Features and fixes:
- new version of memory hotplug patch which supports
among others memory allocation policies during errors
(try until success or stop at first error),
- this version of patch was tested with tmem
(selfballooning and frontswap) and works
very well with it,
- some other minor fixes.
Signed-off-by: Daniel Kiper <dkiper@xxxxxxxxxxxx>
---
drivers/xen/Kconfig | 10 ++
drivers/xen/balloon.c | 231 ++++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 230 insertions(+), 11 deletions(-)
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 07bec09..8f880aa 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 "Memory hotplug support for Xen balloon driver"
+ default n
+ depends on XEN_BALLOON && MEMORY_HOTPLUG
+ help
+ Memory hotplug support for Xen balloon driver 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 b1e199c..e43e928 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -6,6 +6,12 @@
* 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
+ *
+ * Memory hotplug support was written by Daniel Kiper. Work on
+ * it was sponsored by Google under Google Summer of Code 2010
+ * program. Jeremy Fitzhardinge from Xen.org was the mentor for
+ * this project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
@@ -44,6 +50,7 @@
#include <linux/list.h>
#include <linux/sysdev.h>
#include <linux/gfp.h>
+#include <linux/memory.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
@@ -80,6 +87,9 @@ enum bp_state {
BP_HUNGRY
};
+#define MH_POLICY_TRY_UNTIL_SUCCESS 0
+#define MH_POLICY_STOP_AT_FIRST_ERROR 1
+
struct balloon_stats {
/* We aim for 'current allocation' == 'target allocation'. */
unsigned long current_pages;
@@ -89,6 +99,10 @@ struct balloon_stats {
unsigned long balloon_high;
unsigned long schedule_delay;
unsigned long max_schedule_delay;
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ unsigned long boot_max_pfn;
+ unsigned long mh_policy;
+#endif
};
static DEFINE_MUTEX(balloon_mutex);
@@ -206,18 +220,199 @@ static void update_schedule_delay(enum bp_state state)
balloon_stats.schedule_delay = new_schedule_delay;
}
-static unsigned long current_target(void)
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+static struct resource *allocate_memory_resource(unsigned long nr_pages)
+{
+ resource_size_t r_min, r_size;
+ struct resource *r;
+
+ /*
+ * Look for first unused memory region starting at page
+ * boundary. Skip last memory section created at boot time
+ * because 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)
+ return NULL;
+
+ 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 = nr_pages << PAGE_SHIFT;
+
+ if (allocate_resource(&iomem_resource, r, r_size, r_min,
+ ULONG_MAX, PAGE_SIZE, NULL, NULL) < 0) {
+ kfree(r);
+ return NULL;
+ }
+
+ return r;
+}
+
+static struct resource *adjust_memory_resource(struct resource *r, unsigned
long nr_pages)
+{
+ int rc;
+
+ if (r->end + 1 - (nr_pages << PAGE_SHIFT) == r->start) {
+ rc = release_resource(r);
+ BUG_ON(rc < 0);
+ kfree(r);
+ return NULL;
+ }
+
+ rc = adjust_resource(r, r->start, r->end + 1 - r->start -
+ (nr_pages << PAGE_SHIFT));
+
+ BUG_ON(rc < 0);
+
+ return r;
+}
+
+static int allocate_additional_memory(struct resource *r, unsigned long
nr_pages)
+{
+ int rc;
+ struct xen_memory_reservation reservation = {
+ .address_bits = 0,
+ .extent_order = 0,
+ .domid = DOMID_SELF
+ };
+ unsigned long flags, i, pfn, pfn_start;
+
+ if (!nr_pages)
+ return 0;
+
+ pfn_start = PFN_UP(r->end) - nr_pages;
+
+ if (nr_pages > ARRAY_SIZE(frame_list))
+ nr_pages = ARRAY_SIZE(frame_list);
+
+ for (i = 0, pfn = pfn_start; i < nr_pages; ++i, ++pfn)
+ frame_list[i] = pfn;
+
+ set_xen_guest_handle(reservation.extent_start, frame_list);
+ reservation.nr_extents = nr_pages;
+
+ spin_lock_irqsave(&xen_reservation_lock, flags);
+
+ rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);
+
+ if (rc <= 0)
+ return (rc < 0) ? rc : -ENOMEM;
+
+ for (i = 0, pfn = pfn_start; i < rc; ++i, ++pfn) {
+ BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) &&
+ phys_to_machine_mapping_valid(pfn));
+ set_phys_to_machine(pfn, frame_list[i]);
+ }
+
+ spin_unlock_irqrestore(&xen_reservation_lock, flags);
+
+ return rc;
+}
+
+static void hotplug_allocated_memory(struct resource *r)
