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hv_balloon: Balloon up according to request page number 

commit d33c240d47dab4fd15123d9e73fc8810cbc6ed6a upstream.

Current code has assumption that balloon request memory size aligns
with 2MB. But actually Hyper-V doesn't guarantee such alignment. When
balloon driver receives non-aligned balloon request, it produces warning
and balloon up more memory than requested in order to keep 2MB alignment.
Remove the warning and balloon up memory according to actual requested
memory size.

Fixes: f671223847 ("hv: hv_balloon: avoid memory leak on alloc_error of 2MB memory block")
Cc: stable@vger.kernel.org
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tianyu Lan 2020-01-25 16:50:47 -05:00 committed by Greg Kroah-Hartman
parent 570a29b1f7
commit 385c61a41c
1 changed files with 3 additions and 10 deletions
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13
drivers/hv/hv_balloon.c
View File

@ -1213,10 +1213,7 @@ static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm,
unsigned int i, j;
struct page *pg;
if (num_pages < alloc_unit)
return 0;
for (i = 0; (i * alloc_unit) < num_pages; i++) {
for (i = 0; i < num_pages / alloc_unit; i++) {
if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) >
PAGE_SIZE)
return i * alloc_unit;
@ -1254,7 +1251,7 @@ static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm,
}
return num_pages;
return i * alloc_unit;
}
static void balloon_up(struct work_struct *dummy)
@ -1269,9 +1266,6 @@ static void balloon_up(struct work_struct *dummy)
long avail_pages;
unsigned long floor;
/* The host balloons pages in 2M granularity. */
WARN_ON_ONCE(num_pages % PAGES_IN_2M != 0);
/*
* We will attempt 2M allocations. However, if we fail to
* allocate 2M chunks, we will go back to 4k allocations.
@ -1281,14 +1275,13 @@ static void balloon_up(struct work_struct *dummy)
avail_pages = si_mem_available();
floor = compute_balloon_floor();
/* Refuse to balloon below the floor, keep the 2M granularity. */
/* Refuse to balloon below the floor. */
if (avail_pages < num_pages || avail_pages - num_pages < floor) {
pr_warn("Balloon request will be partially fulfilled. %s\n",
avail_pages < num_pages ? "Not enough memory." :
"Balloon floor reached.");
num_pages = avail_pages > floor ? (avail_pages - floor) : 0;
num_pages -= num_pages % PAGES_IN_2M;
}
while (!done) {