RE: [PATCH] VMware Balloon: rename module

RE: [PATCH] VMware Balloon: rename module

[Chetan Loke]

> From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-
> owner@vger.kernel.org] On Behalf Of Dmitry Torokhov
> Sent: September 16, 2010 6:01 PM
> To: linux-kernel@vger.kernel.org
> Cc: pv-drivers@vmware.com; Andrew Morton
> Subject: [PATCH] VMware Balloon: rename module
>


> In an effort to minimize customer confusion we want to unify naming
> convention for VMware-provided kernel modules. This change renames
> the balloon driver from vmware_ballon to vmw_balloon.
>
What will vmtools name its vmware_balloon driver to? vmw_balloon, correct?


> +	vmballoon_wq = create_freezeable_workqueue("vmmemctl");
minor change - vmware_vmmemctl?

I might've seen a debugfs entry too.


side note - is it possible to extend the balloon driver to get a
notification on other events? like CPUs, NICs? Just an event is what
I'm looking for. No action need to be taken in the guest.

regards
Chetan Loke

Re: [PATCH] VMware Balloon: rename module

[Dmitry Torokhov]

Hi Chetan,

On Thursday, September 16, 2010 04:05:28 pm Chetan Loke wrote:
> > From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-
> > owner@vger.kernel.org] On Behalf Of Dmitry Torokhov
> > Sent: September 16, 2010 6:01 PM
> > To: linux-kernel@vger.kernel.org
> > Cc: pv-drivers@vmware.com; Andrew Morton
> > Subject: [PATCH] VMware Balloon: rename module
> > 
> > 
> > 
> > In an effort to minimize customer confusion we want to unify naming
> > convention for VMware-provided kernel modules. This change renames
> > the balloon driver from vmware_ballon to vmw_balloon.
> 
> What will vmtools name its vmware_balloon driver to? vmw_balloon, correct?

That is the plan.

> 
> > +	vmballoon_wq = create_freezeable_workqueue("vmmemctl");
> 
> minor change - vmware_vmmemctl?

I do not think this needs to be changed; it does not have to match
the module name, plus, given Tejun's changes, it will all be generic
[worker/u:X] soon anyway.

> 
> I might've seen a debugfs entry too.

I still plan on keeping it as "vmmemctl" so we do not have to change
scripts too often. The move in module names prompted by complaints
that name changes when user requests tools to clobber distribution-
provided modules.

> 
> 
> side note - is it possible to extend the balloon driver to get a
> notification on other events? like CPUs, NICs? Just an event is what
> I'm looking for. No action need to be taken in the guest.

No, balloon driver should be limited to ballooning. I think the data
you are looking for can be retrieved via GuestSDK (and I believe we
are adding balloon_target to the available data).

Thanks.

-- 
Dmitry

Re: [PATCH] VMware Balloon: rename module

[Chetan Loke]

On Thu, Sep 16, 2010 at 7:23 PM, Dmitry Torokhov <dtor@vmware.com> wrote:
> Hi Chetan,
Hi

>> > In an effort to minimize customer confusion we want to unify naming
>> > convention for VMware-provided kernel modules. This change renames
>> > the balloon driver from vmware_ballon to vmw_balloon.
>>
>> What will vmtools name its vmware_balloon driver to? vmw_balloon, correct?
>
> That is the plan.

I will have to change my scripts/iso's if there's a mismatch. If
there's a mismatch then will we end up w/ 2 drivers?
Or will vmtools cleanup the past residue?
We prep'd a 2.6.35 iso. Now while updating I will have to wrap a
special case to account for balloon-renaming.
The case that I'm worried about is this:
1) 2.6.35 - vmware_balloon
2) upgrade kernel - now vmw_balloon
3) install vmtools  - a new vmware_balloon(?) if this version of
vmtools didn't pick up the change?
Is there a workaround?

Sorry, not being a pain but we have had some tough time with
vmtool-upgrades+udev+vmxnet and vnic addition/deletion recently.


>
>>
>> > +   vmballoon_wq = create_freezeable_workqueue("vmmemctl");
>>
>> minor change - vmware_vmmemctl?
>
> I do not think this needs to be changed; it does not have to match
> the module name, plus, given Tejun's changes, it will all be generic
> [worker/u:X] soon anyway.
>
ok.


>>
>> side note - is it possible to extend the balloon driver to get a
>> notification on other events? like CPUs, NICs? Just an event is what
>> I'm looking for. No action need to be taken in the guest.
>
> No, balloon driver should be limited to ballooning. I think the data
> you are looking for can be retrieved via GuestSDK (and I believe we
> are adding balloon_target to the available data).
>

No. I think the guestSDK provides the guest, it's personal view of the
world, no?
http://www.vmware.com/support/developer/guest-sdk/

ballooning is an indirect hint that an external event has happened
within the hypervisor. I'm looking for similar external events.
guestSDK gives nothing. Because right now there is now way for a
vmware-guest to cooperate or be a good citizen if it
doesn't know what's happening in the esx-hypervisor. Now whether to
add these events in the balloon driver is another thing.
A separate driver is ok too.

> Thanks.
> Dmitry

thanks
cloke

Re: [PATCH] VMware Balloon: rename module

[Dmitry Torokhov]

On Thursday, September 16, 2010 05:13:32 pm Chetan Loke wrote:
> On Thu, Sep 16, 2010 at 7:23 PM, Dmitry Torokhov <dtor@vmware.com> wrote:
> > Hi Chetan,
> 
> Hi
> 
> >> > In an effort to minimize customer confusion we want to unify naming
> >> > convention for VMware-provided kernel modules. This change renames
> >> > the balloon driver from vmware_ballon to vmw_balloon.
> >> 
> >> What will vmtools name its vmware_balloon driver to? vmw_balloon,
> >> correct?
> > 
> > That is the plan.
> 
> I will have to change my scripts/iso's if there's a mismatch. If
> there's a mismatch then will we end up w/ 2 drivers?
> Or will vmtools cleanup the past residue?

Tools should clean up residue - the "upgrade" is actually "ininstall
everything keeping certain configs and install afresh".

> We prep'd a 2.6.35 iso. Now while updating I will have to wrap a
> special case to account for balloon-renaming.
> The case that I'm worried about is this:
> 1) 2.6.35 - vmware_balloon
> 2) upgrade kernel - now vmw_balloon
> 3) install vmtools  - a new vmware_balloon(?) if this version of
> vmtools didn't pick up the change?

The newer tools should pick up the driver regardless of the name as we
are keying off module alias data (which is PCI_IDs for PCI drivers
such as vmxnet3 and vmw_pvscsi and "magic strings" like "vmware_vmmemctl"
for non-PCI drivers).

> Is there a workaround?
> 
> Sorry, not being a pain but we have had some tough time with
> vmtool-upgrades+udev+vmxnet and vnic addition/deletion recently.
> 
> >> > +   vmballoon_wq = create_freezeable_workqueue("vmmemctl");
> >> 
> >> minor change - vmware_vmmemctl?
> > 
> > I do not think this needs to be changed; it does not have to match
> > the module name, plus, given Tejun's changes, it will all be generic
> > [worker/u:X] soon anyway.
> 
> ok.
> 
> >> side note - is it possible to extend the balloon driver to get a
> >> notification on other events? like CPUs, NICs? Just an event is what
> >> I'm looking for. No action need to be taken in the guest.
> > 
> > No, balloon driver should be limited to ballooning. I think the data
> > you are looking for can be retrieved via GuestSDK (and I believe we
> > are adding balloon_target to the available data).
> 
> No. I think the guestSDK provides the guest, it's personal view of the
> world, no?
> http://www.vmware.com/support/developer/guest-sdk/

Right since guest is supposed to be isolated.

There is vSphere SDK that shoudl allow you to connect to the hostd and
get more information about the host/VC:

http://www.vmware.com/support/developer/viperltoolkit/


> 
> ballooning is an indirect hint that an external event has happened
> within the hypervisor. I'm looking for similar external events.
> guestSDK gives nothing. Because right now there is now way for a
> vmware-guest to cooperate or be a good citizen if it
> doesn't know what's happening in the esx-hypervisor. Now whether to
> add these events in the balloon driver is another thing.
> A separate driver is ok too.

