From: Tianyu Lan Tianyu.Lan@microsoft.com
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: f6712238471a ("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
--- drivers/hv/hv_balloon.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-)
--- a/drivers/hv/hv_balloon.c +++ b/drivers/hv/hv_balloon.c @@ -1170,10 +1170,7 @@ static unsigned int alloc_balloon_pages( unsigned int i = 0; 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; @@ -1207,7 +1204,7 @@ static unsigned int alloc_balloon_pages(
}
- return num_pages; + return i * alloc_unit; }
static void balloon_up(struct work_struct *dummy) @@ -1222,9 +1219,6 @@ static void balloon_up(struct work_struc 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. @@ -1234,14 +1228,13 @@ static void balloon_up(struct work_struc 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) {