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[Xen-devel] [PATCH] GSoC 2010 - Memory hotplug support for Xen guests - fully working version



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

Attachment: linux-2.6.34.1-xen-memory-hotplug.r0.patch
Description: Text document

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