The patch titled
Subject: hugetlbfs: document min_size mount option
has been added to the -mm tree. Its filename is
hugetlbfs-document-min_size-mount-option.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/hugetlbfs-document-min_size-mount-option.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/hugetlbfs-document-min_size-mount-option.patch
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------------------------------------------------------
From: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Subject: hugetlbfs: document min_size mount option
Update documentation for the hugetlbfs min_size mount option.
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: Aneesh Kumar <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/vm/hugetlbpage.txt | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff -puN Documentation/vm/hugetlbpage.txt~hugetlbfs-document-min_size-mount-option Documentation/vm/hugetlbpage.txt
--- a/Documentation/vm/hugetlbpage.txt~hugetlbfs-document-min_size-mount-option
+++ a/Documentation/vm/hugetlbpage.txt
@@ -267,8 +267,8 @@ call, then it is required that system ad
type hugetlbfs:
mount -t hugetlbfs \
- -o uid=<value>,gid=<value>,mode=<value>,size=<value>,nr_inodes=<value> \
- none /mnt/huge
+ -o uid=<value>,gid=<value>,mode=<value>,size=<value>,min_size=<value>, \
+ nr_inodes=<value> none /mnt/huge
This command mounts a (pseudo) filesystem of type hugetlbfs on the directory
/mnt/huge. Any files created on /mnt/huge uses huge pages. The uid and gid
@@ -277,11 +277,18 @@ the uid and gid of the current process a
mode of root of file system to value & 01777. This value is given in octal.
By default the value 0755 is picked. The size option sets the maximum value of
memory (huge pages) allowed for that filesystem (/mnt/huge). The size is
-rounded down to HPAGE_SIZE. The option nr_inodes sets the maximum number of
-inodes that /mnt/huge can use. If the size or nr_inodes option is not
-provided on command line then no limits are set. For size and nr_inodes
-options, you can use [G|g]/[M|m]/[K|k] to represent giga/mega/kilo. For
-example, size=2K has the same meaning as size=2048.
+rounded down to HPAGE_SIZE. The min_size option sets the minimum value of
+memory (huge pages) allowed for the filesystem. Like the size option,
+min_size is rounded down to HPAGE_SIZE. At mount time, the number of huge
+pages specified by min_size are reserved for use by the filesystem. If
+there are not enough free huge pages available, the mount will fail. As
+huge pages are allocated to the filesystem and freed, the reserve count
+is adjusted so that the sum of allocated and reserved huge pages is always
+at least min_size. The option nr_inodes sets the maximum number of
+inodes that /mnt/huge can use. If the size, min_size or nr_inodes option
+is not provided on command line then no limits are set. For size, min_size
+and nr_inodes options, you can use [G|g]/[M|m]/[K|k] to represent
+giga/mega/kilo. For example, size=2K has the same meaning as size=2048.
While read system calls are supported on files that reside on hugetlb
file systems, write system calls are not.
_
Patches currently in -mm which might be from mike.kravetz@xxxxxxxxxx are
hugetlbfs-add-minimum-size-tracking-fields-to-subpool-structure.patch
hugetlbfs-add-minimum-size-tracking-fields-to-subpool-structure-fix.patch
hugetlbfs-add-minimum-size-accounting-to-subpools.patch
hugetlbfs-add-minimum-size-accounting-to-subpools-fix.patch
hugetlbfs-accept-subpool-min_size-mount-option-and-setup-accordingly.patch
hugetlbfs-document-min_size-mount-option.patch
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