Merge commit 'a849088aa1' from rmk/fixes into cleanup/io-pci

As Stephen Rothwell reports, a849088aa155 ("ARM: Fix ioremap() of
address zero") from the arm-current tree and commit c2794437091a ("ARM:
Add fixed PCI i/o mapping") from the arm-soc tree conflict in
a nontrivial way in arch/arm/mm/mmu.c.

Rob Herring explains:
The PCI i/o reserved area has a dummy physical address of 0 and
needs to be skipped by ioremap searches. So we don't set
VM_ARM_STATIC_MAPPING to prevent matches by ioremap. The vm_struct
settings don't really matter when we do the real mapping of the
i/o space.

Since commit a849088aa155 is at the start of the fixes branch
in the arm tree, we can merge it into the branch that contains
the other ioremap changes.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 45 insertions, 0 deletions

diff --git a/Documentation/cgroups/hugetlb.txt b/Documentation/cgroups/hugetlb.txt
new file mode 100644
index 000000000000..a9faaca1f029
--- /dev/null
+++ b/Documentation/cgroups/hugetlb.txt
@@ -0,0 +1,45 @@
+HugeTLB Controller
+-------------------
+
+The HugeTLB controller allows to limit the HugeTLB usage per control group and
+enforces the controller limit during page fault. Since HugeTLB doesn't
+support page reclaim, enforcing the limit at page fault time implies that,
+the application will get SIGBUS signal if it tries to access HugeTLB pages
+beyond its limit. This requires the application to know beforehand how much
+HugeTLB pages it would require for its use.
+
+HugeTLB controller can be created by first mounting the cgroup filesystem.
+
+# mount -t cgroup -o hugetlb none /sys/fs/cgroup
+
+With the above step, the initial or the parent HugeTLB group becomes
+visible at /sys/fs/cgroup. At bootup, this group includes all the tasks in
+the system. /sys/fs/cgroup/tasks lists the tasks in this cgroup.
+
+New groups can be created under the parent group /sys/fs/cgroup.
+
+# cd /sys/fs/cgroup
+# mkdir g1
+# echo $$ > g1/tasks
+
+The above steps create a new group g1 and move the current shell
+process (bash) into it.
+
+Brief summary of control files
+
+ hugetlb.<hugepagesize>.limit_in_bytes     # set/show limit of "hugepagesize" hugetlb usage
+ hugetlb.<hugepagesize>.max_usage_in_bytes # show max "hugepagesize" hugetlb  usage recorded
+ hugetlb.<hugepagesize>.usage_in_bytes     # show current res_counter usage for "hugepagesize" hugetlb
+ hugetlb.<hugepagesize>.failcnt		   # show the number of allocation failure due to HugeTLB limit
+
+For a system supporting two hugepage size (16M and 16G) the control
+files include:
+
+hugetlb.16GB.limit_in_bytes
+hugetlb.16GB.max_usage_in_bytes
+hugetlb.16GB.usage_in_bytes
+hugetlb.16GB.failcnt
+hugetlb.16MB.limit_in_bytes
+hugetlb.16MB.max_usage_in_bytes
+hugetlb.16MB.usage_in_bytes
+hugetlb.16MB.failcnt