---

yaml
---
r: 129809
b: refs/heads/master
c: 7a6046e
h: refs/heads/master
i:
  129807: 51dde54
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3feeba1e53f54f726a39da254a5c41e02530255e
+refs/heads/master: 7a6046ebe28d6a5d259097dcb44162e5a6eca88e

trunk/CREDITS

@@ -3786,11 +3786,14 @@ S: The Netherlands
 
 N: David Woodhouse
 E: dwmw2@infradead.org
-D: JFFS2 file system, Memory Technology Device subsystem,
+D: ARCnet stuff, Applicom board driver, SO_BINDTODEVICE,
+D: some Alpha platform porting from 2.0, Memory Technology Devices,
+D: Acquire watchdog timer, PC speaker driver maintenance,
 D: various other stuff that annoyed me by not working.
-S: c/o Intel Corporation
-S: Pipers Way
-S: Swindon. SN3 1RJ
+S: c/o Red Hat Engineering
+S: Rustat House
+S: 60 Clifton Road
+S: Cambridge. CB1 7EG
 S: England
 
 N: Chris Wright

trunk/Documentation/DMA-API.txt

@@ -170,15 +170,16 @@ Returns: 0 if successful and a negative error if not.
 u64
 dma_get_required_mask(struct device *dev)
 
-This API returns the mask that the platform requires to
-operate efficiently.  Usually this means the returned mask
+After setting the mask with dma_set_mask(), this API returns the
+actual mask (within that already set) that the platform actually
+requires to operate efficiently.  Usually this means the returned mask
 is the minimum required to cover all of memory.  Examining the
 required mask gives drivers with variable descriptor sizes the
 opportunity to use smaller descriptors as necessary.
 
 Requesting the required mask does not alter the current mask.  If you
-wish to take advantage of it, you should issue a dma_set_mask()
-call to set the mask to the value returned.
+wish to take advantage of it, you should issue another dma_set_mask()
+call to lower the mask again.
 
 
 Part Id - Streaming DMA mappings

trunk/Documentation/accounting/getdelays.c

@@ -392,10 +392,6 @@ int main(int argc, char *argv[])
 			goto err;
 		}
 	}
-	if (!maskset && !tid && !containerset) {
-		usage();
-		goto err;
-	}
 
 	do {
 		int i;

trunk/Documentation/cgroups/cgroups.txt

@@ -1,8 +1,7 @@
 				CGROUPS
 				-------
 
-Written by Paul Menage <menage@google.com> based on
-Documentation/cgroups/cpusets.txt
+Written by Paul Menage <menage@google.com> based on Documentation/cpusets.txt
 
 Original copyright statements from cpusets.txt:
 Portions Copyright (C) 2004 BULL SA.
@@ -69,7 +68,7 @@ On their own, the only use for cgroups is for simple job
 tracking. The intention is that other subsystems hook into the generic
 cgroup support to provide new attributes for cgroups, such as
 accounting/limiting the resources which processes in a cgroup can
-access. For example, cpusets (see Documentation/cgroups/cpusets.txt) allows
+access. For example, cpusets (see Documentation/cpusets.txt) allows
 you to associate a set of CPUs and a set of memory nodes with the
 tasks in each cgroup.
 

trunk/Documentation/cgroups/memcg_test.txt → trunk/Documentation/controllers/memcg_test.txt

@@ -6,7 +6,7 @@ Because VM is getting complex (one of reasons is memcg...), memcg's behavior
 is complex. This is a document for memcg's internal behavior.
 Please note that implementation details can be changed.
 
-(*) Topics on API should be in Documentation/cgroups/memory.txt)
+(*) Topics on API should be in Documentation/controllers/memory.txt)
 
 0. How to record usage ?
    2 objects are used.

trunk/Documentation/filesystems/proc.txt

@@ -1371,8 +1371,292 @@ auto_msgmni default value is 1.
 2.4 /proc/sys/vm - The virtual memory subsystem
 -----------------------------------------------
 
