x86/intel_rdt: Add L2CDP support in documentation

L2 and L3 Code and Data Prioritization (CDP) can be enabled separately.
The existing mount parameter "cdp" is only for enabling L3 CDP and will be
kept for backwards compability.

Add a new mount parameter 'cdpl2' for L2 CDP.

[ tglx: Made changelog readable ]

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: Vikas" <vikas.shivappa@intel.com>
Cc: Sai Praneeth" <sai.praneeth.prakhya@intel.com>
Cc: Reinette" <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/1513810644-78015-3-git-send-email-fenghua.yu@intel.com

Documentation/x86/intel_rdt_ui.txt

@@ -10,18 +10,21 @@ This feature is enabled by the CONFIG_INTEL_RDT Kconfig and the
 X86 /proc/cpuinfo flag bits:
 RDT (Resource Director Technology) Allocation - "rdt_a"
 CAT (Cache Allocation Technology) - "cat_l3", "cat_l2"
-CDP (Code and Data Prioritization ) - "cdp_l3"
+CDP (Code and Data Prioritization ) - "cdp_l3", "cdp_l2"
 CQM (Cache QoS Monitoring) - "cqm_llc", "cqm_occup_llc"
 MBM (Memory Bandwidth Monitoring) - "cqm_mbm_total", "cqm_mbm_local"
 MBA (Memory Bandwidth Allocation) - "mba"
 
 To use the feature mount the file system:
 
- # mount -t resctrl resctrl [-o cdp] /sys/fs/resctrl
+ # mount -t resctrl resctrl [-o cdp[,cdpl2]] /sys/fs/resctrl
 
 mount options are:
 
 "cdp": Enable code/data prioritization in L3 cache allocations.
+"cdpl2": Enable code/data prioritization in L2 cache allocations.
+
+L2 and L3 CDP are controlled seperately.
 
 RDT features are orthogonal. A particular system may support only
 monitoring, only control, or both monitoring and control.