path: root/Documentation/filesystems/tmpfs.txt
diff options
authorRobin Holt <holt@sgi.com>2006-01-14 13:20:48 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-14 18:27:07 -0800
commit7339ff8302fd70aabf5f1ae26e0c4905fa74a495 (patch)
tree38ee561d51b7e4db7c0d6dd9ebd9fc22c2b6ab88 /Documentation/filesystems/tmpfs.txt
parent852cf918dcf2ae46468b425e679fbcbf0ea8fdbb (diff)
[PATCH] Add tmpfs options for memory placement policies
Anything that writes into a tmpfs filesystem is liable to disproportionately decrease the available memory on a particular node. Since there's no telling what sort of application (e.g. dd/cp/cat) might be dropping large files there, this lets the admin choose the appropriate default behavior for their site's situation. Introduce a tmpfs mount option which allows specifying a memory policy and a second option to specify the nodelist for that policy. With the default policy, tmpfs will behave as it does today. This patch adds support for preferred, bind, and interleave policies. The default policy will cause pages to be added to tmpfs files on the node which is doing the writing. Some jobs expect a single process to create and manage the tmpfs files. This results in a node which has a significantly reduced number of free pages. With this patch, the administrator can specify the policy and nodes for that policy where they would prefer allocations. This patch was originally written by Brent Casavant and Hugh Dickins. I added support for the bind and preferred policies and the mpol_nodelist mount option. Signed-off-by: Brent Casavant <bcasavan@sgi.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Robin Holt <holt@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'Documentation/filesystems/tmpfs.txt')
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/filesystems/tmpfs.txt b/Documentation/filesystems/tmpfs.txt
index 0d783c504ead..dbe4d87d2615 100644
--- a/Documentation/filesystems/tmpfs.txt
+++ b/Documentation/filesystems/tmpfs.txt
@@ -78,6 +78,18 @@ 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:
+mpol=interleave prefers to allocate memory from each node in turn
+mpol=default prefers to allocate memory from the local node
+mpol=bind prefers to allocate from mpol_nodelist
+mpol=preferred prefers to allocate from first node in mpol_nodelist
+The following mount option is used in conjunction with mpol=interleave,
+mpol=bind or mpol=preferred:
+mpol_nodelist: nodelist suitable for parsing with nodelist_parse.
To specify the initial root directory you can use the following mount