON_H
+
+extern void balloon_update_stats(long nr_pages);
+
+#endif /* _XEN_BALLOON_H */
diff --git a/mm/Kconfig b/mm/Kconfig
index 9c61158..b04f3a8 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -144,6 +144,15 @@ config MEMORY_HOTREMOVE
depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
depends on MIGRATION
+config XEN_MEMORY_HOTPLUG
+ bool "Allow for memory hot-add in Xen guests"
+ depends on EXPERIMENTAL && ARCH_MEMORY_PROBE && XEN
+ default n
+ help
+ Memory hotplug allows expanding memory available for the system
+ above limit declared at system startup. It is very useful on critical
+ systems which require long run without rebooting.
+
#
# If we have space for more page flags then we can enable additional
# optimizations and functionality.
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index be211a5..1c73703 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -32,6 +32,14 @@
#include <asm/tlbflush.h>
+#ifdef CONFIG_XEN_MEMORY_HOTPLUG
+#include <asm/xen/hypercall.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/memory.h>
+#include <xen/features.h>
+#include <xen/page.h>
+#endif
+
#include "internal.h"
/* add this memory to iomem resource */
@@ -542,6 +550,138 @@ out:
}
EXPORT_SYMBOL_GPL(add_memory);
+#if defined(CONFIG_XEN_MEMORY_HOTPLUG) || defined(CONFIG_XEN_BALLOON_MEMORY_HOTPLUG)
+/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
+int __ref xen_add_memory(int nid, u64 start, u64 size)
+{
+ pg_data_t *pgdat = NULL;
+ int new_pgdat = 0, ret;
+
+ lock_system_sleep();
+
+ if (!node_online(nid)) {
+ pgdat = hotadd_new_pgdat(nid, start);
+ ret = -ENOMEM;
+ if (!pgdat)
+ goto out;
+ new_pgdat = 1;
+ }
+
+ /* call arch's memory hotadd */
+ ret = arch_add_memory(nid, start, size);
+
+ if (ret < 0)
+ goto error;
+
+ /* we online node here. we can't roll back from here. */
+ node_set_online(nid);
+
+ if (new_pgdat) {
+ ret = register_one_node(nid);
+ /*
+ * If sysfs file of new node can't create, cpu on the node
+ * can't be hot-added. There is no rollback way now.
+ * So, check by BUG_ON() to catch it reluctantly..
+ */
+ BUG_ON(ret);
+ }
+
+ goto out;
+
+error:
+ /* rollback pgdat allocation */
+ if (new_pgdat)
+ rollback_node_hotadd(nid, pgdat);
+
+out:
+ unlock_system_sleep();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(xen_add_memory);
+#endif
+
+#ifdef CONFIG_XEN_MEMORY_HOTPLUG
+int xen_memory_probe(u64 phys_addr)
+{
+ int nr_pages, ret;
+ struct resource *r;
+ struct xen_memory_reservation reservation = {
+ .address_bits = 0,
+ .extent_order = 0,
+ .domid = DOMID_SELF,
+ .nr_extents = PAGES_PER_SECTION
+ };
+ unsigned long *frame_list, i, pfn;
+
+ r = register_memory_resource(phys_addr, PAGES_PER_SECTION << PAGE_SHIFT);
+
+ if (!r)
+ return -EEXIST;
+
+ frame_list = vmalloc(PAGES_PER_SECTION * sizeof(unsigned long));
+
+ if (!frame_list) {
+ printk(KERN_ERR "%s: vmalloc: Out of memory\n", __func__);
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ set_xen_guest_handle(reservation.extent_start, frame_list);
+ for (i = 0, pfn = PFN_DOWN(phys_addr); i < PAGES_PER_SECTION; ++i, ++pfn)
+ frame_list[i] = pfn;
+
+ ret = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);
+
+ if (ret < PAGES_PER_SECTION) {
+ if (ret > 0) {
+ printk(KERN_ERR "%s: PHYSMAP is not fully "
+ "populated: %i/%lu\n", __func__,
+ ret, PAGES_PER_SECTION);
+ reservation.nr_extents = nr_pages = ret;
+ ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);
+ BUG_ON(ret != nr_pages);
+ ret = -ENOMEM;
+ } else {
+ ret = (ret < 0) ? ret : -ENOMEM;