I spoke with resource management team regarding this idea of a VM
"helping" ESX and they felt that this task is better left to the
ESX's memory scheduler. The VM in question will not know all the
data needed (it might be confined to a separate resource pool, etc)
to make good decision.

Still you could use Guest SDK - if you see balloon target rising you
may start unlocking memory you grabbed.

-- 
Dmitry

Re: [PATCH] VMware Balloon: rename module

[jbian]

Yeah,the vmware_balloon driver name changed,when the name is vmware_balloon,the
rhel6 guest on esxi5.1,when modprobe the balloon driver,there will be a
process"vmmemctl",after the driver upgrade:vmw_balloon,the rhel7 guest on
esxi5.1,the balloon is vmw_balloon,but the process daemon disappear,but the
balloon still worked well,so why remove the vmmemctl process??

Thanks in advance,I will be feel grateful to receive all your reply.

B.R
jbian

[PATCH] VMware Balloon: rename module

[Dmitry Torokhov]

In an effort to minimize customer confusion we want to unify naming
convention for VMware-provided kernel modules. This change renames
the balloon driver from vmware_ballon to vmw_balloon.

We expect to follow this naming convention (vmw_<module_name>) for
all modules that are part of mainline kernel and/or being distributed
by VMware, with the sole exception of vmxnet3 driver (since the name of
mainline driver happens to match with the name used in VMware Tools).

Acked-by: Bhavesh Davda <bhavesh@vmware.com>
Signed-off-by: Dmitry Torokhov <dtor@vmware.com>
---
 drivers/misc/Kconfig          |    2 +-
 drivers/misc/Makefile         |    2 +-
 drivers/misc/vmw_balloon.c    |  844 +++++++++++++++++++++++++++++++++++++++++
 drivers/misc/vmware_balloon.c |  844 -----------------------------------------
 4 files changed, 846 insertions(+), 846 deletions(-)
 create mode 100644 drivers/misc/vmw_balloon.c
 delete mode 100644 drivers/misc/vmware_balloon.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 26386a9..11d2253 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -351,7 +351,7 @@ config VMWARE_BALLOON
 	  If unsure, say N.
 
 	  To compile this driver as a module, choose M here: the
-	  module will be called vmware_balloon.
+	  module will be called vmw_balloon.
 
