path: root/Documentation
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authorLinus Torvalds <torvalds@linux-foundation.org>2013-09-11 16:08:54 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-11 16:08:54 -0700
commitc2d95729e3094ecdd8c54e856bbe971adbbd7f48 (patch)
tree76cc5b551227d3d55d68a93105c1fe8080dfb812 /Documentation
parentbbda1baeeb2f4aff3addac3d086a1e56c3f2503e (diff)
parentb34081f1cd59585451efaa69e1dff1b9507e6c89 (diff)
Merge branch 'akpm' (patches from Andrew Morton)
Merge first patch-bomb from Andrew Morton: - Some pidns/fork/exec tweaks - OCFS2 updates - Most of MM - there remain quite a few memcg parts which depend on pending core cgroups changes. Which might have been already merged - I'll check tomorrow... - Various misc stuff all over the place - A few block bits which I never got around to sending to Jens - relatively minor things. - MAINTAINERS maintenance - A small number of lib/ updates - checkpatch updates - epoll - firmware/dmi-scan - Some kprobes work for S390 - drivers/rtc updates - hfsplus feature work - vmcore feature work - rbtree upgrades - AOE updates - pktcdvd cleanups - PPS - memstick - w1 - New "inittmpfs" feature, which does the obvious - More IPC work from Davidlohr. * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (303 commits) lz4: fix compression/decompression signedness mismatch ipc: drop ipc_lock_check ipc, shm: drop shm_lock_check ipc: drop ipc_lock_by_ptr ipc, shm: guard against non-existant vma in shmdt(2) ipc: document general ipc locking scheme ipc,msg: drop msg_unlock ipc: rename ids->rw_mutex ipc,shm: shorten critical region for shmat ipc,shm: cleanup do_shmat pasta ipc,shm: shorten critical region for shmctl ipc,shm: make shmctl_nolock lockless ipc,shm: introduce shmctl_nolock ipc: drop ipcctl_pre_down ipc,shm: shorten critical region in shmctl_down ipc,shm: introduce lockless functions to obtain the ipc object initmpfs: use initramfs if rootfstype= or root= specified initmpfs: make rootfs use tmpfs when CONFIG_TMPFS enabled initmpfs: move rootfs code from fs/ramfs/ to init/ initmpfs: move bdi setup from init_rootfs to init_ramfs ...
Diffstat (limited to 'Documentation')
11 files changed, 147 insertions, 36 deletions
diff --git a/Documentation/aoe/udev.txt b/Documentation/aoe/udev.txt
index 8686e789542..1f06daf03f5 100644
--- a/Documentation/aoe/udev.txt
+++ b/Documentation/aoe/udev.txt
@@ -23,4 +23,4 @@ SUBSYSTEM=="aoe", KERNEL=="revalidate", NAME="etherd/%k", GROUP="disk", MODE="02
SUBSYSTEM=="aoe", KERNEL=="flush", NAME="etherd/%k", GROUP="disk", MODE="0220"
# aoe block devices
-KERNEL=="etherd*", NAME="%k", GROUP="disk"
+KERNEL=="etherd*", GROUP="disk"
diff --git a/Documentation/block/cmdline-partition.txt b/Documentation/block/cmdline-partition.txt
new file mode 100644
index 00000000000..2bbf4cc40c3
--- /dev/null
+++ b/Documentation/block/cmdline-partition.txt
@@ -0,0 +1,39 @@
+Embedded device command line partition
+Read block device partition table from command line.
+The partition used for fixed block device (eMMC) embedded device.
+It is no MBR, save storage space. Bootloader can be easily accessed
+by absolute address of data on the block device.
+Users can easily change the partition.
+The format for the command line is just like mtdparts:
+ <blkdev-def> := <blkdev-id>:<partdef>[,<partdef>]
+ <partdef> := <size>[@<offset>](part-name)
+ block device disk name, embedded device used fixed block device,
+ it's disk name also fixed. such as: mmcblk0, mmcblk1, mmcblk0boot0.