-Please see: Documentation/sysctls/vm.txt for a description of these
-entries.
+The files  in  this directory can be used to tune the operation of the virtual
+memory (VM)  subsystem  of  the  Linux  kernel.
+
+vfs_cache_pressure
+------------------
+
+Controls the tendency of the kernel to reclaim the memory which is used for
+caching of directory and inode objects.
+
+At the default value of vfs_cache_pressure=100 the kernel will attempt to
+reclaim dentries and inodes at a "fair" rate with respect to pagecache and
+swapcache reclaim.  Decreasing vfs_cache_pressure causes the kernel to prefer
+to retain dentry and inode caches.  Increasing vfs_cache_pressure beyond 100
+causes the kernel to prefer to reclaim dentries and inodes.
+
+dirty_background_bytes
+----------------------
+
+Contains the amount of dirty memory at which the pdflush background writeback
+daemon will start writeback.
+
+If dirty_background_bytes is written, dirty_background_ratio becomes a function
+of its value (dirty_background_bytes / the amount of dirtyable system memory).
+
+dirty_background_ratio
+----------------------
+
+Contains, as a percentage of the dirtyable system memory (free pages + mapped
+pages + file cache, not including locked pages and HugePages), the number of
+pages at which the pdflush background writeback daemon will start writing out
+dirty data.
+
+If dirty_background_ratio is written, dirty_background_bytes becomes a function
+of its value (dirty_background_ratio * the amount of dirtyable system memory).
+
+dirty_bytes
+-----------
+
+Contains the amount of dirty memory at which a process generating disk writes
+will itself start writeback.
+
+If dirty_bytes is written, dirty_ratio becomes a function of its value
+(dirty_bytes / the amount of dirtyable system memory).
+
+dirty_ratio
+-----------
+
+Contains, as a percentage of the dirtyable system memory (free pages + mapped
+pages + file cache, not including locked pages and HugePages), the number of
+pages at which a process which is generating disk writes will itself start
+writing out dirty data.
+
+If dirty_ratio is written, dirty_bytes becomes a function of its value
+(dirty_ratio * the amount of dirtyable system memory).
+
+dirty_writeback_centisecs
+-------------------------
+
+The pdflush writeback daemons will periodically wake up and write `old' data
+out to disk.  This tunable expresses the interval between those wakeups, in
+100'ths of a second.
+
+Setting this to zero disables periodic writeback altogether.
+
+dirty_expire_centisecs
+----------------------
+
+This tunable is used to define when dirty data is old enough to be eligible
+for writeout by the pdflush daemons.  It is expressed in 100'ths of a second. 
+Data which has been dirty in-memory for longer than this interval will be
+written out next time a pdflush daemon wakes up.
+
+highmem_is_dirtyable
+--------------------
+
+Only present if CONFIG_HIGHMEM is set.
+
+This defaults to 0 (false), meaning that the ratios set above are calculated
+as a percentage of lowmem only.  This protects against excessive scanning
+in page reclaim, swapping and general VM distress.
+
+Setting this to 1 can be useful on 32 bit machines where you want to make
+random changes within an MMAPed file that is larger than your available
+lowmem without causing large quantities of random IO.  Is is safe if the
+behavior of all programs running on the machine is known and memory will
+not be otherwise stressed.
+
+legacy_va_layout
+----------------
+
+If non-zero, this sysctl disables the new 32-bit mmap mmap layout - the kernel
+will use the legacy (2.4) layout for all processes.
+
+lowmem_reserve_ratio
+---------------------
+
+For some specialised workloads on highmem machines it is dangerous for
+the kernel to allow process memory to be allocated from the "lowmem"
+zone.  This is because that memory could then be pinned via the mlock()
+system call, or by unavailability of swapspace.
+
+And on large highmem machines this lack of reclaimable lowmem memory
+can be fatal.
+
+So the Linux page allocator has a mechanism which prevents allocations
+which _could_ use highmem from using too much lowmem.  This means that
+a certain amount of lowmem is defended from the possibility of being
+captured into pinned user memory.
+
+(The same argument applies to the old 16 megabyte ISA DMA region.  This
+mechanism will also defend that region from allocations which could use
+highmem or lowmem).
+
+The `lowmem_reserve_ratio' tunable determines how aggressive the kernel is
+in defending these lower zones.
+
+If you have a machine which uses highmem or ISA DMA and your
+applications are using mlock(), or if you are running with no swap then
+you probably should change the lowmem_reserve_ratio setting.
+
+The lowmem_reserve_ratio is an array. You can see them by reading this file.
+-
+% cat /proc/sys/vm/lowmem_reserve_ratio
+256     256     32
+-
+Note: # of this elements is one fewer than number of zones. Because the highest
+      zone's value is not necessary for following calculation.
+
+But, these values are not used directly. The kernel calculates # of protection
