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Diffstat (limited to 'Documentation/filesystems/tmpfs.txt')
| -rw-r--r-- | Documentation/filesystems/tmpfs.txt | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/Documentation/filesystems/tmpfs.txt b/Documentation/filesystems/tmpfs.txt index 0d783c504ead..1773106976a2 100644 --- a/Documentation/filesystems/tmpfs.txt +++ b/Documentation/filesystems/tmpfs.txt @@ -78,6 +78,30 @@ use up all the memory on the machine; but enhances the scalability of that instance in a system with many cpus making intensive use of it. +tmpfs has a mount option to set the NUMA memory allocation policy for +all files in that instance (if CONFIG_NUMA is enabled) - which can be +adjusted on the fly via 'mount -o remount ...' + +mpol=default prefers to allocate memory from the local node +mpol=prefer:Node prefers to allocate memory from the given Node +mpol=bind:NodeList allocates memory only from nodes in NodeList +mpol=interleave prefers to allocate from each node in turn +mpol=interleave:NodeList allocates from each node of NodeList in turn + +NodeList format is a comma-separated list of decimal numbers and ranges, +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 + +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 +mount options. It can be added later, when the tmpfs is already mounted +on MountPoint, by 'mount -o remount,mpol=Policy:NodeList MountPoint'. + + To specify the initial root directory you can use the following mount options: @@ -97,4 +121,4 @@ RAM/SWAP in 10240 inodes and it is only accessible by root. Author: Christoph Rohland <cr@sap.com>, 1.12.01 Updated: - Hugh Dickins <hugh@veritas.com>, 13 March 2005 + Hugh Dickins <hugh@veritas.com>, 19 February 2006 |