[RFC v2][PATCH 2/3] docs: xl interface usage for NUMA-aware ballooning

[Yechen Li <lccycc123@gmail.com>]

this patch contains two docs that describe the changing of
libxl to implement NUMA-aware ballooning.

in docs/man/xl.pod.1, xl mem-set command is expanded to accept
the specified physical node id, and where memory operation is
allow on the other physical NUMA nodes.
XXX: not sure the form is correct. please review and send feedback
if it's wrong.

in docs/misc/xenstore-paths.markdown, describe the new xen-store
path: ~/memory/target_nid, for passing new parameters to balloon.

Signed-off-by: Yechen Li <lccycc123@gmail.com>
---
 docs/man/xl.pod.1                 | 21 ++++++++++++++++++++-
 docs/misc/xenstore-paths.markdown | 11 +++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/docs/man/xl.pod.1 b/docs/man/xl.pod.1
index 5975d7b..c267caa 100644
--- a/docs/man/xl.pod.1
+++ b/docs/man/xl.pod.1
@@ -349,12 +349,31 @@ for bytes.
 The mem-max value may not correspond to the actual memory used in the
 domain, as it may balloon down its memory to give more back to the OS.
 
-=item B<mem-set> I<domain-id> I<mem>
+=item B<mem-set> [I<Options>] I<domain-id> I<mem>
 
 Set the domain's used memory using the balloon driver; append 't' for
 terabytes, 'g' for gigabytes, 'm' for megabytes, 'k' for kilobytes and 'b' for
 bytes.
 
+B<OPTIONS>
+
+=over 4
+
+=item B<-n> I<node-id>
+
+Memory for this ballooning operation to happen should be taken (if
+ballooning up) or freed (if ballooning down) from the host NUMA node
+I<node-id>
+
+=item B<-e>
+
+Only allowed if <-n node-id> is present. If specified, it means that the
+ballooning driver is allowed to use I<node-id> only, for the ballooning
+operation. If not specified, memory from other host NUMA node can be
+used too.
+
+=back
+
 Because this operation requires cooperation from the domain operating
 system, there is no guarantee that it will succeed.  This command will
 definitely not work unless the domain has the required paravirt
diff --git a/docs/misc/xenstore-paths.markdown b/docs/misc/xenstore-paths.markdown
index 1c634b5..4d15b93 100644
--- a/docs/misc/xenstore-paths.markdown
+++ b/docs/misc/xenstore-paths.markdown
@@ -137,6 +137,17 @@ The current balloon target for the domain. The balloon driver within
 the guest is expected to make every effort to every effort use no more
 than this amount of RAM.
 
+#### ~/memory/target_nid = {nodeid nodeexact} []
+
+This path saves balloon target node id and whether memory operation 
+should be taken only on this node. 
+if nodeexact = false, then memory operation can be taken on the other
+host NUMA nodes.
+NOTICE: always change the value of this path before ~/memory/target!
+It's for numa-awareness balloon. See 
+    docs/misc/numa-aware-ballooning.markdown
+for more details.
+
 #### ~/memory/videoram = MEMKB [HVM,INTERNAL]
 
 The size of the video RAM this domain is configured with.
-- 
1.8.1.4