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 6ed06a1..35e2fe2 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -30,4 +30,4 @@ obj-$(CONFIG_C2PORT)		+= c2port/
 obj-$(CONFIG_IWMC3200TOP)      += iwmc3200top/
 obj-y				+= eeprom/
 obj-y				+= cb710/
-obj-$(CONFIG_VMWARE_BALLOON)	+= vmware_balloon.o
+obj-$(CONFIG_VMWARE_BALLOON)	+= vmw_balloon.o
diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
new file mode 100644
index 0000000..2a1e804
--- /dev/null
+++ b/drivers/misc/vmw_balloon.c
@@ -0,0 +1,844 @@
+/*
+ * VMware Balloon driver.
+ *
+ * Copyright (C) 2000-2010, VMware, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; version 2 of the License and no later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Maintained by: Dmitry Torokhov <dtor@vmware.com>
+ */
+
+/*
+ * This is VMware physical memory management driver for Linux. The driver
+ * acts like a "balloon" that can be inflated to reclaim physical pages by
+ * reserving them in the guest and invalidating them in the monitor,
+ * freeing up the underlying machine pages so they can be allocated to
+ * other guests.  The balloon can also be deflated to allow the guest to
+ * use more physical memory. Higher level policies can control the sizes
+ * of balloons in VMs in order to manage physical memory resources.
+ */
+
+//#define DEBUG
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/workqueue.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <asm/hypervisor.h>
+
+MODULE_AUTHOR("VMware, Inc.");
+MODULE_DESCRIPTION("VMware Memory Control (Balloon) Driver");
+MODULE_VERSION("1.2.1.1-k");
+MODULE_ALIAS("dmi:*:svnVMware*:*");
+MODULE_ALIAS("vmware_vmmemctl");
+MODULE_LICENSE("GPL");
+
+/*
+ * Various constants controlling rate of inflaint/deflating balloon,
+ * measured in pages.
+ */
+
+/*
+ * Rate of allocating memory when there is no memory pressure
+ * (driver performs non-sleeping allocations).
+ */
+#define VMW_BALLOON_NOSLEEP_ALLOC_MAX	16384U
+
+/*
+ * Rates of memory allocaton when guest experiences memory pressure
+ * (driver performs sleeping allocations).
+ */
+#define VMW_BALLOON_RATE_ALLOC_MIN	512U
+#define VMW_BALLOON_RATE_ALLOC_MAX	2048U
+#define VMW_BALLOON_RATE_ALLOC_INC	16U
+
+/*
+ * Rates for releasing pages while deflating balloon.
+ */
+#define VMW_BALLOON_RATE_FREE_MIN	512U
+#define VMW_BALLOON_RATE_FREE_MAX	16384U
+#define VMW_BALLOON_RATE_FREE_INC	16U
+
+/*
+ * When guest is under memory pressure, use a reduced page allocation
+ * rate for next several cycles.
+ */
+#define VMW_BALLOON_SLOW_CYCLES		4
+
+/*
+ * Use __GFP_HIGHMEM to allow pages from HIGHMEM zone. We don't
+ * allow wait (__GFP_WAIT) for NOSLEEP page allocations. Use
+ * __GFP_NOWARN, to suppress page allocation failure warnings.
+ */
+#define VMW_PAGE_ALLOC_NOSLEEP		(__GFP_HIGHMEM|__GFP_NOWARN)
+
+/*
+ * Use GFP_HIGHUSER when executing in a separate kernel thread
+ * context and allocation can sleep.  This is less stressful to
+ * the guest memory system, since it allows the thread to block
+ * while memory is reclaimed, and won't take pages from emergency
+ * low-memory pools.
+ */
+#define VMW_PAGE_ALLOC_CANSLEEP		(GFP_HIGHUSER)
+
+/* Maximum number of page allocations without yielding processor */
+#define VMW_BALLOON_YIELD_THRESHOLD	1024
+
+/* Maximum number of refused pages we accumulate during inflation cycle */
+#define VMW_BALLOON_MAX_REFUSED		16
+
+/*
+ * Hypervisor communication port definitions.
+ */
+#define VMW_BALLOON_HV_PORT		0x5670
+#define VMW_BALLOON_HV_MAGIC		0x456c6d6f
+#define VMW_BALLOON_PROTOCOL_VERSION	2
+#define VMW_BALLOON_GUEST_ID		1	/* Linux */
+
+#define VMW_BALLOON_CMD_START		0
+#define VMW_BALLOON_CMD_GET_TARGET	1
+#define VMW_BALLOON_CMD_LOCK		2
+#define VMW_BALLOON_CMD_UNLOCK		3
+#define VMW_BALLOON_CMD_GUEST_ID	4
+
+/* error codes */
+#define VMW_BALLOON_SUCCESS		0
+#define VMW_BALLOON_FAILURE		-1
+#define VMW_BALLOON_ERROR_CMD_INVALID	1
+#define VMW_BALLOON_ERROR_PPN_INVALID	2
+#define VMW_BALLOON_ERROR_PPN_LOCKED	3
+#define VMW_BALLOON_ERROR_PPN_UNLOCKED	4
+#define VMW_BALLOON_ERROR_PPN_PINNED	5
+#define VMW_BALLOON_ERROR_PPN_NOTNEEDED	6
+#define VMW_BALLOON_ERROR_RESET		7
+#define VMW_BALLOON_ERROR_BUSY		8
+
+#define VMWARE_BALLOON_CMD(cmd, data, result)		\
+({							\
+	unsigned long __stat, __dummy1, __dummy2;	\
+	__asm__ __volatile__ ("inl (%%dx)" :		\
+		"=a"(__stat),				\
+		"=c"(__dummy1),				\
+		"=d"(__dummy2),				\
+		"=b"(result) :				\
+		"0"(VMW_BALLOON_HV_MAGIC),		\
+		"1"(VMW_BALLOON_CMD_##cmd),		\
+		"2"(VMW_BALLOON_HV_PORT),		\
+		"3"(data) :				\
+		"memory");				\
+	result &= -1UL;					\
+	__stat & -1UL;					\
+})
+
+#ifdef CONFIG_DEBUG_FS
+struct vmballoon_stats {
+	unsigned int timer;
+
+	/* allocation statustics */
+	unsigned int alloc;
+	unsigned int alloc_fail;
+	unsigned int sleep_alloc;
+	unsigned int sleep_alloc_fail;
+	unsigned int refused_alloc;
+	unsigned int refused_free;
+	unsigned int free;
+
+	/* monitor operations */
+	unsigned int lock;
+	unsigned int lock_fail;
+	unsigned int unlock;
+	unsigned int unlock_fail;
+	unsigned int target;
+	unsigned int target_fail;
+	unsigned int start;
+	unsigned int start_fail;
+	unsigned int guest_type;
+	unsigned int guest_type_fail;
+};
+
+#define STATS_INC(stat) (stat)++
+#else
+#define STATS_INC(stat)
+#endif
+
+struct vmballoon {
+
+	/* list of reserved physical pages */
+	struct list_head pages;
+
+	/* transient list of non-balloonable pages */
+	struct list_head refused_pages;
+	unsigned int n_refused_pages;
+
+	/* balloon size in pages */
+	unsigned int size;
+	unsigned int target;
+
+	/* reset flag */
+	bool reset_required;
+
+	/* adjustment rates (pages per second) */
+	unsigned int rate_alloc;
+	unsigned int rate_free;
+
+	/* slowdown page allocations for next few cycles */
+	unsigned int slow_allocation_cycles;
+
+#ifdef CONFIG_DEBUG_FS
+	/* statistics */
+	struct vmballoon_stats stats;
+
+	/* debugfs file exporting statistics */
+	struct dentry *dbg_entry;
+#endif
+
+	struct sysinfo sysinfo;
+
+	struct delayed_work dwork;
+};
+
+static struct vmballoon balloon;
+static struct workqueue_struct *vmballoon_wq;
+
+/*
+ * Send "start" command to the host, communicating supported version
+ * of the protocol.
+ */
+static bool vmballoon_send_start(struct vmballoon *b)
+{
+	unsigned long status, dummy;
+
+	STATS_INC(b->stats.start);
+
+	status = VMWARE_BALLOON_CMD(START, VMW_BALLOON_PROTOCOL_VERSION, dummy);
+	if (status == VMW_BALLOON_SUCCESS)
+		return true;
+
+	pr_debug("%s - failed, hv returns %ld\n", __func__, status);
+	STATS_INC(b->stats.start_fail);
+	return false;
+}
+
+static bool vmballoon_check_status(struct vmballoon *b, unsigned long status)
+{
+	switch (status) {
+	case VMW_BALLOON_SUCCESS:
+		return true;
+
+	case VMW_BALLOON_ERROR_RESET:
+		b->reset_required = true;
+		/* fall through */
+
+	default:
+		return false;
+	}
+}
+
+/*
+ * Communicate guest type to the host so that it can adjust ballooning
+ * algorithm to the one most appropriate for the guest. This command
+ * is normally issued after sending "start" command and is part of
+ * standard reset sequence.
+ */
+static bool vmballoon_send_guest_id(struct vmballoon *b)
+{
+	unsigned long status, dummy;
+
+	status = VMWARE_BALLOON_CMD(GUEST_ID, VMW_BALLOON_GUEST_ID, dummy);
+
+	STATS_INC(b->stats.guest_type);
+
+	if (vmballoon_check_status(b, status))
