2 files changed, 84 insertions, 1 deletions
diff --git a/Documentation/sysctl/ctl_unnumbered.txt b/Documentation/sysctl/ctl_unnumbered.txt
new file mode 100644
index 0000000..23003a8e
--- /dev/null
+++ b/Documentation/sysctl/ctl_unnumbered.txt
@@ -0,0 +1,22 @@
+
+Except for a few extremely rare exceptions user space applications do not use
+the binary sysctl interface.  Instead everyone uses /proc/sys/...  with
+readable ascii names.
+
+Recently the kernel has started supporting setting the binary sysctl value to
+CTL_UNNUMBERED so we no longer need to assign a binary sysctl path to allow
+sysctls to show up in /proc/sys.
+
+Assigning binary sysctl numbers is an endless source of conflicts in sysctl.h,
+breaking of the user space ABI (because of those conflicts), and maintenance
+problems.  A complete pass through all of the sysctl users revealed multiple
+instances where the sysctl binary interface was broken and had gone undetected
+for years.
+
+So please do not add new binary sysctl numbers.  They are unneeded and
+problematic.
+
+If you really need a new binary sysctl number please first merge your sysctl
+into the kernel and then as a separate patch allocate a binary sysctl number.
+
+(ebiederm@xmission.com, June 2007)
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index 1d19256..a0ccc5b 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -31,12 +31,15 @@ Currently, these files are in /proc/sys/vm:
 - min_unmapped_ratio
 - min_slab_ratio
 - panic_on_oom
+- mmap_min_address
+- numa_zonelist_order
 
 ==============================================================
 
 dirty_ratio, dirty_background_ratio, dirty_expire_centisecs,
 dirty_writeback_centisecs, vfs_cache_pressure, laptop_mode,
-block_dump, swap_token_timeout, drop-caches:
+block_dump, swap_token_timeout, drop-caches,
+hugepages_treat_as_movable:
 
 See Documentation/filesystems/proc.txt
 
@@ -216,3 +219,61 @@ above-mentioned.
 The default value is 0.
 1 and 2 are for failover of clustering. Please select either
 according to your policy of failover.
+
+==============================================================
+
+mmap_min_addr
+
+This file indicates the amount of address space  which a user process will
+be restricted from mmaping.  Since kernel null dereference bugs could
+accidentally operate based on the information in the first couple of pages
+of memory userspace processes should not be allowed to write to them.  By
+default this value is set to 0 and no protections will be enforced by the
+security module.  Setting this value to something like 64k will allow the
+vast majority of applications to work correctly and provide defense in depth
+against future potential kernel bugs.
+
+==============================================================
+
+numa_zonelist_order
+
+This sysctl is only for NUMA.
+'where the memory is allocated from' is controlled by zonelists.
+(This documentation ignores ZONE_HIGHMEM/ZONE_DMA32 for simple explanation.
+ you may be able to read ZONE_DMA as ZONE_DMA32...)
+
+In non-NUMA case, a zonelist for GFP_KERNEL is ordered as following.
+ZONE_NORMAL -> ZONE_DMA
+This means that a memory allocation request for GFP_KERNEL will
+get memory from ZONE_DMA only when ZONE_NORMAL is not available.
+
+In NUMA case, you can think of following 2 types of order.
+Assume 2 node NUMA and below is zonelist of Node(0)'s GFP_KERNEL
+
+(A) Node(0) ZONE_NORMAL -> Node(0) ZONE_DMA -> Node(1) ZONE_NORMAL
+(B) Node(0) ZONE_NORMAL -> Node(1) ZONE_NORMAL -> Node(0) ZONE_DMA.
+
+Type(A) offers the best locality for processes on Node(0), but ZONE_DMA
+will be used before ZONE_NORMAL exhaustion. This increases possibility of
+out-of-memory(OOM) of ZONE_DMA because ZONE_DMA is tend to be small.
+
+Type(B) cannot offer the best locality but is more robust against OOM of
+the DMA zone.
+
+Type(A) is called as "Node" order. Type (B) is "Zone" order.
+
+"Node order" orders the zonelists by node, then by zone within each node.
+Specify "[Nn]ode" for zone order
+
+"Zone Order" orders the zonelists by zone type, then by node within each
+zone.  Specify "[Zz]one"for zode order.
+
+Specify "[Dd]efault" to request automatic configuration.  Autoconfiguration
+will select "node" order in following case.
+(1) if the DMA zone does not exist or
+(2) if the DMA zone comprises greater than 50% of the available memory or
+(3) if any node's DMA zone comprises greater than 60% of its local memory and
+    the amount of local memory is big enough.
+
+Otherwise, "zone" order will be selected. Default order is recommended unless
+this is causing problems for your system/application.