+pages for each zones from them. These are shown as array of protection pages
+in /proc/zoneinfo like followings. (This is an example of x86-64 box).
+Each zone has an array of protection pages like this.
+
+-
+Node 0, zone      DMA
+  pages free     1355
+        min      3
+        low      3
+        high     4
+	:
+	:
+    numa_other   0
+        protection: (0, 2004, 2004, 2004)
+	^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  pagesets
+    cpu: 0 pcp: 0
+        :
+-
+These protections are added to score to judge whether this zone should be used
+for page allocation or should be reclaimed.
+
+In this example, if normal pages (index=2) are required to this DMA zone and
+pages_high is used for watermark, the kernel judges this zone should not be
+used because pages_free(1355) is smaller than watermark + protection[2]
+(4 + 2004 = 2008). If this protection value is 0, this zone would be used for
+normal page requirement. If requirement is DMA zone(index=0), protection[0]
+(=0) is used.
+
+zone[i]'s protection[j] is calculated by following expression.
+
+(i < j):
+  zone[i]->protection[j]
+  = (total sums of present_pages from zone[i+1] to zone[j] on the node)
+    / lowmem_reserve_ratio[i];
+(i = j):
+   (should not be protected. = 0;
+(i > j):
+   (not necessary, but looks 0)
+
+The default values of lowmem_reserve_ratio[i] are
+    256 (if zone[i] means DMA or DMA32 zone)
+    32  (others).
+As above expression, they are reciprocal number of ratio.
+256 means 1/256. # of protection pages becomes about "0.39%" of total present
+pages of higher zones on the node.
+
+If you would like to protect more pages, smaller values are effective.
+The minimum value is 1 (1/1 -> 100%).
+
+page-cluster
+------------
+
+page-cluster controls the number of pages which are written to swap in
+a single attempt.  The swap I/O size.
+
+It is a logarithmic value - setting it to zero means "1 page", setting
+it to 1 means "2 pages", setting it to 2 means "4 pages", etc.
+
+The default value is three (eight pages at a time).  There may be some
+small benefits in tuning this to a different value if your workload is
+swap-intensive.
+
+overcommit_memory
+-----------------
+
+Controls overcommit of system memory, possibly allowing processes
+to allocate (but not use) more memory than is actually available.
+
+
+0	-	Heuristic overcommit handling. Obvious overcommits of
+		address space are refused. Used for a typical system. It
+		ensures a seriously wild allocation fails while allowing
+		overcommit to reduce swap usage.  root is allowed to
+		allocate slightly more memory in this mode. This is the
+		default.
+
+1	-	Always overcommit. Appropriate for some scientific
+		applications.
+
+2	-	Don't overcommit. The total address space commit
+		for the system is not permitted to exceed swap plus a
+		configurable percentage (default is 50) of physical RAM.
+		Depending on the percentage you use, in most situations
+		this means a process will not be killed while attempting
+		to use already-allocated memory but will receive errors
+		on memory allocation as	appropriate.
+
+overcommit_ratio
+----------------
+
+Percentage of physical memory size to include in overcommit calculations
+(see above.)
+
+Memory allocation limit = swapspace + physmem * (overcommit_ratio / 100)
+
+	swapspace = total size of all swap areas
+	physmem = size of physical memory in system
+
+nr_hugepages and hugetlb_shm_group
+----------------------------------
+
+nr_hugepages configures number of hugetlb page reserved for the system.
+
+hugetlb_shm_group contains group id that is allowed to create SysV shared
+memory segment using hugetlb page.
+
+hugepages_treat_as_movable
+--------------------------
+
+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
+from ZONE_MOVABLE.
+
+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.
+
+laptop_mode
+-----------
+
+laptop_mode is a knob that controls "laptop mode". All the things that are
+controlled by this knob are discussed in Documentation/laptops/laptop-mode.txt.
+
+block_dump
+----------
+
+block_dump enables block I/O debugging when set to a nonzero value. More
+information on block I/O debugging is in Documentation/laptops/laptop-mode.txt.
+
+swap_token_timeout
+------------------
+
+This file contains valid hold time of swap out protection token. The Linux
+VM has token based thrashing control mechanism and uses the token to prevent
+unnecessary page faults in thrashing situation. The unit of the value is
+second. The value would be useful to tune thrashing behavior.
+
+drop_caches
+-----------
+
+Writing to this will cause the kernel to drop clean caches, dentries and
+inodes from memory, causing that memory to become free.
+
+To free pagecache:
+	echo 1 > /proc/sys/vm/drop_caches
+To free dentries and inodes:
+	echo 2 > /proc/sys/vm/drop_caches
+To free pagecache, dentries and inodes:
+	echo 3 > /proc/sys/vm/drop_caches
+
+As this is a non-destructive operation and dirty objects are not freeable, the
+user should run `sync' first.
 
 
 2.5 /proc/sys/dev - Device specific parameters