linux-kernel - [PATCH mm v3 1/9] memcg: enable accounting for struct cgroup

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <8d20322e-928b-e995-bd5d-0695841c526f@openvz.org>
Date:   Mon, 30 May 2022 14:25:52 +0300
From:   Vasily Averin <vvs@...nvz.org>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     kernel@...nvz.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, Shakeel Butt <shakeelb@...gle.com>,
        Roman Gushchin <roman.gushchin@...ux.dev>,
        Michal Koutný <mkoutny@...e.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Michal Hocko <mhocko@...e.com>,
        Muchun Song <songmuchun@...edance.com>, cgroups@...r.kernel.org
Subject: [PATCH mm v3 1/9] memcg: enable accounting for struct cgroup

Creating each new cgroup allocates 4Kb for struct cgroup. This is the
largest memory allocation in this scenario and is epecially important
for small VMs with 1-2 CPUs.

Common part of the cgroup creation:
Allocs  Alloc   $1*$2   Sum     Allocation
number  size
--------------------------------------------
16  ~   352     5632    5632    KERNFS
1   +   4096    4096    9728    (cgroup_mkdir+0xe4)
1       584     584     10312   (radix_tree_node_alloc.constprop.0+0x89)
1       192     192     10504   (__d_alloc+0x29)
2       72      144     10648   (avc_alloc_node+0x27)
2       64      128     10776   (percpu_ref_init+0x6a)
1       64      64      10840   (memcg_list_lru_alloc+0x21a)
percpu:
1   +   192     192     192     call_site=psi_cgroup_alloc+0x1e
1   +   96      96      288     call_site=cgroup_rstat_init+0x5f
2       12      24      312     call_site=percpu_ref_init+0x23
1       6       6       318     call_site=__percpu_counter_init+0x22

 '+' -- to be accounted,
 '~' -- partially accounted

Accounting of this memory helps to avoid misuse inside memcg-limited
containers.

Signed-off-by: Vasily Averin <vvs@...nvz.org>
Reviewed-by: Roman Gushchin <roman.gushchin@...ux.dev>
Reviewed-by: Michal Koutný <mkoutny@...e.com>
Acked-by: Shakeel Butt <shakeelb@...gle.com>
Reviewed-by: Muchun Song <songmuchun@...edance.com>
---
 kernel/cgroup/cgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 1779ccddb734..1be0f81fe8e1 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -5353,7 +5353,7 @@ static struct cgroup *cgroup_create(struct cgroup *parent, const char *name,
 
 	/* allocate the cgroup and its ID, 0 is reserved for the root */
 	cgrp = kzalloc(struct_size(cgrp, ancestor_ids, (level + 1)),
-		       GFP_KERNEL);
+		       GFP_KERNEL_ACCOUNT);
 	if (!cgrp)
 		return ERR_PTR(-ENOMEM);
 
-- 
2.36.1