[Devel] [PATCH RHEL8 COMMIT] vmalloc: cancel allocation for oom-killed tasks

[Konstantin Khorenko]

The commit is pushed to "branch-rh8-4.18.0-240.1.1.vz8.5.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh8-4.18.0-240.1.1.vz8.5.41
------>
commit c1508630a4b18b18944c3c307b92edf9d4135ad3
Author: Vasily Averin <vvs at virtuozzo.com>
Date:   Fri Jun 11 20:13:10 2021 +0300

    vmalloc: cancel allocation for oom-killed tasks
    
    huge vmalloc allocation can trigger local memcg oom.
    Currently it is ignored and can lead to global oom.
    
    https://jira.sw.ru/browse/PSBM-108091
    
    Signed-off-by: Vasily Averin <vvs at virtuozzo.com>
    Reviewed-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
    
    (cherry-picked from vz7 commit 2eb147cb3573 ("vmalloc: cancel allocation for
    oom-killed tasks"))
    
    https://jira.sw.ru/browse/PSBM-127856
    Signed-off-by: Valeriy Vdovin <valeriy.vdovin at virtuozzo.com>
---
 mm/vmalloc.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 67317fb29b64..05f871f44571 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1762,6 +1762,11 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 	for (i = 0; i < area->nr_pages; i++) {
 		struct page *page;
 
+		if (unlikely(test_thread_flag(TIF_MEMDIE))) {
+			area->nr_pages = i;
+			goto nofail;
+		}
+
 		if (node == NUMA_NO_NODE)
 			page = alloc_page(alloc_mask|highmem_mask);
 		else
@@ -1785,6 +1790,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 	warn_alloc(gfp_mask, NULL,
 			  "vmalloc: allocation failure, allocated %ld of %ld bytes",
 			  (area->nr_pages*PAGE_SIZE), area->size);
+nofail:
 	vfree(area->addr);
 	return NULL;
 }