+		return true;
+
+	pr_debug("%s - failed, hv returns %ld\n", __func__, status);
+	STATS_INC(b->stats.guest_type_fail);
+	return false;
+}
+
+/*
+ * Retrieve desired balloon size from the host.
+ */
+static bool vmballoon_send_get_target(struct vmballoon *b, u32 *new_target)
+{
+	unsigned long status;
+	unsigned long target;
+	unsigned long limit;
+	u32 limit32;
+
+	/*
+	 * si_meminfo() is cheap. Moreover, we want to provide dynamic
+	 * max balloon size later. So let us call si_meminfo() every
+	 * iteration.
+	 */
+	si_meminfo(&b->sysinfo);
+	limit = b->sysinfo.totalram;
+
+	/* Ensure limit fits in 32-bits */
+	limit32 = (u32)limit;
+	if (limit != limit32)
+		return false;
+
+	/* update stats */
+	STATS_INC(b->stats.target);
+
+	status = VMWARE_BALLOON_CMD(GET_TARGET, limit, target);
+	if (vmballoon_check_status(b, status)) {
+		*new_target = target;
+		return true;
+	}
+
+	pr_debug("%s - failed, hv returns %ld\n", __func__, status);
+	STATS_INC(b->stats.target_fail);
+	return false;
+}
+
+/*
+ * Notify the host about allocated page so that host can use it without
+ * fear that guest will need it. Host may reject some pages, we need to
+ * check the return value and maybe submit a different page.
+ */
+static bool vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn)
+{
+	unsigned long status, dummy;
+	u32 pfn32;
+
+	pfn32 = (u32)pfn;
+	if (pfn32 != pfn)
+		return false;
+
+	STATS_INC(b->stats.lock);
+
+	status = VMWARE_BALLOON_CMD(LOCK, pfn, dummy);
+	if (vmballoon_check_status(b, status))
+		return true;
+
+	pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status);
+	STATS_INC(b->stats.lock_fail);
+	return false;
+}
+
+/*
+ * Notify the host that guest intends to release given page back into
+ * the pool of available (to the guest) pages.
+ */
+static bool vmballoon_send_unlock_page(struct vmballoon *b, unsigned long pfn)
+{
+	unsigned long status, dummy;
+	u32 pfn32;
+
+	pfn32 = (u32)pfn;
+	if (pfn32 != pfn)
+		return false;
+
+	STATS_INC(b->stats.unlock);
+
+	status = VMWARE_BALLOON_CMD(UNLOCK, pfn, dummy);
+	if (vmballoon_check_status(b, status))
+		return true;
+
+	pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status);
+	STATS_INC(b->stats.unlock_fail);
+	return false;
+}
+
+/*
+ * Quickly release all pages allocated for the balloon. This function is
+ * called when host decides to "reset" balloon for one reason or another.
+ * Unlike normal "deflate" we do not (shall not) notify host of the pages
+ * being released.
+ */
+static void vmballoon_pop(struct vmballoon *b)
+{
+	struct page *page, *next;
+	unsigned int count = 0;
+
+	list_for_each_entry_safe(page, next, &b->pages, lru) {
+		list_del(&page->lru);
+		__free_page(page);
+		STATS_INC(b->stats.free);
+		b->size--;
+
+		if (++count >= b->rate_free) {
+			count = 0;
+			cond_resched();
+		}
+	}
+}
+
+/*
+ * Perform standard reset sequence by popping the balloon (in case it
+ * is not  empty) and then restarting protocol. This operation normally
+ * happens when host responds with VMW_BALLOON_ERROR_RESET to a command.
+ */
+static void vmballoon_reset(struct vmballoon *b)
+{
+	/* free all pages, skipping monitor unlock */
+	vmballoon_pop(b);
+
+	if (vmballoon_send_start(b)) {
+		b->reset_required = false;
+		if (!vmballoon_send_guest_id(b))
+			pr_err("failed to send guest ID to the host\n");
+	}
+}
+
+/*
+ * Allocate (or reserve) a page for the balloon and notify the host.  If host
+ * refuses the page put it on "refuse" list and allocate another one until host
+ * is satisfied. "Refused" pages are released at the end of inflation cycle
+ * (when we allocate b->rate_alloc pages).
+ */
+static int vmballoon_reserve_page(struct vmballoon *b, bool can_sleep)
+{
+	struct page *page;
+	gfp_t flags;
+	bool locked = false;
+
+	do {
+		if (!can_sleep)
+			STATS_INC(b->stats.alloc);
+		else
+			STATS_INC(b->stats.sleep_alloc);
+
+		flags = can_sleep ? VMW_PAGE_ALLOC_CANSLEEP : VMW_PAGE_ALLOC_NOSLEEP;
+		page = alloc_page(flags);
+		if (!page) {
+			if (!can_sleep)
+				STATS_INC(b->stats.alloc_fail);
+			else
+				STATS_INC(b->stats.sleep_alloc_fail);
+			return -ENOMEM;
+		}
+
+		/* inform monitor */
+		locked = vmballoon_send_lock_page(b, page_to_pfn(page));
+		if (!locked) {
+			STATS_INC(b->stats.refused_alloc);
+
+			if (b->reset_required) {
+				__free_page(page);
+				return -EIO;
+			}
+
+			/*
+			 * Place page on the list of non-balloonable pages
+			 * and retry allocation, unless we already accumulated
+			 * too many of them, in which case take a breather.
+			 */
+			list_add(&page->lru, &b->refused_pages);
+			if (++b->n_refused_pages >= VMW_BALLOON_MAX_REFUSED)
+				return -EIO;
+		}
+	} while (!locked);
+
+	/* track allocated page */
+	list_add(&page->lru, &b->pages);
+
+	/* update balloon size */
+	b->size++;
+
+	return 0;
+}
+
+/*
+ * Release the page allocated for the balloon. Note that we first notify
+ * the host so it can make sure the page will be available for the guest
+ * to use, if needed.
+ */
+static int vmballoon_release_page(struct vmballoon *b, struct page *page)
+{
+	if (!vmballoon_send_unlock_page(b, page_to_pfn(page)))
+		return -EIO;
+
+	list_del(&page->lru);
+
+	/* deallocate page */
+	__free_page(page);
+	STATS_INC(b->stats.free);
+
+	/* update balloon size */
+	b->size--;
+
+	return 0;
+}
+
+/*
+ * Release pages that were allocated while attempting to inflate the
+ * balloon but were refused by the host for one reason or another.
+ */
+static void vmballoon_release_refused_pages(struct vmballoon *b)
+{
+	struct page *page, *next;
+
+	list_for_each_entry_safe(page, next, &b->refused_pages, lru) {
+		list_del(&page->lru);
+		__free_page(page);
+		STATS_INC(b->stats.refused_free);
+	}
+
+	b->n_refused_pages = 0;
+}
+
+/*
+ * Inflate the balloon towards its target size. Note that we try to limit
+ * the rate of allocation to make sure we are not choking the rest of the
+ * system.
+ */
+static void vmballoon_inflate(struct vmballoon *b)
+{
+	unsigned int goal;
+	unsigned int rate;
+	unsigned int i;
+	unsigned int allocations = 0;
+	int error = 0;
+	bool alloc_can_sleep = false;
+
+	pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target);
+
+	/*
+	 * First try NOSLEEP page allocations to inflate balloon.
+	 *
+	 * If we do not throttle nosleep allocations, we can drain all
+	 * free pages in the guest quickly (if the balloon target is high).
+	 * As a side-effect, draining free pages helps to inform (force)
+	 * the guest to start swapping if balloon target is not met yet,
+	 * which is a desired behavior. However, balloon driver can consume
+	 * all available CPU cycles if too many pages are allocated in a
+	 * second. Therefore, we throttle nosleep allocations even when
+	 * the guest is not under memory pressure. OTOH, if we have already
+	 * predicted that the guest is under memory pressure, then we
+	 * slowdown page allocations considerably.
+	 */
+
+	goal = b->target - b->size;
+	/*
+	 * Start with no sleep allocation rate which may be higher
+	 * than sleeping allocation rate.
+	 */
+	rate = b->slow_allocation_cycles ?
+			b->rate_alloc : VMW_BALLOON_NOSLEEP_ALLOC_MAX;
+
+	pr_debug("%s - goal: %d, no-sleep rate: %d, sleep rate: %d\n",
+		 __func__, goal, rate, b->rate_alloc);
+
+	for (i = 0; i < goal; i++) {
+
+		error = vmballoon_reserve_page(b, alloc_can_sleep);
+		if (error) {