{
- unsigned long target = balloon_stats.target_pages;
+ int nid, rc;
+ resource_size_t r_size;
+ struct memory_block *mem;
+ unsigned long pfn;
+
+ r_size = r->end + 1 - r->start;
+ nid = memory_add_physaddr_to_nid(r->start);
+
+ rc = add_registered_memory(nid, r->start, r_size);
+
+ if (rc) {
+ pr_err("%s: add_registered_memory: Memory hotplug failed: %i\n",
+ __func__, rc);
+ balloon_stats.target_pages = balloon_stats.current_pages;
+ return;
+ }
+
+ if (xen_pv_domain())
+ for (pfn = PFN_DOWN(r->start); pfn < PFN_UP(r->end); ++pfn)
+ if (!PageHighMem(pfn_to_page(pfn))) {
+ rc = HYPERVISOR_update_va_mapping(
+ (unsigned long)__va(pfn << PAGE_SHIFT),
+ mfn_pte(pfn_to_mfn(pfn), PAGE_KERNEL),
0);
+ BUG_ON(rc);
+ }
- target = min(target,
- balloon_stats.current_pages +
- balloon_stats.balloon_low +
- balloon_stats.balloon_high);
+ rc = online_pages(PFN_DOWN(r->start), r_size >> PAGE_SHIFT);
- return target;
+ if (rc) {
+ pr_err("%s: online_pages: Failed: %i\n", __func__, rc);
+ balloon_stats.target_pages = balloon_stats.current_pages;
+ return;
+ }
+
+ for (pfn = PFN_DOWN(r->start); pfn < PFN_UP(r->end); 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);
+ }
+
+ balloon_stats.current_pages += r_size >> PAGE_SHIFT;
}
+static enum bp_state request_additional_memory(long credit)
+{
+ int rc;
+ static struct resource *r;
+ static unsigned long pages_left;
+
+ if ((credit <= 0 || balloon_stats.balloon_low ||
+ balloon_stats.balloon_high) && !r)
+ return BP_DONE;
+
+ if (!r) {
+ r = allocate_memory_resource(credit);
+
+ if (!r)
+ return BP_ERROR;
+
+ pages_left = credit;
+ }
+
+ rc = allocate_additional_memory(r, pages_left);
+
+ if (rc < 0) {
+ if (balloon_stats.mh_policy == MH_POLICY_TRY_UNTIL_SUCCESS)
+ return BP_ERROR;
+
+ r = adjust_memory_resource(r, pages_left);
+
+ if (!r)
+ return BP_ERROR;
+ } else {
+ pages_left -= rc;
+
+ if (pages_left)
+ return BP_HUNGRY;
+ }
+
+ hotplug_allocated_memory(r);
+
+ r = NULL;
+
+ return BP_DONE;
+}
+#else
+static enum bp_state request_additional_memory(long credit)
+{
+ if (balloon_stats.balloon_low && balloon_stats.balloon_high &&
+ balloon_stats.target_pages >
balloon_stats.current_pages)
+ balloon_stats.target_pages = balloon_stats.current_pages;
+ return BP_DONE;
+}
+#endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */
+
static enum bp_state increase_reservation(unsigned long nr_pages)
{
enum bp_state state = BP_DONE;
@@ -352,15 +547,17 @@ static enum bp_state decrease_reservation(unsigned long
nr_pages)
*/
static void balloon_process(struct work_struct *work)
{
- enum bp_state rc, state = BP_DONE;
+ enum bp_state rc, state;
long credit;
mutex_lock(&balloon_mutex);
do {
- credit = current_target() - balloon_stats.current_pages;
+ credit = balloon_stats.target_pages -
balloon_stats.current_pages;
- if (credit > 0) {
+ state = request_additional_memory(credit);
+
+ if (credit > 0 && state == BP_DONE) {
rc = increase_reservation(credit);
state = (rc == BP_ERROR) ? BP_ERROR : state;
}
@@ -450,6 +647,11 @@ static int __init balloon_init(void)
balloon_stats.schedule_delay = 1;
balloon_stats.max_schedule_delay = 32;
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ balloon_stats.boot_max_pfn = max_pfn;
+ balloon_stats.mh_policy = MH_POLICY_STOP_AT_FIRST_ERROR;
+#endif
+
register_balloon(&balloon_sysdev);
/*
@@ -506,6 +708,10 @@ BALLOON_SHOW(high_kb, "%lu\n",
PAGES2KB(balloon_stats.balloon_high));
static SYSDEV_ULONG_ATTR(schedule_delay, 0644, balloon_stats.schedule_delay);
static SYSDEV_ULONG_ATTR(max_schedule_delay, 0644,
balloon_stats.max_schedule_delay);
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+static SYSDEV_ULONG_ATTR(memory_hotplug_policy, 0644, balloon_stats.mh_policy);
+#endif
+
static ssize_t show_target_kb(struct sys_device *dev, struct sysdev_attribute
*attr,
char *buf)
{
@@ -568,7 +774,10 @@ static struct sysdev_attribute *balloon_attrs[] = {
&attr_target_kb,
&attr_target,
&attr_schedule_delay.attr,
- &attr_max_schedule_delay.attr
+ &attr_max_schedule_delay.attr,
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+ &attr_memory_hotplug_policy.attr
+#endif
};
static struct attribute *balloon_info_attrs[] = {
--
1.5.6.5
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