+ partition size, in bytes, such as: 512, 1m, 1G.
+ partition start address, in bytes.
+ partition name, kernel send uevent with "PARTNAME". application can create
+ a link to block device partition with the name "PARTNAME".
+ user space application can access partition by partition name.
+ eMMC disk name is "mmcblk0" and "mmcblk0boot0"
+ bootargs:
+ 'blkdevparts=mmcblk0:1G(data0),1G(data1),-;mmcblk0boot0:1m(boot),-(kernel)'
+ dmesg:
+ mmcblk0: p1(data0) p2(data1) p3()
+ mmcblk0boot0: p1(boot) p2(kernel)
diff --git a/Documentation/devicetree/bindings/rtc/moxa,moxart-rtc.txt b/Documentation/devicetree/bindings/rtc/moxa,moxart-rtc.txt
new file mode 100644
index 00000000000..c9d3ac1477f
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/moxa,moxart-rtc.txt
@@ -0,0 +1,17 @@
+MOXA ART real-time clock
+Required properties:
+- compatible : Should be "moxa,moxart-rtc"
+- gpio-rtc-sclk : RTC sclk gpio, with zero flags
+- gpio-rtc-data : RTC data gpio, with zero flags
+- gpio-rtc-reset : RTC reset gpio, with zero flags
+ rtc: rtc {
+ compatible = "moxa,moxart-rtc";
+ gpio-rtc-sclk = <&gpio 5 0>;
+ gpio-rtc-data = <&gpio 6 0>;
+ gpio-rtc-reset = <&gpio 7 0>;
+ };
diff --git a/Documentation/devicetree/bindings/rtc/rtc-omap.txt b/Documentation/devicetree/bindings/rtc/rtc-omap.txt
index b47aa415c82..5a0f02d34d9 100644
--- a/Documentation/devicetree/bindings/rtc/rtc-omap.txt
+++ b/Documentation/devicetree/bindings/rtc/rtc-omap.txt
@@ -1,7 +1,11 @@
TI Real Time Clock
Required properties:
-- compatible: "ti,da830-rtc"
+- compatible:
+ - "ti,da830-rtc" - for RTC IP used similar to that on DA8xx SoC family.
+ - "ti,am3352-rtc" - for RTC IP used similar to that on AM335x SoC family.
+ This RTC IP has special WAKE-EN Register to enable
+ Wakeup generation for event Alarm.
- reg: Address range of rtc register set
- interrupts: rtc timer, alarm interrupts in order
- interrupt-parent: phandle for the interrupt controller
diff --git a/Documentation/devicetree/bindings/rtc/rtc-palmas.txt b/Documentation/devicetree/bindings/rtc/rtc-palmas.txt
new file mode 100644
index 00000000000..adbccc0a51e
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/rtc-palmas.txt
@@ -0,0 +1,33 @@
+Palmas RTC controller bindings
+Required properties:
+- compatible:
+ - "ti,palmas-rtc" for palma series of the RTC controller
+- interrupt-parent: Parent interrupt device, must be handle of palmas node.
+- interrupts: Interrupt number of RTC submodule on device.
+Optional properties:
+- ti,backup-battery-chargeable: The Palmas series device like TPS65913 or
+ TPS80036 supports the backup battery for powering the RTC when main
+ battery is removed or in very low power state. The backup battery
+ can be chargeable or non-chargeable. This flag will tells whether
+ battery is chargeable or not. If charging battery then driver can
+ enable the charging.
+- ti,backup-battery-charge-high-current: Enable high current charging in
+ backup battery. Device supports the < 100mA and > 100mA charging.
+ The high current will be > 100mA. Absence of this property will
+ charge battery to lower current i.e. < 100mA.
+ palmas: tps65913@58 {
+ ...
