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From:   Vasily Averin <vvs@virtuozzo.com>
Subject: [PATCH v5 06/16] memcg: enable accounting for scm_fp_list objects
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     cgroups@vger.kernel.org, Michal Hocko <mhocko@kernel.org>,
        Shakeel Butt <shakeelb@google.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Roman Gushchin <guro@fb.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <CALvZod66KF-8xKB1dyY2twizDE=svE8iXT_nqvsrfWg1a92f4A@mail.gmail.com>
 <cover.1626688654.git.vvs@virtuozzo.com>
Message-ID: <4fe78621-16a8-ebd9-d7f5-f13c52eb36ff@virtuozzo.com>
Date:   Mon, 19 Jul 2021 13:44:56 +0300
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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@virtuozzo.com>
---
 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