+			if (error != -ENOMEM) {
+				/*
+				 * Not a page allocation failure, stop this
+				 * cycle. Maybe we'll get new target from
+				 * the host soon.
+				 */
+				break;
+			}
+
+			if (alloc_can_sleep) {
+				/*
+				 * CANSLEEP page allocation failed, so guest
+				 * is under severe memory pressure. Quickly
+				 * decrease allocation rate.
+				 */
+				b->rate_alloc = max(b->rate_alloc / 2,
+						    VMW_BALLOON_RATE_ALLOC_MIN);
+				break;
+			}
+
+			/*
+			 * NOSLEEP page allocation failed, so the guest is
+			 * under memory pressure. Let us slow down page
+			 * allocations for next few cycles so that the guest
+			 * gets out of memory pressure. Also, if we already
+			 * allocated b->rate_alloc pages, let's pause,
+			 * otherwise switch to sleeping allocations.
+			 */
+			b->slow_allocation_cycles = VMW_BALLOON_SLOW_CYCLES;
+
+			if (i >= b->rate_alloc)
+				break;
+
+			alloc_can_sleep = true;
+			/* Lower rate for sleeping allocations. */
+			rate = b->rate_alloc;
+		}
+
+		if (++allocations > VMW_BALLOON_YIELD_THRESHOLD) {
+			cond_resched();
+			allocations = 0;
+		}
+
+		if (i >= rate) {
+			/* We allocated enough pages, let's take a break. */
+			break;
+		}
+	}
+
+	/*
+	 * We reached our goal without failures so try increasing
+	 * allocation rate.
+	 */
+	if (error == 0 && i >= b->rate_alloc) {
+		unsigned int mult = i / b->rate_alloc;
+
+		b->rate_alloc =
+			min(b->rate_alloc + mult * VMW_BALLOON_RATE_ALLOC_INC,
+			    VMW_BALLOON_RATE_ALLOC_MAX);
+	}
+
+	vmballoon_release_refused_pages(b);
+}
+
+/*
+ * Decrease the size of the balloon allowing guest to use more memory.
+ */
+static void vmballoon_deflate(struct vmballoon *b)
+{
+	struct page *page, *next;
+	unsigned int i = 0;
+	unsigned int goal;
+	int error;
+
+	pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target);
+
+	/* limit deallocation rate */
+	goal = min(b->size - b->target, b->rate_free);
+
+	pr_debug("%s - goal: %d, rate: %d\n", __func__, goal, b->rate_free);
+
+	/* free pages to reach target */
+	list_for_each_entry_safe(page, next, &b->pages, lru) {
+		error = vmballoon_release_page(b, page);
+		if (error) {
+			/* quickly decrease rate in case of error */
+			b->rate_free = max(b->rate_free / 2,
+					   VMW_BALLOON_RATE_FREE_MIN);
+			return;
+		}
+
+		if (++i >= goal)
+			break;
+	}
+
+	/* slowly increase rate if there were no errors */
+	b->rate_free = min(b->rate_free + VMW_BALLOON_RATE_FREE_INC,
+			   VMW_BALLOON_RATE_FREE_MAX);
+}
+
+/*
+ * Balloon work function: reset protocol, if needed, get the new size and
+ * adjust balloon as needed. Repeat in 1 sec.
+ */
+static void vmballoon_work(struct work_struct *work)
+{
+	struct delayed_work *dwork = to_delayed_work(work);
+	struct vmballoon *b = container_of(dwork, struct vmballoon, dwork);
+	unsigned int target;
+
+	STATS_INC(b->stats.timer);
+
+	if (b->reset_required)
+		vmballoon_reset(b);
+
+	if (b->slow_allocation_cycles > 0)
+		b->slow_allocation_cycles--;
+
+	if (vmballoon_send_get_target(b, &target)) {
+		/* update target, adjust size */
+		b->target = target;
+
+		if (b->size < target)
+			vmballoon_inflate(b);
+		else if (b->size > target)
+			vmballoon_deflate(b);
+	}
+
+	queue_delayed_work(vmballoon_wq, dwork, round_jiffies_relative(HZ));
+}
+
+/*
+ * DEBUGFS Interface
+ */
+#ifdef CONFIG_DEBUG_FS
+
+static int vmballoon_debug_show(struct seq_file *f, void *offset)
+{
+	struct vmballoon *b = f->private;
+	struct vmballoon_stats *stats = &b->stats;
+
+	/* format size info */
+	seq_printf(f,
+		   "target:             %8d pages\n"
+		   "current:            %8d pages\n",
+		   b->target, b->size);
+
+	/* format rate info */
+	seq_printf(f,
+		   "rateNoSleepAlloc:   %8d pages/sec\n"
+		   "rateSleepAlloc:     %8d pages/sec\n"
+		   "rateFree:           %8d pages/sec\n",
+		   VMW_BALLOON_NOSLEEP_ALLOC_MAX,
+		   b->rate_alloc, b->rate_free);
+
+	seq_printf(f,
+		   "\n"
+		   "timer:              %8u\n"
+		   "start:              %8u (%4u failed)\n"
+		   "guestType:          %8u (%4u failed)\n"
+		   "lock:               %8u (%4u failed)\n"
+		   "unlock:             %8u (%4u failed)\n"
+		   "target:             %8u (%4u failed)\n"
+		   "primNoSleepAlloc:   %8u (%4u failed)\n"
+		   "primCanSleepAlloc:  %8u (%4u failed)\n"
+		   "primFree:           %8u\n"
+		   "errAlloc:           %8u\n"
+		   "errFree:            %8u\n",
+		   stats->timer,
+		   stats->start, stats->start_fail,
+		   stats->guest_type, stats->guest_type_fail,
+		   stats->lock,  stats->lock_fail,
+		   stats->unlock, stats->unlock_fail,
+		   stats->target, stats->target_fail,
+		   stats->alloc, stats->alloc_fail,
+		   stats->sleep_alloc, stats->sleep_alloc_fail,
+		   stats->free,
+		   stats->refused_alloc, stats->refused_free);
+
+	return 0;
+}
+
+static int vmballoon_debug_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, vmballoon_debug_show, inode->i_private);
+}
+
+static const struct file_operations vmballoon_debug_fops = {
+	.owner		= THIS_MODULE,
+	.open		= vmballoon_debug_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init vmballoon_debugfs_init(struct vmballoon *b)
+{
+	int error;
+
+	b->dbg_entry = debugfs_create_file("vmmemctl", S_IRUGO, NULL, b,
+					   &vmballoon_debug_fops);
+	if (IS_ERR(b->dbg_entry)) {
+		error = PTR_ERR(b->dbg_entry);
+		pr_err("failed to create debugfs entry, error: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static void __exit vmballoon_debugfs_exit(struct vmballoon *b)
+{
+	debugfs_remove(b->dbg_entry);
+}
+
+#else
+
+static inline int vmballoon_debugfs_init(struct vmballoon *b)
+{
+	return 0;
+}
+
+static inline void vmballoon_debugfs_exit(struct vmballoon *b)
+{
+}
+
+#endif	/* CONFIG_DEBUG_FS */
+
+static int __init vmballoon_init(void)
+{
+	int error;
+
+	/*
+	 * Check if we are running on VMware's hypervisor and bail out
+	 * if we are not.
+	 */
+	if (x86_hyper != &x86_hyper_vmware)
+		return -ENODEV;
+
+	vmballoon_wq = create_freezeable_workqueue("vmmemctl");
+	if (!vmballoon_wq) {
+		pr_err("failed to create workqueue\n");
+		return -ENOMEM;
+	}
+
+	INIT_LIST_HEAD(&balloon.pages);
+	INIT_LIST_HEAD(&balloon.refused_pages);
+
+	/* initialize rates */
+	balloon.rate_alloc = VMW_BALLOON_RATE_ALLOC_MAX;
+	balloon.rate_free = VMW_BALLOON_RATE_FREE_MAX;
+
+	INIT_DELAYED_WORK(&balloon.dwork, vmballoon_work);
+
+	/*
+	 * Start balloon.
+	 */
+	if (!vmballoon_send_start(&balloon)) {
+		pr_err("failed to send start command to the host\n");
+		error = -EIO;
+		goto fail;
+	}
+
+	if (!vmballoon_send_guest_id(&balloon)) {
+		pr_err("failed to send guest ID to the host\n");
+		error = -EIO;
+		goto fail;
+	}
+
+	error = vmballoon_debugfs_init(&balloon);
+	if (error)
+		goto fail;
+
+	queue_delayed_work(vmballoon_wq, &balloon.dwork, 0);
+
+	return 0;
+
+fail:
+	destroy_workqueue(vmballoon_wq);
+	return error;
+}
+module_init(vmballoon_init);
+
+static void __exit vmballoon_exit(void)
+{
+	cancel_delayed_work_sync(&balloon.dwork);
+	destroy_workqueue(vmballoon_wq);
+
+	vmballoon_debugfs_exit(&balloon);
+
+	/*
+	 * Deallocate all reserved memory, and reset connection with monitor.
+	 * Reset connection before deallocating memory to avoid potential for
+	 * additional spurious resets from guest touching deallocated pages.
+	 */
+	vmballoon_send_start(&balloon);
+	vmballoon_pop(&balloon);
+}
+module_exit(vmballoon_exit);
