Revision fcf8a1e483490cd249df4e02d5425636c3f43c86 authored by Waiman Long on 12 July 2019, 03:56:38 UTC, committed by Linus Torvalds on 12 July 2019, 18:05:44 UTC
There are concerns about memory leaks from extensive use of memory cgroups as each memory cgroup creates its own set of kmem caches. There is a possiblity that the memcg kmem caches may remain even after the memory cgroups have been offlined. Therefore, it will be useful to show the status of each of memcg kmem caches. This patch introduces a new <debugfs>/memcg_slabinfo file which is somewhat similar to /proc/slabinfo in format, but lists only information about kmem caches that have child memcg kmem caches. Information available in /proc/slabinfo are not repeated in memcg_slabinfo. A portion of a sample output of the file was: # <name> <css_id[:dead]> <active_objs> <num_objs> <active_slabs> <num_slabs> rpc_inode_cache root 13 51 1 1 rpc_inode_cache 48 0 0 0 0 fat_inode_cache root 1 45 1 1 fat_inode_cache 41 2 45 1 1 xfs_inode root 770 816 24 24 xfs_inode 92 22 34 1 1 xfs_inode 88:dead 1 34 1 1 xfs_inode 89:dead 23 34 1 1 xfs_inode 85 4 34 1 1 xfs_inode 84 9 34 1 1 The css id of the memcg is also listed. If a memcg is not online, the tag ":dead" will be attached as shown above. [longman@redhat.com: memcg: add ":deact" tag for reparented kmem caches in memcg_slabinfo] Link: http://lkml.kernel.org/r/20190621173005.31514-1-longman@redhat.com [longman@redhat.com: set the flag in the common code as suggested by Roman] Link: http://lkml.kernel.org/r/20190627184324.5875-1-longman@redhat.com Link: http://lkml.kernel.org/r/20190619171621.26209-1-longman@redhat.com Signed-off-by: Waiman Long <longman@redhat.com> Suggested-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent fb2f2b0
security.c
// SPDX-License-Identifier: GPL-2.0-or-later
/* CacheFiles security management
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/fs.h>
#include <linux/cred.h>
#include "internal.h"
/*
* determine the security context within which we access the cache from within
* the kernel
*/
int cachefiles_get_security_ID(struct cachefiles_cache *cache)
{
struct cred *new;
int ret;
_enter("{%s}", cache->secctx);
new = prepare_kernel_cred(current);
if (!new) {
ret = -ENOMEM;
goto error;
}
if (cache->secctx) {
ret = set_security_override_from_ctx(new, cache->secctx);
if (ret < 0) {
put_cred(new);
pr_err("Security denies permission to nominate security context: error %d\n",
ret);
goto error;
}
}
cache->cache_cred = new;
ret = 0;
error:
_leave(" = %d", ret);
return ret;
}
/*
* see if mkdir and create can be performed in the root directory
*/
static int cachefiles_check_cache_dir(struct cachefiles_cache *cache,
struct dentry *root)
{
int ret;
ret = security_inode_mkdir(d_backing_inode(root), root, 0);
if (ret < 0) {
pr_err("Security denies permission to make dirs: error %d",
ret);
return ret;
}
ret = security_inode_create(d_backing_inode(root), root, 0);
if (ret < 0)
pr_err("Security denies permission to create files: error %d",
ret);
return ret;
}
/*
* check the security details of the on-disk cache
* - must be called with security override in force
* - must return with a security override in force - even in the case of an
* error
*/
int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
struct dentry *root,
const struct cred **_saved_cred)
{
struct cred *new;
int ret;
_enter("");
/* duplicate the cache creds for COW (the override is currently in
* force, so we can use prepare_creds() to do this) */
new = prepare_creds();
if (!new)
return -ENOMEM;
cachefiles_end_secure(cache, *_saved_cred);
/* use the cache root dir's security context as the basis with
* which create files */
ret = set_create_files_as(new, d_backing_inode(root));
if (ret < 0) {
abort_creds(new);
cachefiles_begin_secure(cache, _saved_cred);
_leave(" = %d [cfa]", ret);
return ret;
}
put_cred(cache->cache_cred);
cache->cache_cred = new;
cachefiles_begin_secure(cache, _saved_cred);
ret = cachefiles_check_cache_dir(cache, root);
if (ret == -EOPNOTSUPP)
ret = 0;
_leave(" = %d", ret);
return ret;
}
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