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VMware balloon: Update balloon target on each lock/unlock.
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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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Xavier Deguillard authored and Greg Kroah-Hartman committed Oct 4, 2015
1 parent f220a80 commit 4670de4
Showing 1 changed file with 42 additions and 43 deletions.
85 changes: 42 additions & 43 deletions drivers/misc/vmw_balloon.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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");
Expand Down Expand Up @@ -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 {
Expand Down Expand Up @@ -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;
Expand All @@ -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;

Expand All @@ -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;

Expand All @@ -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;
Expand All @@ -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;

Expand All @@ -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;

Expand Down Expand Up @@ -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);

Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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;
}
Expand All @@ -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;

Expand Down Expand Up @@ -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;
Expand All @@ -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.
Expand All @@ -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) {
/*
Expand All @@ -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;
Expand All @@ -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;
Expand All @@ -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,
Expand All @@ -831,24 +835,19 @@ 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) {
list_del(&page->lru);
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 */
Expand All @@ -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)
Expand Down

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