Cc: Li Zefan <lizefan@xxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Hillf Danton <dhillf@xxxxxxxxx> Cc: Lennart Poettering <lpoetter@xxxxxxxxxx> Signed-off-by: Aristeu Rozanski <aris@xxxxxxxxxx> --- Documentation/cgroups/00-INDEX | 2 ++ Documentation/cgroups/xattr.txt | 21 +++++++++++++++++++++ 2 files changed, 23 insertions(+) --- a/Documentation/cgroups/00-INDEX 2010-07-29 22:53:28.000000000 -0400 +++ b/Documentation/cgroups/00-INDEX 2012-08-30 12:32:18.419879863 -0400 @@ -16,3 +16,5 @@ memory.txt - Memory Resource Controller; design, accounting, interface, testing. resource_counter.txt - Resource Counter API. +xattr.txt + - Extended attributes support and usage in cgroup filesystem --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ b/Documentation/cgroups/xattr.txt 2012-08-30 13:02:56.585865106 -0400 @@ -0,0 +1,21 @@ +Extended Attributes Usage in cgroup Filesystem + +1. Usage + +cgroup filesystem supports certain types of extended attributes in its +directories and files. The current supported types are: + - Trusted (XATTR_TRUSTED) + - Security (XATTR_SECURITY) + +Both require CAP_SYS_ADMIN capability to set. + +Like in tmpfs, the extended attributes in cgroup filesystem are stored +using kernel memory and it's advised to keep the usage at minimum. This +is the reason why user defined extended attributes are not supported, since +any user can do it and there's no limit in the value size. + +2. Users + +The current known users for this feature are SELinux to limit cgroup usage +in containers and systemd for assorted meta data like main PID in a cgroup +(systemd creates a cgroup per service). -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