+ printk(KERN_ERR "%s: Can't populate PHYSMAP: %i\n", __func__, ret);
+ }
+ goto error;
+ }
+
+ for (i = 0, pfn = PFN_DOWN(phys_addr); i < PAGES_PER_SECTION; ++i, ++pfn) {
+ BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) &&
+ phys_to_machine_mapping_valid(pfn));
+ set_phys_to_machine(pfn, frame_list[i]);
+ }
+
+ ret = xen_add_memory(memory_add_physaddr_to_nid(phys_addr), phys_addr,
+ PAGES_PER_SECTION << PAGE_SHIFT);
+
+ if (ret) {
+ printk(KERN_ERR "%s: xen_add_memory: Memory hotplug "
+ "failed: %i\n", __func__, ret);
+ goto out;
+ }
+
+ for (i = 0, pfn = PFN_DOWN(phys_addr); i < PAGES_PER_SECTION; ++i, ++pfn)
+ if (!PageHighMem(pfn_to_page(pfn)))
+ BUG_ON(HYPERVISOR_update_va_mapping(
+ (unsigned long)__va(pfn << PAGE_SHIFT),
+ mfn_pte(frame_list[i], PAGE_KERNEL), 0));
+
+ goto out;
+
+error:
+ release_memory_resource(r);
+
+out:
+ vfree(frame_list);
+
+ return (ret < 0) ? ret : 0;
+}
+EXPORT_SYMBOL_GPL(xen_memory_probe);
+#endif
+
#ifdef CONFIG_MEMORY_HOTREMOVE
/*
* A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
Signed-off-by: Daniel Kiper <dkiper@xxxxxxxxxxxx>
---
arch/x86/Kconfig | 2 +-
drivers/base/memory.c | 23 +++++
drivers/xen/Kconfig | 10 ++
drivers/xen/balloon.c | 196 +++++++++++++++++++++++++++++++++++++++-
include/linux/memory_hotplug.h | 8 ++
include/xen/balloon.h | 6 ++
mm/Kconfig | 9 ++
mm/memory_hotplug.c | 140 ++++++++++++++++++++++++++++
8 files changed, 390 insertions(+), 4 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 9458685..38434da 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1273,7 +1273,7 @@ config ARCH_SELECT_MEMORY_MODEL
depends on ARCH_SPARSEMEM_ENABLE
config ARCH_MEMORY_PROBE
- def_bool X86_64
+ def_bool y
depends on MEMORY_HOTPLUG
config ILLEGAL_POINTER_VALUE
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 933442f..709457b 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -27,6 +27,14 @@
#include <asm/atomic.h>
#include <asm/uaccess.h>
+#ifdef CONFIG_XEN_MEMORY_HOTPLUG
+#include <xen/xen.h>
+#endif
+
+#if defined(CONFIG_XEN_MEMORY_HOTPLUG) && defined(CONFIG_XEN_BALLOON)
+#include <xen/balloon.h>
+#endif
+
#define MEMORY_CLASS_NAME "memory"
static struct sysdev_class memory_sysdev_class = {
@@ -215,6 +223,10 @@ memory_block_action(struct memory_block *mem, unsigned long action)
case MEM_ONLINE:
start_pfn = page_to_pfn(first_page);
ret = online_pages(start_pfn, PAGES_PER_SECTION);
+#if defined(CONFIG_XEN_MEMORY_HOTPLUG) && defined(CONFIG_XEN_BALLOON)
+ if (xen_domain() && !ret)
+ balloon_update_stats(PAGES_PER_SECTION);
+#endif
break;
case MEM_OFFLINE:
mem->state = MEM_GOING_OFFLINE;
@@ -225,6 +237,10 @@ memory_block_action(struct memory_block *mem, unsigned long action)
mem->state = old_state;
break;
}
+#if defined(CONFIG_XEN_MEMORY_HOTPLUG) && defined(CONFIG_XEN_BALLOON)
+ if (xen_domain())
+ balloon_update_stats(-PAGES_PER_SECTION);
+#endif
break;
default:
WARN(1, KERN_WARNING "%s(%p, %ld) unknown action: %ld\n",
@@ -341,6 +357,13 @@ memory_probe_store(struct class *class, struct class_attribute *attr,
phys_addr = simple_strtoull(buf, NULL, 0);
+#ifdef CONFIG_XEN_MEMORY_HOTPLUG
+ if (xen_domain()) {
+ ret = xen_memory_probe(phys_addr);
+ return ret ? ret : count;
+ }
+#endif
+
nid = memory_add_physaddr_to_nid(phys_addr);
ret = add_memory(nid, phys_addr, PAGES_PER_SECTION << PAGE_SHIFT);
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index fad3df2..9713048 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -9,6 +9,16 @@ config XEN_BALLOON
the system to expand the domain's memory allocation, or alternatively
return unneeded memory to the system.