+ palmas_rtc: rtc {
+ compatible = "ti,palmas-rtc";
+ interrupt-parent = <&palmas>;
+ interrupts = <8 0>;
+ ti,backup-battery-chargeable;
+ ti,backup-battery-charge-high-current;
+ };
+ ...
+ };
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index fcc22c982a2..823c95faebd 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -854,16 +854,15 @@ Committed_AS: The amount of memory presently allocated on the system.
The committed memory is a sum of all of the memory which
has been allocated by processes, even if it has not been
"used" by them as of yet. A process which malloc()'s 1G
- of memory, but only touches 300M of it will only show up
- as using 300M of memory even if it has the address space
- allocated for the entire 1G. This 1G is memory which has
- been "committed" to by the VM and can be used at any time
- by the allocating application. With strict overcommit
- enabled on the system (mode 2 in 'vm.overcommit_memory'),
- allocations which would exceed the CommitLimit (detailed
- above) will not be permitted. This is useful if one needs
- to guarantee that processes will not fail due to lack of
- memory once that memory has been successfully allocated.
+ of memory, but only touches 300M of it will show up as
+ using 1G. This 1G is memory which has been "committed" to
+ by the VM and can be used at any time by the allocating
+ application. With strict overcommit enabled on the system
+ (mode 2 in 'vm.overcommit_memory'),allocations which would
+ exceed the CommitLimit (detailed above) will not be permitted.
+ This is useful if one needs to guarantee that processes will
+ not fail due to lack of memory once that memory has been
+ successfully allocated.
VmallocTotal: total size of vmalloc memory area
VmallocUsed: amount of vmalloc area which is used
VmallocChunk: largest contiguous block of vmalloc area which is free
diff --git a/Documentation/filesystems/ramfs-rootfs-initramfs.txt b/Documentation/filesystems/ramfs-rootfs-initramfs.txt
index 59b4a0962e0..b176928e696 100644
--- a/Documentation/filesystems/ramfs-rootfs-initramfs.txt
+++ b/Documentation/filesystems/ramfs-rootfs-initramfs.txt
@@ -79,6 +79,10 @@ to just make sure certain lists can't become empty.
Most systems just mount another filesystem over rootfs and ignore it. The
amount of space an empty instance of ramfs takes up is tiny.
+If CONFIG_TMPFS is enabled, rootfs will use tmpfs instead of ramfs by
+default. To force ramfs, add "rootfstype=ramfs" to the kernel command
What is initramfs?
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index ab7d16efa96..9d4c1d18ad4 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -182,6 +182,7 @@ core_pattern is used to specify a core dumpfile pattern name.
%<NUL> '%' is dropped
%% output one '%'
%p pid
+ %P global pid (init PID namespace)
%u uid
%g gid
%d dump mode, matches PR_SET_DUMPABLE and
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index 36ecc26c743..79a797eb3e8 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -200,17 +200,25 @@ fragmentation index is <= extfrag_threshold. The default value is 500.
-This parameter is only useful when kernelcore= is specified at boot time to
-create ZONE_MOVABLE for pages that may be reclaimed or migrated. Huge pages
-are not movable so are not normally allocated from ZONE_MOVABLE. A non-zero
-value written to hugepages_treat_as_movable allows huge pages to be allocated
-Once enabled, the ZONE_MOVABLE is treated as an area of memory the huge
-pages pool can easily grow or shrink within. Assuming that applications are
-not running that mlock() a lot of memory, it is likely the huge pages pool
-can grow to the size of ZONE_MOVABLE by repeatedly entering the desired value
-into nr_hugepages and triggering page reclaim.
+This parameter controls whether we can allocate hugepages from ZONE_MOVABLE
+or not. If set to non-zero, hugepages can be allocated from ZONE_MOVABLE.
+ZONE_MOVABLE is created when kernel boot parameter kernelcore= is specified,
+so this parameter has no effect if used without kernelcore=.