diff --git a/drivers/misc/vmware_balloon.c b/drivers/misc/vmware_balloon.c
deleted file mode 100644
index 2a1e804..0000000
--- a/drivers/misc/vmware_balloon.c
+++ /dev/null
@@ -1,844 +0,0 @@
-/*
- * VMware Balloon driver.
- *
- * Copyright (C) 2000-2010, VMware, Inc. All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; version 2 of the License and no later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- * NON INFRINGEMENT.  See the GNU General Public License for more
- * details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Maintained by: Dmitry Torokhov <dtor@vmware.com>
- */
-
-/*
- * This is VMware physical memory management driver for Linux. The driver
- * acts like a "balloon" that can be inflated to reclaim physical pages by
- * reserving them in the guest and invalidating them in the monitor,
- * freeing up the underlying machine pages so they can be allocated to
- * other guests.  The balloon can also be deflated to allow the guest to
- * use more physical memory. Higher level policies can control the sizes
- * of balloons in VMs in order to manage physical memory resources.
- */
-
-//#define DEBUG
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/types.h>
-#include <linux/kernel.h>
-#include <linux/mm.h>
-#include <linux/sched.h>
-#include <linux/module.h>
-#include <linux/workqueue.h>
-#include <linux/debugfs.h>
-#include <linux/seq_file.h>
-#include <asm/hypervisor.h>
-
-MODULE_AUTHOR("VMware, Inc.");
-MODULE_DESCRIPTION("VMware Memory Control (Balloon) Driver");
-MODULE_VERSION("1.2.1.1-k");
-MODULE_ALIAS("dmi:*:svnVMware*:*");
-MODULE_ALIAS("vmware_vmmemctl");
-MODULE_LICENSE("GPL");
-
-/*
- * Various constants controlling rate of inflaint/deflating balloon,
- * measured in pages.
- */
-
-/*
- * Rate of allocating memory when there is no memory pressure
- * (driver performs non-sleeping allocations).
- */
-#define VMW_BALLOON_NOSLEEP_ALLOC_MAX	16384U
-
-/*
- * Rates of memory allocaton when guest experiences memory pressure
- * (driver performs sleeping allocations).
- */
-#define VMW_BALLOON_RATE_ALLOC_MIN	512U
-#define VMW_BALLOON_RATE_ALLOC_MAX	2048U
-#define VMW_BALLOON_RATE_ALLOC_INC	16U
-
-/*
- * Rates for releasing pages while deflating balloon.
- */
-#define VMW_BALLOON_RATE_FREE_MIN	512U
-#define VMW_BALLOON_RATE_FREE_MAX	16384U
-#define VMW_BALLOON_RATE_FREE_INC	16U
-
-/*
- * When guest is under memory pressure, use a reduced page allocation
- * rate for next several cycles.
- */
-#define VMW_BALLOON_SLOW_CYCLES		4
-
-/*
- * Use __GFP_HIGHMEM to allow pages from HIGHMEM zone. We don't
- * allow wait (__GFP_WAIT) for NOSLEEP page allocations. Use
- * __GFP_NOWARN, to suppress page allocation failure warnings.
- */
-#define VMW_PAGE_ALLOC_NOSLEEP		(__GFP_HIGHMEM|__GFP_NOWARN)
-
-/*
- * Use GFP_HIGHUSER when executing in a separate kernel thread
- * context and allocation can sleep.  This is less stressful to
- * the guest memory system, since it allows the thread to block
- * while memory is reclaimed, and won't take pages from emergency
- * low-memory pools.
- */
-#define VMW_PAGE_ALLOC_CANSLEEP		(GFP_HIGHUSER)
-
-/* Maximum number of page allocations without yielding processor */
-#define VMW_BALLOON_YIELD_THRESHOLD	1024
-
-/* Maximum number of refused pages we accumulate during inflation cycle */
-#define VMW_BALLOON_MAX_REFUSED		16
-
-/*
- * Hypervisor communication port definitions.
- */
-#define VMW_BALLOON_HV_PORT		0x5670
-#define VMW_BALLOON_HV_MAGIC		0x456c6d6f
-#define VMW_BALLOON_PROTOCOL_VERSION	2
-#define VMW_BALLOON_GUEST_ID		1	/* Linux */
-
-#define VMW_BALLOON_CMD_START		0
-#define VMW_BALLOON_CMD_GET_TARGET	1
-#define VMW_BALLOON_CMD_LOCK		2
-#define VMW_BALLOON_CMD_UNLOCK		3
-#define VMW_BALLOON_CMD_GUEST_ID	4
-
-/* error codes */
-#define VMW_BALLOON_SUCCESS		0
-#define VMW_BALLOON_FAILURE		-1
-#define VMW_BALLOON_ERROR_CMD_INVALID	1
-#define VMW_BALLOON_ERROR_PPN_INVALID	2
-#define VMW_BALLOON_ERROR_PPN_LOCKED	3
-#define VMW_BALLOON_ERROR_PPN_UNLOCKED	4
-#define VMW_BALLOON_ERROR_PPN_PINNED	5
-#define VMW_BALLOON_ERROR_PPN_NOTNEEDED	6
-#define VMW_BALLOON_ERROR_RESET		7
-#define VMW_BALLOON_ERROR_BUSY		8
-
-#define VMWARE_BALLOON_CMD(cmd, data, result)		\
-({							\
-	unsigned long __stat, __dummy1, __dummy2;	\
-	__asm__ __volatile__ ("inl (%%dx)" :		\
-		"=a"(__stat),				\
-		"=c"(__dummy1),				\
-		"=d"(__dummy2),				\
-		"=b"(result) :				\
-		"0"(VMW_BALLOON_HV_MAGIC),		\
-		"1"(VMW_BALLOON_CMD_##cmd),		\
-		"2"(VMW_BALLOON_HV_PORT),		\
-		"3"(data) :				\
-		"memory");				\
-	result &= -1UL;					\
-	__stat & -1UL;					\
-})
-
-#ifdef CONFIG_DEBUG_FS
-struct vmballoon_stats {
-	unsigned int timer;
-
-	/* allocation statustics */
-	unsigned int alloc;
-	unsigned int alloc_fail;
-	unsigned int sleep_alloc;
-	unsigned int sleep_alloc_fail;
-	unsigned int refused_alloc;
-	unsigned int refused_free;
-	unsigned int free;
-
-	/* monitor operations */
-	unsigned int lock;
-	unsigned int lock_fail;
-	unsigned int unlock;
-	unsigned int unlock_fail;
-	unsigned int target;
-	unsigned int target_fail;
-	unsigned int start;
-	unsigned int start_fail;
-	unsigned int guest_type;
-	unsigned int guest_type_fail;
-};
-
-#define STATS_INC(stat) (stat)++
-#else
-#define STATS_INC(stat)
-#endif
-
-struct vmballoon {
-
-	/* list of reserved physical pages */
-	struct list_head pages;
-
-	/* transient list of non-balloonable pages */
-	struct list_head refused_pages;
-	unsigned int n_refused_pages;
-
-	/* balloon size in pages */
-	unsigned int size;
-	unsigned int target;
-
-	/* reset flag */
-	bool reset_required;
-
-	/* adjustment rates (pages per second) */
-	unsigned int rate_alloc;
-	unsigned int rate_free;
-
-	/* slowdown page allocations for next few cycles */
-	unsigned int slow_allocation_cycles;
-
-#ifdef CONFIG_DEBUG_FS
-	/* statistics */
-	struct vmballoon_stats stats;
-
-	/* debugfs file exporting statistics */
-	struct dentry *dbg_entry;
-#endif
-
-	struct sysinfo sysinfo;
-
-	struct delayed_work dwork;
-};
-
-static struct vmballoon balloon;
-static struct workqueue_struct *vmballoon_wq;
-
-/*
- * Send "start" command to the host, communicating supported version
- * of the protocol.
- */
-static bool vmballoon_send_start(struct vmballoon *b)
-{
-	unsigned long status, dummy;
-
-	STATS_INC(b->stats.start);
-
-	status = VMWARE_BALLOON_CMD(START, VMW_BALLOON_PROTOCOL_VERSION, dummy);
-	if (status == VMW_BALLOON_SUCCESS)
-		return true;
-
-	pr_debug("%s - failed, hv returns %ld\n", __func__, status);
-	STATS_INC(b->stats.start_fail);
-	return false;
-}
-
-static bool vmballoon_check_status(struct vmballoon *b, unsigned long status)
-{
-	switch (status) {
-	case VMW_BALLOON_SUCCESS:
-		return true;
-
-	case VMW_BALLOON_ERROR_RESET:
-		b->reset_required = true;
-		/* fall through */
-
-	default:
-		return false;
-	}
-}
-
-/*
- * Communicate guest type to the host so that it can adjust ballooning
- * algorithm to the one most appropriate for the guest. This command
- * is normally issued after sending "start" command and is part of
- * standard reset sequence.
- */
-static bool vmballoon_send_guest_id(struct vmballoon *b)
-{
-	unsigned long status, dummy;
-
-	status = VMWARE_BALLOON_CMD(GUEST_ID, VMW_BALLOON_GUEST_ID, dummy);
-
-	STATS_INC(b->stats.guest_type);
-
-	if (vmballoon_check_status(b, status))
-		return true;
-
