tmpfs /dev/shm tmpfs defaults 0 0
Remember to create the directory that you intend to mount tmpfs on
- if necessary (/dev/shm is automagically created if you use devfs).
+ if necessary.
This mount is _not_ needed for SYSV shared memory. The internal
mount is used for that. (In the 2.3 kernel versions it was
nr_blocks: The same as size, but in blocks of PAGE_CACHE_SIZE.
nr_inodes: The maximum number of inodes for this instance. The default
is half of the number of your physical RAM pages, or (on a
- a machine with highmem) the number of lowmem RAM pages,
+ machine with highmem) the number of lowmem RAM pages,
whichever is the lower.
These parameters accept a suffix k, m or g for kilo, mega and giga and
a range being two hyphen-separated decimal numbers, the smallest and
largest node numbers in the range. For example, mpol=bind:0-3,5,7,9-15
+NUMA memory allocation policies have optional flags that can be used in
+conjunction with their modes. These optional flags can be specified
+when tmpfs is mounted by appending them to the mode before the NodeList.
+See Documentation/vm/numa_memory_policy.txt for a list of all available
+memory allocation policy mode flags.
+
+ =static is equivalent to MPOL_F_STATIC_NODES
+ =relative is equivalent to MPOL_F_RELATIVE_NODES
+
+For example, mpol=bind=static:NodeList, is the equivalent of an
+allocation policy of MPOL_BIND | MPOL_F_STATIC_NODES.
+
Note that trying to mount a tmpfs with an mpol option will fail if the
running kernel does not support NUMA; and will fail if its nodelist
-specifies a node >= MAX_NUMNODES. If your system relies on that tmpfs
-being mounted, but from time to time runs a kernel built without NUMA
-capability (perhaps a safe recovery kernel), or configured to support
-fewer nodes, then it is advisable to omit the mpol option from automatic
+specifies a node which is not online. If your system relies on that
+tmpfs being mounted, but from time to time runs a kernel built without
+NUMA capability (perhaps a safe recovery kernel), or with fewer nodes
+online, then it is advisable to omit the mpol option from automatic
mount options. It can be added later, when the tmpfs is already mounted
on MountPoint, by 'mount -o remount,mpol=Policy:NodeList MountPoint'.
Author:
Christoph Rohland <cr@sap.com>, 1.12.01
Updated:
- Hugh Dickins <hugh@veritas.com>, 19 February 2006
+ Hugh Dickins <hugh@veritas.com>, 4 June 2007