+config XEN_BALLOON_MEMORY_HOTPLUG
+ bool "Xen memory balloon driver with memory hotplug support"
+ depends on EXPERIMENTAL && XEN_BALLOON && MEMORY_HOTPLUG
+ default n
+ help
+ Xen memory balloon driver with memory hotplug support allows expanding
+ memory available for the system above limit declared at system startup.
+ It is very useful on critical systems which require long run without
+ rebooting.
+
config XEN_SCRUB_PAGES
bool "Scrub pages before returning them to system"
depends on XEN_BALLOON
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 1a0d8c2..f80bba0 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -6,6 +6,7 @@
* Copyright (c) 2003, B Dragovic
* Copyright (c) 2003-2004, M Williamson, K Fraser
* Copyright (c) 2005 Dan M. Smith, IBM Corporation
+ * Copyright (c) 2010 Daniel Kiper
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
@@ -61,6 +62,10 @@
#include <xen/features.h>
#include <xen/page.h>
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+#include <linux/memory.h>
+#endif
+
#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
#define BALLOON_CLASS_NAME "xen_memory"
@@ -77,6 +82,11 @@ struct balloon_stats {
/* Number of pages in high- and low-memory balloons. */
unsigned long balloon_low;
unsigned long balloon_high;
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ unsigned long boot_max_pfn;
+ u64 hotplug_start_paddr;
+ u64 hotplug_size;
+#endif
};
static DEFINE_MUTEX(balloon_mutex);
@@ -184,6 +194,12 @@ static void balloon_alarm(unsigned long unused)
schedule_work(&balloon_worker);
}
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+static inline unsigned long current_target(void)
+{
+ return balloon_stats.target_pages;
+}
+#else
static unsigned long current_target(void)
{
unsigned long target = balloon_stats.target_pages;
@@ -195,11 +211,12 @@ static unsigned long current_target(void)
return target;
}
+#endif
static int increase_reservation(unsigned long nr_pages)
{
- unsigned long pfn, i, flags;
- struct page *page;
+ unsigned long uninitialized_var(pfn), i, flags;
+ struct page *uninitialized_var(page);
long rc;
struct xen_memory_reservation reservation = {
.address_bits = 0,
@@ -207,11 +224,63 @@ static int increase_reservation(unsigned long nr_pages)
.domid = DOMID_SELF
};
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ resource_size_t r_min, r_size;
+ struct resource *r;
+#endif
+
if (nr_pages > ARRAY_SIZE(frame_list))
nr_pages = ARRAY_SIZE(frame_list);
spin_lock_irqsave(&balloon_lock, flags);
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ if (!balloon_stats.balloon_low && !balloon_stats.balloon_high) {
+ if (!balloon_stats.hotplug_start_paddr) {
+
+ /*
+ * Look for first unused memory region starting
+ * at page boundary. Skip last memory section created
+ * at boot time becuase it may contains unused memory
+ * pages with PG_reserved bit not set (online_pages
+ * require PG_reserved bit set).
