From d33c240d47dab4fd15123d9e73fc8810cbc6ed6a Mon Sep 17 00:00:00 2001 From: Tianyu Lan Date: Sat, 25 Jan 2020 16:50:47 -0500 Subject: [PATCH] hv_balloon: Balloon up according to request page number 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 Signed-off-by: Tianyu Lan Reviewed-by: Michael Kelley Signed-off-by: Sasha Levin --- drivers/hv/hv_balloon.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c index b155d00..a02ce43 100644 --- a/drivers/hv/hv_balloon.c +++ b/drivers/hv/hv_balloon.c @@ -1217,10 +1217,7 @@ 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) > HV_HYP_PAGE_SIZE) return i * alloc_unit; @@ -1258,7 +1255,7 @@ 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) @@ -1273,9 +1270,6 @@ 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 PAGE_SIZE allocations. @@ -1285,14 +1279,13 @@ 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) { -- 2.7.4