[PATCH v6 06/16] memcg: enable accounting for scm_fp_list objects

From: Vasily Averin
Date: Mon Jul 26 2021 - 15:01:13 EST


unix sockets allows to send file descriptors via SCM_RIGHTS type messages.
Each such send call forces kernel to allocate up to 2Kb memory for
struct scm_fp_list.

It makes sense to account for them to restrict the host's memory
consumption from inside the memcg-limited container.

Signed-off-by: Vasily Averin <vvs@xxxxxxxxxxxxx>
---
net/core/scm.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/scm.c b/net/core/scm.c
index ae3085d..5c356f0 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -79,7 +79,7 @@ static int scm_fp_copy(struct cmsghdr *cmsg, struct scm_fp_list **fplp)

if (!fpl)
{
- fpl = kmalloc(sizeof(struct scm_fp_list), GFP_KERNEL);
+ fpl = kmalloc(sizeof(struct scm_fp_list), GFP_KERNEL_ACCOUNT);
if (!fpl)
return -ENOMEM;
*fplp = fpl;
@@ -355,7 +355,7 @@ struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl)
return NULL;

new_fpl = kmemdup(fpl, offsetof(struct scm_fp_list, fp[fpl->count]),
- GFP_KERNEL);
+ GFP_KERNEL_ACCOUNT);
if (new_fpl) {
for (i = 0; i < fpl->count; i++)
get_file(fpl->fp[i]);
--
1.8.3.1