diff mbox series

[04/17] memcg: account security cred as well to kmemcg

Message ID 20200104205943.yjTudiqVx%akpm@linux-foundation.org (mailing list archive)
State New, archived
Headers show
Series [01/17] mm/memory_hotplug: shrink zones when offlining memory | expand

Commit Message

Andrew Morton Jan. 4, 2020, 8:59 p.m. UTC 
From: Shakeel Butt <shakeelb@google.com>
Subject: memcg: account security cred as well to kmemcg

The cred_jar kmem_cache is already memcg accounted in the current kernel
but cred->security is not.  Account cred->security to kmemcg.

Recently we saw high root slab usage on our production and on further
inspection, we found a buggy application leaking processes.  Though
that buggy application was contained within its memcg but we observe
much more system memory overhead, couple of GiBs, during that period. 
This overhead can adversely impact the isolation on the system.  One of
source of high overhead, we found was cred->secuity objects, which have
a lifetime of at least the life of the process which allocated them.

Link: http://lkml.kernel.org/r/20191205223721.40034-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Chris Down <chris@chrisdown.name>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/cred.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff mbox series

Patch

--- a/kernel/cred.c~memcg-account-security-cred-as-well-to-kmemcg
+++ a/kernel/cred.c
@@ -223,7 +223,7 @@  struct cred *cred_alloc_blank(void)
 	new->magic = CRED_MAGIC;
 #endif
 
-	if (security_cred_alloc_blank(new, GFP_KERNEL) < 0)
+	if (security_cred_alloc_blank(new, GFP_KERNEL_ACCOUNT) < 0)
 		goto error;
 
 	return new;
@@ -282,7 +282,7 @@  struct cred *prepare_creds(void)
 	new->security = NULL;
 #endif
 
-	if (security_prepare_creds(new, old, GFP_KERNEL) < 0)
+	if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0)
 		goto error;
 	validate_creds(new);
 	return new;
@@ -715,7 +715,7 @@  struct cred *prepare_kernel_cred(struct
 #ifdef CONFIG_SECURITY
 	new->security = NULL;
 #endif
-	if (security_prepare_creds(new, old, GFP_KERNEL) < 0)
+	if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0)
 		goto error;
 
 	put_cred(old);