[PATCH v5 2/7] VMware balloon: Update balloon target on each lock/unlock.

Philip P. Moltmann
2015-08-06T22:21:16Z

From: Xavier Deguillard <xdeguillard@vmware.com>

Instead of waiting for the next GET_TARGET command, we can react faster
by exploiting the fact that each hypervisor call also returns the
balloon target.

Signed-off-by: Xavier Deguillard <xdeguillard@vmware.com>
Acked-by: Dmitry Torokhov <dtor@vmware.com>
Signed-off-by: Philip P. Moltmann <moltmann@vmware.com>
Acked-by: Andy King <acking@vmware.com>
---
drivers/misc/vmw_balloon.c | 85 +++++++++++++++++++++++-----------------------
1 file changed, 42 insertions(+), 43 deletions(-)

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 64f275e..0b5aa93 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -47,7 +47,7 @@

MODULE_AUTHOR("VMware, Inc.");
MODULE_DESCRIPTION("VMware Memory Control (Balloon) Driver");
-MODULE_VERSION("1.3.1.0-k");
+MODULE_VERSION("1.3.2.0-k");
MODULE_ALIAS("dmi:*:svnVMware*:*");
MODULE_ALIAS("vmware_vmmemctl");
MODULE_LICENSE("GPL");
@@ -255,8 +255,10 @@ struct vmballoon;

struct vmballoon_ops {
void (*add_page)(struct vmballoon *b, int idx, struct page *p);
- int (*lock)(struct vmballoon *b, unsigned int num_pages);
- int (*unlock)(struct vmballoon *b, unsigned int num_pages);
+ int (*lock)(struct vmballoon *b, unsigned int num_pages,
+ unsigned int *target);
+ int (*unlock)(struct vmballoon *b, unsigned int num_pages,
+ unsigned int *target);
};

struct vmballoon {
@@ -413,7 +415,7 @@ static bool vmballoon_send_get_target(struct vmballoon *b, u32 *new_target)
* check the return value and maybe submit a different page.
*/
static int vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn,
- unsigned int *hv_status)
+ unsigned int *hv_status, unsigned int *target)
{
unsigned long status, dummy = 0;
u32 pfn32;
@@ -424,7 +426,7 @@ static int vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn,

STATS_INC(b->stats.lock);

- *hv_status = status = VMWARE_BALLOON_CMD(LOCK, pfn, dummy, dummy);
+ *hv_status = status = VMWARE_BALLOON_CMD(LOCK, pfn, dummy, *target);
if (vmballoon_check_status(b, status))
return 0;

@@ -434,14 +436,14 @@ static int vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn,
}

static int vmballoon_send_batched_lock(struct vmballoon *b,
- unsigned int num_pages)
+ unsigned int num_pages, unsigned int *target)
{
- unsigned long status, dummy;
+ unsigned long status;
unsigned long pfn = page_to_pfn(b->page);

STATS_INC(b->stats.lock);

- status = VMWARE_BALLOON_CMD(BATCHED_LOCK, pfn, num_pages, dummy);
+ status = VMWARE_BALLOON_CMD(BATCHED_LOCK, pfn, num_pages, *target);
if (vmballoon_check_status(b, status))
return 0;

@@ -454,7 +456,8 @@ static int vmballoon_send_batched_lock(struct vmballoon *b,
* 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)
+static bool vmballoon_send_unlock_page(struct vmballoon *b, unsigned long pfn,
+ unsigned int *target)
{
unsigned long status, dummy = 0;
u32 pfn32;
@@ -465,7 +468,7 @@ static bool vmballoon_send_unlock_page(struct vmballoon *b, unsigned long pfn)

STATS_INC(b->stats.unlock);

- status = VMWARE_BALLOON_CMD(UNLOCK, pfn, dummy, dummy);
+ status = VMWARE_BALLOON_CMD(UNLOCK, pfn, dummy, *target);
if (vmballoon_check_status(b, status))
return true;

@@ -475,14 +478,14 @@ static bool vmballoon_send_unlock_page(struct vmballoon *b, unsigned long pfn)
}

static bool vmballoon_send_batched_unlock(struct vmballoon *b,
- unsigned int num_pages)
+ unsigned int num_pages, unsigned int *target)
{
- unsigned long status, dummy;
+ unsigned long status;
unsigned long pfn = page_to_pfn(b->page);

STATS_INC(b->stats.unlock);

- status = VMWARE_BALLOON_CMD(BATCHED_UNLOCK, pfn, num_pages, dummy);
+ status = VMWARE_BALLOON_CMD(BATCHED_UNLOCK, pfn, num_pages, *target);
if (vmballoon_check_status(b, status))
return true;

@@ -528,12 +531,14 @@ static void vmballoon_pop(struct vmballoon *b)
* refuse list, those refused page are then released at the end of the
* inflation cycle.
*/
-static int vmballoon_lock_page(struct vmballoon *b, unsigned int num_pages)
+static int vmballoon_lock_page(struct vmballoon *b, unsigned int num_pages,
+ unsigned int *target)
{
int locked, hv_status;
struct page *page = b->page;

- locked = vmballoon_send_lock_page(b, page_to_pfn(page), &hv_status);
+ locked = vmballoon_send_lock_page(b, page_to_pfn(page), &hv_status,
+ target);
if (locked > 0) {
STATS_INC(b->stats.refused_alloc);

