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| author | Luiz Capitulino <luizcap@amazon.com> | 2023-09-27 17:25:40 +0300 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2023-10-04 21:47:55 +0300 |
| commit | 9b81d3a5be05d350ac93d99762c7ee91fe29b4cb (patch) | |
| tree | 64610c0ddb9cc6ad96fcb51adb88e170c864cbcb /kernel/cgroup | |
| parent | 105f3fe9188b37752c25d154870ceca352c9213f (diff) | |
| download | linux-9b81d3a5be05d350ac93d99762c7ee91fe29b4cb.tar.xz | |
cgroup: add cgroup_favordynmods= command-line option
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>
Diffstat (limited to 'kernel/cgroup')
| -rw-r--r-- | kernel/cgroup/cgroup.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 833ac6dd15d9..059cd5651d41 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -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 |