+ */
+
+ r = kzalloc(sizeof(struct resource), GFP_KERNEL);
+
+ if (!r) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ r->name = "System RAM";
+ r->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+ r_min = PFN_PHYS(section_nr_to_pfn(pfn_to_section_nr(balloon_stats.boot_max_pfn) + 1));
+ r_size = (balloon_stats.target_pages - balloon_stats.current_pages) << PAGE_SHIFT;
+
+ rc = allocate_resource(&iomem_resource, r,
+ r_size, r_min, ULONG_MAX,
+ PAGE_SIZE, NULL, NULL);
+
+ if (rc < 0) {
+ kfree(r);
+ goto out;
+ }
+
+ balloon_stats.hotplug_start_paddr = r->start;
+ }
+
+ pfn = PFN_DOWN(balloon_stats.hotplug_start_paddr +
+ balloon_stats.hotplug_size);
+
+ for (i = 0; i < nr_pages; ++i, ++pfn)
+ frame_list[i] = pfn;
+
+ pfn -= nr_pages + 1;
+ goto populate_physmap;
+ }
+#endif
+
page = balloon_first_page();
for (i = 0; i < nr_pages; i++) {
BUG_ON(page == NULL);
@@ -219,6 +288,9 @@ static int increase_reservation(unsigned long nr_pages)
page = balloon_next_page(page);
}
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+populate_physmap:
+#endif
set_xen_guest_handle(reservation.extent_start, frame_list);
reservation.nr_extents = nr_pages;
rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);
@@ -226,17 +298,33 @@ static int increase_reservation(unsigned long nr_pages)
goto out;
for (i = 0; i < rc; i++) {
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ if (balloon_stats.hotplug_start_paddr) {
+ ++pfn;
+ goto set_p2m;
+ }
+#endif
+
page = balloon_retrieve();
BUG_ON(page == NULL);
pfn = page_to_pfn(page);
+
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+set_p2m:
+#endif
BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) &&
phys_to_machine_mapping_valid(pfn));
set_phys_to_machine(pfn, frame_list[i]);
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ if (balloon_stats.hotplug_start_paddr)
+ continue;
+#endif
+
/* Link back into the page tables if not highmem. */
- if (pfn < max_low_pfn) {
+ if (!PageHighMem(page)) {
int ret;
ret = HYPERVISOR_update_va_mapping(
(unsigned long)__va(pfn << PAGE_SHIFT),
@@ -251,6 +339,11 @@ static int increase_reservation(unsigned long nr_pages)
__free_page(page);
}
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ if (balloon_stats.hotplug_start_paddr)
+ balloon_stats.hotplug_size += rc << PAGE_SHIFT;
+#endif
+
balloon_stats.current_pages += rc;
out:
@@ -331,6 +424,12 @@ static void balloon_process(struct work_struct *work)
int need_sleep = 0;
long credit;
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ int nid, ret;
+ struct memory_block *mem;
+ unsigned long pfn, pfn_limit;
+#endif
+
mutex_lock(&balloon_mutex);
do {
@@ -349,10 +448,93 @@ static void balloon_process(struct work_struct *work)
/* Schedule more work if there is some still to be done. */
if (current_target() != balloon_stats.current_pages)
mod_timer(&balloon_timer, jiffies + HZ);
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ else if (balloon_stats.hotplug_start_paddr) {
+ nid = memory_add_physaddr_to_nid(balloon_stats.hotplug_start_paddr);
+
+ ret = xen_add_memory(nid, balloon_stats.hotplug_start_paddr,
+ balloon_stats.hotplug_size);
+
+ if (ret) {
+ printk(KERN_ERR "%s: xen_add_memory: "
+ "Memory hotplug failed: %i\n",
+ __func__, ret);
+ goto error;
+ }
+
+ pfn = PFN_DOWN(balloon_stats.hotplug_start_paddr);
+ pfn_limit = pfn + (balloon_stats.hotplug_size >> PAGE_SHIFT);
+
+ for (; pfn < pfn_limit; ++pfn)
+ if (!PageHighMem(pfn_to_page(pfn)))
+ BUG_ON(HYPERVISOR_update_va_mapping(
+ (unsigned long)__va(pfn << PAGE_SHIFT),
+ mfn_pte(pfn_to_mfn(pfn), PAGE_KERNEL), 0));
+
+ ret = online_pages(PFN_DOWN(balloon_stats.hotplug_start_paddr),