+Hugepage migration is now available in some situations which depend on the
+architecture and/or the hugepage size. If a hugepage supports migration,
+allocation from ZONE_MOVABLE is always enabled for the hugepage regardless
+of the value of this parameter.
+IOW, this parameter affects only non-migratable hugepages.
+Assuming that hugepages are not migratable in your system, one usecase of
+this parameter is that users can make hugepage pool more extensible by
+enabling the allocation from ZONE_MOVABLE. This is because on ZONE_MOVABLE
+page reclaim/migration/compaction work more and you can get contiguous
+memory more likely. Note that using ZONE_MOVABLE for non-migratable
+hugepages can do harm to other features like memory hotremove (because
+memory hotremove expects that memory blocks on ZONE_MOVABLE are always
+removable,) so it's a trade-off responsible for the users.
diff --git a/Documentation/vm/hugetlbpage.txt b/Documentation/vm/hugetlbpage.txt
index 4ac359b7aa1..bdd4bb97fff 100644
--- a/Documentation/vm/hugetlbpage.txt
+++ b/Documentation/vm/hugetlbpage.txt
@@ -165,6 +165,7 @@ which function as described above for the default huge page-sized case.
Interaction of Task Memory Policy with Huge Page Allocation/Freeing
Whether huge pages are allocated and freed via the /proc interface or
the /sysfs interface using the nr_hugepages_mempolicy attribute, the NUMA
@@ -229,6 +230,7 @@ resulting effect on persistent huge page allocation is as follows:
of huge pages over all on-lines nodes with memory.
Per Node Hugepages Attributes
A subset of the contents of the root huge page control directory in sysfs,
described above, will be replicated under each the system device of each
@@ -258,6 +260,7 @@ applied, from which node the huge page allocation will be attempted.
Using Huge Pages
If the user applications are going to request huge pages using mmap system
call, then it is required that system administrator mount a file system of
@@ -296,20 +299,16 @@ calls, though the mount of filesystem will be required for using mmap calls
without MAP_HUGETLB. For an example of how to use mmap with MAP_HUGETLB see
- * map_hugetlb: see tools/testing/selftests/vm/map_hugetlb.c
- */
+1) map_hugetlb: see tools/testing/selftests/vm/map_hugetlb.c
+2) hugepage-shm: see tools/testing/selftests/vm/hugepage-shm.c
- * hugepage-shm: see tools/testing/selftests/vm/hugepage-shm.c
- */
+3) hugepage-mmap: see tools/testing/selftests/vm/hugepage-mmap.c
- * hugepage-mmap: see tools/testing/selftests/vm/hugepage-mmap.c
- */
+4) The libhugetlbfs (http://libhugetlbfs.sourceforge.net) library provides a
+ wide range of userspace tools to help with huge page usability, environment
+ setup, and control. Furthermore it provides useful test cases that should be
+ used when modifying code to ensure no regressions are introduced.
diff --git a/Documentation/vm/soft-dirty.txt b/Documentation/vm/soft-dirty.txt
index 9a12a5956bc..55684d11a1e 100644
--- a/Documentation/vm/soft-dirty.txt
+++ b/Documentation/vm/soft-dirty.txt
@@ -28,6 +28,13 @@ This is so, since the pages are still mapped to physical memory, and thus all
the kernel does is finds this fact out and puts both writable and soft-dirty
bits on the PTE.
+ While in most cases tracking memory changes by #PF-s is more than enough
+there is still a scenario when we can lose soft dirty bits -- a task
+unmaps a previously mapped memory region and then maps a new one at exactly
+the same place. When unmap is called, the kernel internally clears PTE values
+including soft dirty bits. To notify user space application about such
+memory region renewal the kernel always marks new memory regions (and
+expanded regions) as soft dirty.
This feature is actively used by the checkpoint-restore project. You
can find more details about it on http://criu.org