-	pr_debug("%s - failed, hv returns %ld\n", __func__, status);
-	STATS_INC(b->stats.guest_type_fail);
-	return false;
-}
-
-/*
- * Retrieve desired balloon size from the host.
- */
-static bool vmballoon_send_get_target(struct vmballoon *b, u32 *new_target)
-{
-	unsigned long status;
-	unsigned long target;
-	unsigned long limit;
-	u32 limit32;
-
-	/*
-	 * si_meminfo() is cheap. Moreover, we want to provide dynamic
-	 * max balloon size later. So let us call si_meminfo() every
-	 * iteration.
-	 */
-	si_meminfo(&b->sysinfo);
-	limit = b->sysinfo.totalram;
-
-	/* Ensure limit fits in 32-bits */
-	limit32 = (u32)limit;
-	if (limit != limit32)
-		return false;
-
-	/* update stats */
-	STATS_INC(b->stats.target);
-
-	status = VMWARE_BALLOON_CMD(GET_TARGET, limit, target);
-	if (vmballoon_check_status(b, status)) {
-		*new_target = target;
-		return true;
-	}
-
-	pr_debug("%s - failed, hv returns %ld\n", __func__, status);
-	STATS_INC(b->stats.target_fail);
-	return false;
-}
-
-/*
- * Notify the host about allocated page so that host can use it without
- * fear that guest will need it. Host may reject some pages, we need to
- * check the return value and maybe submit a different page.
- */
-static bool vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn)
-{
-	unsigned long status, dummy;
-	u32 pfn32;
-
-	pfn32 = (u32)pfn;
-	if (pfn32 != pfn)
-		return false;
-
-	STATS_INC(b->stats.lock);
-
-	status = VMWARE_BALLOON_CMD(LOCK, pfn, dummy);
-	if (vmballoon_check_status(b, status))
-		return true;
-
-	pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status);
-	STATS_INC(b->stats.lock_fail);
-	return false;
-}
-
-/*
- * Notify the host that guest intends to release given page back into
- * the pool of available (to the guest) pages.
- */
-static bool vmballoon_send_unlock_page(struct vmballoon *b, unsigned long pfn)
-{
-	unsigned long status, dummy;
-	u32 pfn32;
-
-	pfn32 = (u32)pfn;
-	if (pfn32 != pfn)
-		return false;
-
-	STATS_INC(b->stats.unlock);
-
-	status = VMWARE_BALLOON_CMD(UNLOCK, pfn, dummy);
-	if (vmballoon_check_status(b, status))
-		return true;
-
-	pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status);
-	STATS_INC(b->stats.unlock_fail);
-	return false;
-}
-
-/*
- * Quickly release all pages allocated for the balloon. This function is
- * called when host decides to "reset" balloon for one reason or another.
- * Unlike normal "deflate" we do not (shall not) notify host of the pages
- * being released.
- */
-static void vmballoon_pop(struct vmballoon *b)
-{
-	struct page *page, *next;
-	unsigned int count = 0;
-
-	list_for_each_entry_safe(page, next, &b->pages, lru) {
-		list_del(&page->lru);
-		__free_page(page);
-		STATS_INC(b->stats.free);
-		b->size--;
-
-		if (++count >= b->rate_free) {
-			count = 0;
-			cond_resched();
-		}
-	}
-}
-
-/*
- * Perform standard reset sequence by popping the balloon (in case it
- * is not  empty) and then restarting protocol. This operation normally
- * happens when host responds with VMW_BALLOON_ERROR_RESET to a command.
- */
-static void vmballoon_reset(struct vmballoon *b)
-{
-	/* free all pages, skipping monitor unlock */
-	vmballoon_pop(b);
-
-	if (vmballoon_send_start(b)) {
-		b->reset_required = false;
-		if (!vmballoon_send_guest_id(b))
-			pr_err("failed to send guest ID to the host\n");
-	}
-}
-
-/*
- * Allocate (or reserve) a page for the balloon and notify the host.  If host
- * refuses the page put it on "refuse" list and allocate another one until host
- * is satisfied. "Refused" pages are released at the end of inflation cycle
- * (when we allocate b->rate_alloc pages).
- */
-static int vmballoon_reserve_page(struct vmballoon *b, bool can_sleep)
-{
-	struct page *page;
-	gfp_t flags;
-	bool locked = false;
-
-	do {
-		if (!can_sleep)
-			STATS_INC(b->stats.alloc);
-		else
-			STATS_INC(b->stats.sleep_alloc);
-
-		flags = can_sleep ? VMW_PAGE_ALLOC_CANSLEEP : VMW_PAGE_ALLOC_NOSLEEP;
-		page = alloc_page(flags);
-		if (!page) {
-			if (!can_sleep)
-				STATS_INC(b->stats.alloc_fail);
-			else
-				STATS_INC(b->stats.sleep_alloc_fail);
-			return -ENOMEM;
-		}
-
-		/* inform monitor */
-		locked = vmballoon_send_lock_page(b, page_to_pfn(page));
-		if (!locked) {
-			STATS_INC(b->stats.refused_alloc);
-
-			if (b->reset_required) {
-				__free_page(page);
-				return -EIO;
-			}
-
-			/*
-			 * Place page on the list of non-balloonable pages
-			 * and retry allocation, unless we already accumulated
-			 * too many of them, in which case take a breather.
-			 */
-			list_add(&page->lru, &b->refused_pages);
-			if (++b->n_refused_pages >= VMW_BALLOON_MAX_REFUSED)
-				return -EIO;
-		}
-	} while (!locked);
-
-	/* track allocated page */
-	list_add(&page->lru, &b->pages);
-
-	/* update balloon size */
-	b->size++;
-
-	return 0;
-}
-
-/*
- * Release the page allocated for the balloon. Note that we first notify
- * the host so it can make sure the page will be available for the guest
- * to use, if needed.
- */
-static int vmballoon_release_page(struct vmballoon *b, struct page *page)
-{
-	if (!vmballoon_send_unlock_page(b, page_to_pfn(page)))
-		return -EIO;
-
-	list_del(&page->lru);
-
-	/* deallocate page */
-	__free_page(page);
-	STATS_INC(b->stats.free);
-
-	/* update balloon size */
-	b->size--;
-
-	return 0;
-}
-
-/*
- * Release pages that were allocated while attempting to inflate the
- * balloon but were refused by the host for one reason or another.
- */
-static void vmballoon_release_refused_pages(struct vmballoon *b)
-{
-	struct page *page, *next;
-
-	list_for_each_entry_safe(page, next, &b->refused_pages, lru) {
-		list_del(&page->lru);
-		__free_page(page);
-		STATS_INC(b->stats.refused_free);
-	}
-
-	b->n_refused_pages = 0;
-}
-
-/*
- * Inflate the balloon towards its target size. Note that we try to limit
- * the rate of allocation to make sure we are not choking the rest of the
- * system.
- */
-static void vmballoon_inflate(struct vmballoon *b)
-{
-	unsigned int goal;
-	unsigned int rate;
-	unsigned int i;
-	unsigned int allocations = 0;
-	int error = 0;
-	bool alloc_can_sleep = false;
-
-	pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target);
-
-	/*
-	 * First try NOSLEEP page allocations to inflate balloon.
-	 *
-	 * If we do not throttle nosleep allocations, we can drain all
-	 * free pages in the guest quickly (if the balloon target is high).
-	 * As a side-effect, draining free pages helps to inform (force)
-	 * the guest to start swapping if balloon target is not met yet,
-	 * which is a desired behavior. However, balloon driver can consume
-	 * all available CPU cycles if too many pages are allocated in a
-	 * second. Therefore, we throttle nosleep allocations even when
-	 * the guest is not under memory pressure. OTOH, if we have already
-	 * predicted that the guest is under memory pressure, then we
-	 * slowdown page allocations considerably.
-	 */
-
-	goal = b->target - b->size;
-	/*
-	 * Start with no sleep allocation rate which may be higher
-	 * than sleeping allocation rate.
-	 */
-	rate = b->slow_allocation_cycles ?
-			b->rate_alloc : VMW_BALLOON_NOSLEEP_ALLOC_MAX;
-
-	pr_debug("%s - goal: %d, no-sleep rate: %d, sleep rate: %d\n",
-		 __func__, goal, rate, b->rate_alloc);
-
-	for (i = 0; i < goal; i++) {
-
-		error = vmballoon_reserve_page(b, alloc_can_sleep);
-		if (error) {
-			if (error != -ENOMEM) {
-				/*
