Re: [PATCH v2 3/4] selftests: cgroup: fix alloc_anon_noexit() instantly freeing memory

On Thu, Apr 7, 2022 at 4:04 PM Yosry Ahmed yosryahmed@google.com wrote:

On Thu, Apr 7, 2022 at 3:43 PM Yosry Ahmed yosryahmed@google.com wrote:

...

Currently, alloc_anon_noexit() calls alloc_anon() which instantly frees the allocated memory. alloc_anon_noexit() is usually used with cg_run_nowait() to run a process in the background that allocates memory. It makes sense for the background process to keep the memory allocated and not instantly free it (otherwise there is no point of running it in the background).

Signed-off-by: Yosry Ahmed yosryahmed@google.com

tools/testing/selftests/cgroup/test_memcontrol.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c index 36ccf2322e21..c1ec71d83af7 100644 --- a/tools/testing/selftests/cgroup/test_memcontrol.c +++ b/tools/testing/selftests/cgroup/test_memcontrol.c @@ -211,13 +211,18 @@ static int alloc_pagecache_50M_noexit(const char *cgroup, void *arg) static int alloc_anon_noexit(const char *cgroup, void *arg) { int ppid = getppid();

•   size_t size = (unsigned long)arg;
  

•   char *buf, *ptr;
  
  

•   if (alloc_anon(cgroup, arg))
  

•           return -1;
  

•   buf = malloc(size);
  

•   for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
  

•           *ptr = 0;
  
    while (getppid() == ppid)
            sleep(1);
  
  

•   printf("Freeing buffer");
  

Hey Andew,

I am very sorry but I left a debugging printf there by mistake. If it's no hassle, do you mind removing it from the patch (assuming I won't need to send a v3 anyway)?

Never mind I already sent v3 and removed it with other fixes.

Thanks!

...

•   free(buf);
    return 0;
  

}

-- 2.35.1.1178.g4f1659d476-goog