@@ -567,11 +572,11 @@ static int vmballoon_lock_page(struct vmballoon *b, unsigned int num_pages)
}

static int vmballoon_lock_batched_page(struct vmballoon *b,
- unsigned int num_pages)
+ unsigned int num_pages, unsigned int *target)
{
int locked, i;

- locked = vmballoon_send_batched_lock(b, num_pages);
+ locked = vmballoon_send_batched_lock(b, num_pages, target);
if (locked > 0) {
for (i = 0; i < num_pages; i++) {
u64 pa = vmballoon_batch_get_pa(b->batch_page, i);
@@ -620,11 +625,12 @@ static int vmballoon_lock_batched_page(struct vmballoon *b,
* the host so it can make sure the page will be available for the guest
* to use, if needed.
*/
-static int vmballoon_unlock_page(struct vmballoon *b, unsigned int num_pages)
+static int vmballoon_unlock_page(struct vmballoon *b, unsigned int num_pages,
+ unsigned int *target)
{
struct page *page = b->page;

- if (!vmballoon_send_unlock_page(b, page_to_pfn(page))) {
+ if (!vmballoon_send_unlock_page(b, page_to_pfn(page), target)) {
list_add(&page->lru, &b->pages);
return -EIO;
}
@@ -640,12 +646,12 @@ static int vmballoon_unlock_page(struct vmballoon *b, unsigned int num_pages)
}

static int vmballoon_unlock_batched_page(struct vmballoon *b,
- unsigned int num_pages)
+ unsigned int num_pages, unsigned int *target)
{
int locked, i, ret = 0;
bool hv_success;

- hv_success = vmballoon_send_batched_unlock(b, num_pages);
+ hv_success = vmballoon_send_batched_unlock(b, num_pages, target);
if (!hv_success)
ret = -EIO;

@@ -710,9 +716,7 @@ static void vmballoon_add_batched_page(struct vmballoon *b, int idx,
*/
static void vmballoon_inflate(struct vmballoon *b)
{
- unsigned int goal;
unsigned int rate;
- unsigned int i;
unsigned int allocations = 0;
unsigned int num_pages = 0;
int error = 0;
@@ -735,7 +739,6 @@ static void vmballoon_inflate(struct vmballoon *b)
* slowdown page allocations considerably.
*/

- goal = b->target - b->size;
/*
* Start with no sleep allocation rate which may be higher
* than sleeping allocation rate.
@@ -744,16 +747,17 @@ static void vmballoon_inflate(struct vmballoon *b)
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);
+ __func__, b->target - b->size, rate, b->rate_alloc);

- for (i = 0; i < goal; i++) {
- struct page *page = alloc_page(flags);
+ while (b->size < b->target && num_pages < b->target - b->size) {
+ struct page *page;

if (flags == VMW_PAGE_ALLOC_NOSLEEP)
STATS_INC(b->stats.alloc);
else
STATS_INC(b->stats.sleep_alloc);

+ page = alloc_page(flags);
if (!page) {
if (flags == VMW_PAGE_ALLOC_CANSLEEP) {
/*
@@ -778,7 +782,7 @@ static void vmballoon_inflate(struct vmballoon *b)
*/
b->slow_allocation_cycles = VMW_BALLOON_SLOW_CYCLES;

- if (i >= b->rate_alloc)
+ if (allocations >= b->rate_alloc)
break;

flags = VMW_PAGE_ALLOC_CANSLEEP;
@@ -789,7 +793,7 @@ static void vmballoon_inflate(struct vmballoon *b)

b->ops->add_page(b, num_pages++, page);
if (num_pages == b->batch_max_pages) {
- error = b->ops->lock(b, num_pages);
+ error = b->ops->lock(b, num_pages, &b->target);
num_pages = 0;
if (error)
break;
@@ -800,21 +804,21 @@ static void vmballoon_inflate(struct vmballoon *b)
allocations = 0;
}

- if (i >= rate) {
+ if (allocations >= rate) {
/* We allocated enough pages, let's take a break. */
break;
}
}

if (num_pages > 0)
- b->ops->lock(b, num_pages);
+ b->ops->lock(b, num_pages, &b->target);

/*
* 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;
+ if (error == 0 && allocations >= b->rate_alloc) {
+ unsigned int mult = allocations / b->rate_alloc;

b->rate_alloc =
min(b->rate_alloc + mult * VMW_BALLOON_RATE_ALLOC_INC,
@@ -831,16 +835,11 @@ static void vmballoon_deflate(struct vmballoon *b)
{
struct page *page, *next;
unsigned int i = 0;
- unsigned int goal;
unsigned int num_pages = 0;
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);
+ pr_debug("%s - size: %d, target %d, rate: %d\n", __func__, b->size,
+ b->target, b->rate_free);

/* free pages to reach target */
list_for_each_entry_safe(page, next, &b->pages, lru) {
@@ -848,7 +847,7 @@ static void vmballoon_deflate(struct vmballoon *b)
b->ops->add_page(b, num_pages++, page);

if (num_pages == b->batch_max_pages) {
- error = b->ops->unlock(b, num_pages);
+ error = b->ops->unlock(b, num_pages, &b->target);
num_pages = 0;
if (error) {
/* quickly decrease rate in case of error */
@@ -858,12 +857,12 @@ static void vmballoon_deflate(struct vmballoon *b)
}
}

- if (++i >= goal)
+ if (++i >= b->size - b->target)
break;
}

if (num_pages > 0)
- b->ops->unlock(b, num_pages);
+ b->ops->unlock(b, num_pages, &b->target);

/* slowly increase rate if there were no errors */
if (error == 0)
--
2.4.3