+ balloon_stats.hotplug_size >> PAGE_SHIFT);
+
+ if (ret) {
+ printk(KERN_ERR "%s: online_pages: Failed: %i\n",
+ __func__, ret);
+ goto error;
+ }
+
+ pfn = PFN_DOWN(balloon_stats.hotplug_start_paddr);
+ pfn_limit = pfn + (balloon_stats.hotplug_size >> PAGE_SHIFT);
+
+ for (; pfn < pfn_limit; pfn += PAGES_PER_SECTION) {
+ mem = find_memory_block(__pfn_to_section(pfn));
+ BUG_ON(!mem);
+ BUG_ON(!present_section_nr(mem->phys_index));
+ mutex_lock(&mem->state_mutex);
+ mem->state = MEM_ONLINE;
+ mutex_unlock(&mem->state_mutex);
+ }
+
+ goto out;
+
+error:
+ balloon_stats.current_pages -= balloon_stats.hotplug_size >> PAGE_SHIFT;
+ balloon_stats.target_pages -= balloon_stats.hotplug_size >> PAGE_SHIFT;
+
+out:
+ balloon_stats.hotplug_start_paddr = 0;
+ balloon_stats.hotplug_size = 0;
+ }
+#endif
mutex_unlock(&balloon_mutex);
}
+#ifdef CONFIG_XEN_MEMORY_HOTPLUG
+
+/* Resets the Xen limit, sets new target, and kicks off processing. */
+static void balloon_set_new_target(unsigned long target)
+{
+ mutex_lock(&balloon_mutex);
+ balloon_stats.target_pages = target;
+ mutex_unlock(&balloon_mutex);
+
+ schedule_work(&balloon_worker);
+}
+
+void balloon_update_stats(long nr_pages)
+{
+ mutex_lock(&balloon_mutex);
+
+ balloon_stats.current_pages += nr_pages;
+ balloon_stats.target_pages += nr_pages;
+
+ xenbus_printf(XBT_NIL, "memory", "target", "%llu",
+ (unsigned long long)balloon_stats.target_pages << (PAGE_SHIFT - 10));
+
+ mutex_unlock(&balloon_mutex);
+}
+EXPORT_SYMBOL_GPL(balloon_update_stats);
+
+#else
+
/* Resets the Xen limit, sets new target, and kicks off processing. */
static void balloon_set_new_target(unsigned long target)
{
@@ -361,6 +543,8 @@ static void balloon_set_new_target(unsigned long target)
schedule_work(&balloon_worker);
}
+#endif
+
static struct xenbus_watch target_watch =
{
.node = "memory/target"
@@ -416,6 +600,12 @@ static int __init balloon_init(void)
balloon_stats.balloon_high = 0;
balloon_stats.driver_pages = 0UL;
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ balloon_stats.boot_max_pfn = max_pfn;
+ balloon_stats.hotplug_start_paddr = 0;
+ balloon_stats.hotplug_size = 0;
+#endif
+
init_timer(&balloon_timer);
balloon_timer.data = 0;
balloon_timer.function = balloon_alarm;
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 35b07b7..04e67b8 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -211,4 +211,12 @@ extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
unsigned long pnum);
+#if defined(CONFIG_XEN_MEMORY_HOTPLUG) || defined(CONFIG_XEN_BALLOON_MEMORY_HOTPLUG)
+extern int xen_add_memory(int nid, u64 start, u64 size);
+#endif
+
+#ifdef CONFIG_XEN_MEMORY_HOTPLUG
+extern int xen_memory_probe(u64 phys_addr);
+#endif
+
#endif /* __LINUX_MEMORY_HOTPLUG_H */
diff --git a/include/xen/balloon.h b/include/xen/balloon.h
new file mode 100644
index 0000000..84b17b7
--- /dev/null
+++ b/include/xen/balloon.h
@@ -0,0 +1,6 @@
+#ifndef _XEN_BALLOON_H
+#define _XEN_BALLOON_H
+
+extern void balloon_update_stats(long nr_pages);
+
+#endif /* _XEN_BALLOON_H */
diff --git a/mm/Kconfig b/mm/Kconfig
index 9c61158..b04f3a8 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -144,6 +144,15 @@ config MEMORY_HOTREMOVE
depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
depends on MIGRATION
+config XEN_MEMORY_HOTPLUG
+ bool "Allow for memory hot-add in Xen guests"
+ depends on EXPERIMENTAL && ARCH_MEMORY_PROBE && XEN
+ default n
+ help
+ Memory hotplug allows expanding memory available for the system
+ above limit declared at system startup. It is very useful on critical
+ systems which require long run without rebooting.
