Merge branch 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 cache resource updates from Thomas Gleixner:
 "This update provides updates to RDT:

  - A diagnostic framework for the Resource Director Technology (RDT)
    user interface (sysfs). The failure modes of the user interface are
    hard to diagnose from the error codes. An extra last command status
    file provides now sensible textual information about the failure so
    its simpler to use.

  - A few minor cleanups and updates in the RDT code"

* 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/intel_rdt: Fix a silent failure when writing zero value schemata
  x86/intel_rdt: Fix potential deadlock during resctrl mount
  x86/intel_rdt: Fix potential deadlock during resctrl unmount
  x86/intel_rdt: Initialize bitmask of shareable resource if CDP enabled
  x86/intel_rdt: Remove redundant assignment
  x86/intel_rdt/cqm: Make integer rmid_limbo_count static
  x86/intel_rdt: Add documentation for "info/last_cmd_status"
  x86/intel_rdt: Add diagnostics when making directories
  x86/intel_rdt: Add diagnostics when writing the cpus file
  x86/intel_rdt: Add diagnostics when writing the tasks file
  x86/intel_rdt: Add diagnostics when writing the schemata file
  x86/intel_rdt: Add framework for better RDT UI diagnostics

1 files changed, 11 insertions, 0 deletions

diff --git a/Documentation/x86/intel_rdt_ui.txt b/Documentation/x86/intel_rdt_ui.txt
index 4d8848e4e224..6851854cf69d 100644
--- a/Documentation/x86/intel_rdt_ui.txt
+++ b/Documentation/x86/intel_rdt_ui.txt
@@ -87,6 +87,17 @@ with the following files:
 			bytes) at which a previously used LLC_occupancy
 			counter can be considered for re-use.
 
+Finally, in the top level of the "info" directory there is a file
+named "last_cmd_status". This is reset with every "command" issued
+via the file system (making new directories or writing to any of the
+control files). If the command was successful, it will read as "ok".
+If the command failed, it will provide more information that can be
+conveyed in the error returns from file operations. E.g.
+
+	# echo L3:0=f7 > schemata
+	bash: echo: write error: Invalid argument
+	# cat info/last_cmd_status
+	mask f7 has non-consecutive 1-bits
 
 Resource alloc and monitor groups
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