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vmw_balloon: refactor change size from vmballoon_work

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The required change in the balloon size is currently computed in
vmballoon_work(), vmballoon_inflate() and vmballoon_deflate(). Refactor
it to simplify the next patches.

Reviewed-by: Xavier Deguillard <xdeguillard@vmware.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nadav Amit 2018-09-20 10:30:15 -07:00 committed by Greg Kroah-Hartman
parent 25acbdd7e7
commit 8b079cd00f
1 changed files with 52 additions and 23 deletions
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75
drivers/misc/vmw_balloon.c
View File

@ -633,6 +633,37 @@ static void vmballoon_add_page(struct vmballoon *b, int idx, struct page *p)
b->page = p;
}
/**
* vmballoon_change - retrieve the required balloon change
*
* @b: pointer for the balloon.
*
* Return: the required change for the balloon size. A positive number
* indicates inflation, a negative number indicates a deflation.
*/
static int64_t vmballoon_change(struct vmballoon *b)
{
int64_t size, target;
size = b->size;
target = b->target;
/*
* We must cast first because of int sizes
* Otherwise we might get huge positives instead of negatives
*/
if (b->reset_required)
return 0;
/* consider a 2MB slack on deflate, unless the balloon is emptied */
if (target < size && size - target < vmballoon_page_size(true) &&
target != 0)
return 0;
return target - size;
}
/*
* 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
@ -644,8 +675,6 @@ static void vmballoon_inflate(struct vmballoon *b)
int error = 0;
bool is_2m_pages;
pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target);
/*
* First try NOSLEEP page allocations to inflate balloon.
*
@ -667,11 +696,8 @@ static void vmballoon_inflate(struct vmballoon *b)
*/
is_2m_pages = b->supported_page_sizes == VMW_BALLOON_NUM_PAGE_SIZES;
pr_debug("%s - goal: %d", __func__, b->target - b->size);
while (!b->reset_required &&
b->size + num_pages * vmballoon_page_size(is_2m_pages)
< b->target) {
while ((int64_t)(num_pages * vmballoon_page_size(is_2m_pages)) <
vmballoon_change(b)) {
struct page *page;
STATS_INC(b->stats.alloc[is_2m_pages]);
@ -742,8 +768,6 @@ static void vmballoon_deflate(struct vmballoon *b)
{
unsigned is_2m_pages;
pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target);
/* free pages to reach target */
for (is_2m_pages = 0; is_2m_pages < b->supported_page_sizes;
is_2m_pages++) {
@ -753,11 +777,9 @@ static void vmballoon_deflate(struct vmballoon *b)
&b->page_sizes[is_2m_pages];
list_for_each_entry_safe(page, next, &page_size->pages, lru) {
if (b->reset_required ||
(b->target > 0 &&
b->size - num_pages
* vmballoon_page_size(is_2m_pages)
< b->target + vmballoon_page_size(true)))
if ((int64_t)(num_pages *
vmballoon_page_size(is_2m_pages)) >=
-vmballoon_change(b))
break;
list_del(&page->lru);
@ -921,28 +943,35 @@ static void vmballoon_reset(struct vmballoon *b)
pr_err("failed to send guest ID to the host\n");
}
/*
* Balloon work function: reset protocol, if needed, get the new size and
* adjust balloon as needed. Repeat in 1 sec.
/**
* vmballoon_work - periodic balloon worker for reset, inflation and deflation.
*
* @work: pointer to the &work_struct which is provided by the workqueue.
*
* Resets the protocol if needed, gets the new size and adjusts 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);
int64_t change = 0;
STATS_INC(b->stats.timer);
if (b->reset_required)
vmballoon_reset(b);
if (!b->reset_required && vmballoon_send_get_target(b)) {
unsigned long target = b->target;
if (vmballoon_send_get_target(b))
change = vmballoon_change(b);
/* update target, adjust size */
if (b->size < target)
if (change != 0) {
pr_debug("%s - size: %u, target %u", __func__,
b->size, b->target);
if (change > 0)
vmballoon_inflate(b);
else if (target == 0 ||
b->size > target + vmballoon_page_size(true))
else /* (change < 0) */
vmballoon_deflate(b);
}