-				 * Not a page allocation failure, stop this
-				 * cycle. Maybe we'll get new target from
-				 * the host soon.
-				 */
-				break;
-			}
-
-			if (alloc_can_sleep) {
-				/*
-				 * CANSLEEP page allocation failed, so guest
-				 * is under severe memory pressure. Quickly
-				 * decrease allocation rate.
-				 */
-				b->rate_alloc = max(b->rate_alloc / 2,
-						    VMW_BALLOON_RATE_ALLOC_MIN);
-				break;
-			}
-
-			/*
-			 * NOSLEEP page allocation failed, so the guest is
-			 * under memory pressure. Let us slow down page
-			 * allocations for next few cycles so that the guest
-			 * gets out of memory pressure. Also, if we already
-			 * allocated b->rate_alloc pages, let's pause,
-			 * otherwise switch to sleeping allocations.
-			 */
-			b->slow_allocation_cycles = VMW_BALLOON_SLOW_CYCLES;
-
-			if (i >= b->rate_alloc)
-				break;
-
-			alloc_can_sleep = true;
-			/* Lower rate for sleeping allocations. */
-			rate = b->rate_alloc;
-		}
-
-		if (++allocations > VMW_BALLOON_YIELD_THRESHOLD) {
-			cond_resched();
-			allocations = 0;
-		}
-
-		if (i >= rate) {
-			/* We allocated enough pages, let's take a break. */
-			break;
-		}
-	}
-
-	/*
-	 * We reached our goal without failures so try increasing
-	 * allocation rate.
-	 */
-	if (error == 0 && i >= b->rate_alloc) {
-		unsigned int mult = i / b->rate_alloc;
-
-		b->rate_alloc =
-			min(b->rate_alloc + mult * VMW_BALLOON_RATE_ALLOC_INC,
-			    VMW_BALLOON_RATE_ALLOC_MAX);
-	}
-
-	vmballoon_release_refused_pages(b);
-}
-
-/*
- * Decrease the size of the balloon allowing guest to use more memory.
- */
-static void vmballoon_deflate(struct vmballoon *b)
-{
-	struct page *page, *next;
-	unsigned int i = 0;
-	unsigned int goal;
-	int error;
-
-	pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target);
-
-	/* limit deallocation rate */
-	goal = min(b->size - b->target, b->rate_free);
-
-	pr_debug("%s - goal: %d, rate: %d\n", __func__, goal, b->rate_free);
-
-	/* free pages to reach target */
-	list_for_each_entry_safe(page, next, &b->pages, lru) {
-		error = vmballoon_release_page(b, page);
-		if (error) {
-			/* quickly decrease rate in case of error */
-			b->rate_free = max(b->rate_free / 2,
-					   VMW_BALLOON_RATE_FREE_MIN);
-			return;
-		}
-
-		if (++i >= goal)
-			break;
-	}
-
-	/* slowly increase rate if there were no errors */
-	b->rate_free = min(b->rate_free + VMW_BALLOON_RATE_FREE_INC,
-			   VMW_BALLOON_RATE_FREE_MAX);
-}
-
-/*
- * Balloon work function: reset protocol, if needed, get the new size and
- * adjust balloon as needed. Repeat in 1 sec.
- */
-static void vmballoon_work(struct work_struct *work)
-{
-	struct delayed_work *dwork = to_delayed_work(work);
-	struct vmballoon *b = container_of(dwork, struct vmballoon, dwork);
-	unsigned int target;
-
-	STATS_INC(b->stats.timer);
-
-	if (b->reset_required)
-		vmballoon_reset(b);
-
-	if (b->slow_allocation_cycles > 0)
-		b->slow_allocation_cycles--;
-
-	if (vmballoon_send_get_target(b, &target)) {
-		/* update target, adjust size */
-		b->target = target;
-
-		if (b->size < target)
-			vmballoon_inflate(b);
-		else if (b->size > target)
-			vmballoon_deflate(b);
-	}
-
-	queue_delayed_work(vmballoon_wq, dwork, round_jiffies_relative(HZ));
-}
-
-/*
- * DEBUGFS Interface
- */
-#ifdef CONFIG_DEBUG_FS
-
-static int vmballoon_debug_show(struct seq_file *f, void *offset)
-{
-	struct vmballoon *b = f->private;
-	struct vmballoon_stats *stats = &b->stats;
-
-	/* format size info */
-	seq_printf(f,
-		   "target:             %8d pages\n"
-		   "current:            %8d pages\n",
-		   b->target, b->size);
-
-	/* format rate info */
-	seq_printf(f,
-		   "rateNoSleepAlloc:   %8d pages/sec\n"
-		   "rateSleepAlloc:     %8d pages/sec\n"
-		   "rateFree:           %8d pages/sec\n",
-		   VMW_BALLOON_NOSLEEP_ALLOC_MAX,
-		   b->rate_alloc, b->rate_free);
-
-	seq_printf(f,
-		   "\n"
-		   "timer:              %8u\n"
-		   "start:              %8u (%4u failed)\n"
-		   "guestType:          %8u (%4u failed)\n"
-		   "lock:               %8u (%4u failed)\n"
-		   "unlock:             %8u (%4u failed)\n"
-		   "target:             %8u (%4u failed)\n"
-		   "primNoSleepAlloc:   %8u (%4u failed)\n"
-		   "primCanSleepAlloc:  %8u (%4u failed)\n"
-		   "primFree:           %8u\n"
-		   "errAlloc:           %8u\n"
-		   "errFree:            %8u\n",
-		   stats->timer,
-		   stats->start, stats->start_fail,
-		   stats->guest_type, stats->guest_type_fail,
-		   stats->lock,  stats->lock_fail,
-		   stats->unlock, stats->unlock_fail,
-		   stats->target, stats->target_fail,
-		   stats->alloc, stats->alloc_fail,
-		   stats->sleep_alloc, stats->sleep_alloc_fail,
-		   stats->free,
-		   stats->refused_alloc, stats->refused_free);
-
-	return 0;
-}
-
-static int vmballoon_debug_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, vmballoon_debug_show, inode->i_private);
-}
-
-static const struct file_operations vmballoon_debug_fops = {
-	.owner		= THIS_MODULE,
-	.open		= vmballoon_debug_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
-
-static int __init vmballoon_debugfs_init(struct vmballoon *b)
-{
-	int error;
-
-	b->dbg_entry = debugfs_create_file("vmmemctl", S_IRUGO, NULL, b,
-					   &vmballoon_debug_fops);
-	if (IS_ERR(b->dbg_entry)) {
-		error = PTR_ERR(b->dbg_entry);
-		pr_err("failed to create debugfs entry, error: %d\n", error);
-		return error;
-	}
-
-	return 0;
-}
-
-static void __exit vmballoon_debugfs_exit(struct vmballoon *b)
-{
-	debugfs_remove(b->dbg_entry);
-}
-
-#else
-
-static inline int vmballoon_debugfs_init(struct vmballoon *b)
-{
-	return 0;
-}
-
-static inline void vmballoon_debugfs_exit(struct vmballoon *b)
-{
-}
-
-#endif	/* CONFIG_DEBUG_FS */
-
-static int __init vmballoon_init(void)
-{
-	int error;
-
-	/*
-	 * Check if we are running on VMware's hypervisor and bail out
-	 * if we are not.
-	 */
-	if (x86_hyper != &x86_hyper_vmware)
-		return -ENODEV;
-
-	vmballoon_wq = create_freezeable_workqueue("vmmemctl");
-	if (!vmballoon_wq) {
-		pr_err("failed to create workqueue\n");
-		return -ENOMEM;
-	}
-
-	INIT_LIST_HEAD(&balloon.pages);
-	INIT_LIST_HEAD(&balloon.refused_pages);
-
-	/* initialize rates */
-	balloon.rate_alloc = VMW_BALLOON_RATE_ALLOC_MAX;
-	balloon.rate_free = VMW_BALLOON_RATE_FREE_MAX;
-
-	INIT_DELAYED_WORK(&balloon.dwork, vmballoon_work);
-
-	/*
-	 * Start balloon.
-	 */
-	if (!vmballoon_send_start(&balloon)) {
-		pr_err("failed to send start command to the host\n");
-		error = -EIO;
-		goto fail;
-	}
-
-	if (!vmballoon_send_guest_id(&balloon)) {
-		pr_err("failed to send guest ID to the host\n");
-		error = -EIO;
-		goto fail;
-	}
-
-	error = vmballoon_debugfs_init(&balloon);
-	if (error)
-		goto fail;
-
-	queue_delayed_work(vmballoon_wq, &balloon.dwork, 0);
-
-	return 0;
-
-fail:
-	destroy_workqueue(vmballoon_wq);
-	return error;
-}
-module_init(vmballoon_init);
-
-static void __exit vmballoon_exit(void)
-{
-	cancel_delayed_work_sync(&balloon.dwork);
-	destroy_workqueue(vmballoon_wq);
-
-	vmballoon_debugfs_exit(&balloon);
-
-	/*
-	 * Deallocate all reserved memory, and reset connection with monitor.
-	 * Reset connection before deallocating memory to avoid potential for
-	 * additional spurious resets from guest touching deallocated pages.
-	 */
-	vmballoon_send_start(&balloon);
-	vmballoon_pop(&balloon);
-}
-module_exit(vmballoon_exit);
-- 
1.7.0