tmakin/tegra-linux-noble
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

cgroup: add cgroup_favordynmods= command-line option

Browse Source 
We have a need of using favordynmods with cgroup v1, which doesn't support
changing mount flags during remount. Enabling CONFIG_CGROUP_FAVOR_DYNMODS at
build-time is not an option because we want to be able to selectively
enable it for certain systems.

This commit addresses this by introducing the cgroup_favordynmods=
command-line option. This option works for both cgroup v1 and v2 and also
allows for disabling favorynmods when the kernel built with
CONFIG_CGROUP_FAVOR_DYNMODS=y.

Also, note that when cgroup_favordynmods=true favordynmods is never
disabled in cgroup_destroy_root().

Signed-off-by: Luiz Capitulino <luizcap@amazon.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Luiz Capitulino
2023-09-27 14:25:40 +00:00
committed by Tejun Heo
parent 105f3fe918
commit 9b81d3a5be
2 changed files with 18 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Documentation/admin-guide/kernel-parameters.txt
+4
View File
@@ -580,6 +580,10 @@
named mounts. Specifying both "all" and "named" disables
all v1 hierarchies.
cgroup_favordynmods= [KNL] Enable or Disable favordynmods.
Format: { "true" | "false" }
Defaults to the value of CONFIG_CGROUP_FAVOR_DYNMODS.
cgroup.memory= [KNL] Pass options to the cgroup memory controller.
Format: <string>
nosocket -- Disable socket memory accounting.
kernel/cgroup/cgroup.c
+14 -4
View File
@@ -207,6 +207,8 @@ static u16 have_exit_callback __read_mostly;
static u16 have_release_callback __read_mostly;
static u16 have_canfork_callback __read_mostly;
static bool have_favordynmods __ro_after_init = IS_ENABLED(CONFIG_CGROUP_FAVOR_DYNMODS);
/* cgroup namespace for init task */
struct cgroup_namespace init_cgroup_ns = {
.ns.count = REFCOUNT_INIT(2),
@@ -1350,7 +1352,9 @@ static void cgroup_destroy_root(struct cgroup_root *root)
cgroup_root_count--;
}
cgroup_favor_dynmods(root, false);
if (!have_favordynmods)
cgroup_favor_dynmods(root, false);
cgroup_exit_root_id(root);
cgroup_unlock();
@@ -2245,9 +2249,9 @@ static int cgroup_init_fs_context(struct fs_context *fc)
fc->user_ns = get_user_ns(ctx->ns->user_ns);
fc->global = true;
#ifdef CONFIG_CGROUP_FAVOR_DYNMODS
ctx->flags |= CGRP_ROOT_FAVOR_DYNMODS;
#endif
if (have_favordynmods)
ctx->flags |= CGRP_ROOT_FAVOR_DYNMODS;
return 0;
}
@@ -6766,6 +6770,12 @@ static int __init enable_cgroup_debug(char *str)
}
__setup("cgroup_debug", enable_cgroup_debug);
static int __init cgroup_favordynmods_setup(char *str)
{
return (kstrtobool(str, &have_favordynmods) == 0);
}
__setup("cgroup_favordynmods=", cgroup_favordynmods_setup);
/**
* css_tryget_online_from_dir - get corresponding css from a cgroup dentry
* @dentry: directory dentry of interest