+
#
# If we have space for more page flags then we can enable additional
# optimizations and functionality.
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index be211a5..1c73703 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -32,6 +32,14 @@
#include <asm/tlbflush.h>
+#ifdef CONFIG_XEN_MEMORY_HOTPLUG
+#include <asm/xen/hypercall.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/memory.h>
+#include <xen/features.h>
+#include <xen/page.h>
+#endif
+
#include "internal.h"
/* add this memory to iomem resource */
@@ -542,6 +550,138 @@ out:
}
EXPORT_SYMBOL_GPL(add_memory);
+#if defined(CONFIG_XEN_MEMORY_HOTPLUG) || defined(CONFIG_XEN_BALLOON_MEMORY_HOTPLUG)
+/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
+int __ref xen_add_memory(int nid, u64 start, u64 size)
+{
+ pg_data_t *pgdat = NULL;
+ int new_pgdat = 0, ret;
+
+ lock_system_sleep();
+
+ if (!node_online(nid)) {
+ pgdat = hotadd_new_pgdat(nid, start);
+ ret = -ENOMEM;
+ if (!pgdat)
+ goto out;
+ new_pgdat = 1;
+ }
+
+ /* call arch's memory hotadd */
+ ret = arch_add_memory(nid, start, size);
+
+ if (ret < 0)
+ goto error;
+
+ /* we online node here. we can't roll back from here. */
+ node_set_online(nid);
+
+ if (new_pgdat) {
+ ret = register_one_node(nid);
+ /*
+ * If sysfs file of new node can't create, cpu on the node
+ * can't be hot-added. There is no rollback way now.
+ * So, check by BUG_ON() to catch it reluctantly..
+ */
+ BUG_ON(ret);
+ }
+
+ goto out;
+
+error:
+ /* rollback pgdat allocation */
+ if (new_pgdat)
+ rollback_node_hotadd(nid, pgdat);
+
+out:
+ unlock_system_sleep();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(xen_add_memory);
+#endif
+
+#ifdef CONFIG_XEN_MEMORY_HOTPLUG
+int xen_memory_probe(u64 phys_addr)
+{
+ int nr_pages, ret;
+ struct resource *r;
+ struct xen_memory_reservation reservation = {
+ .address_bits = 0,
+ .extent_order = 0,
+ .domid = DOMID_SELF,
+ .nr_extents = PAGES_PER_SECTION
+ };
+ unsigned long *frame_list, i, pfn;
+
+ r = register_memory_resource(phys_addr, PAGES_PER_SECTION << PAGE_SHIFT);
+
+ if (!r)
+ return -EEXIST;
+
+ frame_list = vmalloc(PAGES_PER_SECTION * sizeof(unsigned long));
+
+ if (!frame_list) {
+ printk(KERN_ERR "%s: vmalloc: Out of memory\n", __func__);
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ set_xen_guest_handle(reservation.extent_start, frame_list);
+ for (i = 0, pfn = PFN_DOWN(phys_addr); i < PAGES_PER_SECTION; ++i, ++pfn)
+ frame_list[i] = pfn;
+
+ ret = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);
+
+ if (ret < PAGES_PER_SECTION) {
+ if (ret > 0) {
+ printk(KERN_ERR "%s: PHYSMAP is not fully "
+ "populated: %i/%lu\n", __func__,
+ ret, PAGES_PER_SECTION);
+ reservation.nr_extents = nr_pages = ret;
+ ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);
+ BUG_ON(ret != nr_pages);
+ ret = -ENOMEM;
+ } else {
+ ret = (ret < 0) ? ret : -ENOMEM;
+ printk(KERN_ERR "%s: Can't populate PHYSMAP: %i\n", __func__, ret);
+ }
+ goto error;
+ }
+
+ for (i = 0, pfn = PFN_DOWN(phys_addr); i < PAGES_PER_SECTION; ++i, ++pfn) {
+ BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) &&
+ phys_to_machine_mapping_valid(pfn));
+ set_phys_to_machine(pfn, frame_list[i]);
+ }
+
+ ret = xen_add_memory(memory_add_physaddr_to_nid(phys_addr), phys_addr,
+ PAGES_PER_SECTION << PAGE_SHIFT);
+
+ if (ret) {
+ printk(KERN_ERR "%s: xen_add_memory: Memory hotplug "
+ "failed: %i\n", __func__, ret);
+ goto out;
+ }
+
+ for (i = 0, pfn = PFN_DOWN(phys_addr); i < PAGES_PER_SECTION; ++i, ++pfn)
+ if (!PageHighMem(pfn_to_page(pfn)))
+ BUG_ON(HYPERVISOR_update_va_mapping(
+ (unsigned long)__va(pfn << PAGE_SHIFT),
+ mfn_pte(frame_list[i], PAGE_KERNEL), 0));
+
+ goto out;
+
+error:
+ release_memory_resource(r);
+
+out:
+ vfree(frame_list);
+
+ return (ret < 0) ? ret : 0;
+}
+EXPORT_SYMBOL_GPL(xen_memory_probe);
+#endif
+
#ifdef CONFIG_MEMORY_HOTREMOVE
/*
* A free page on the buddy free lists (not the per-cpu lists) has PageBuddy