Commit 21a26d49 authored by Randy Dunlap's avatar Randy Dunlap Committed by Linus Torvalds

[PATCH] hugetlbfs doc. update

Fix typos, spelling, etc., in Doc/vm/hugetlbpage.txt.
Signed-off-by: default avatarRandy Dunlap <rdunlap@xenotime.net>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 64a3ca5f
...@@ -27,7 +27,7 @@ number of free hugetlb pages at any time. It also displays information about ...@@ -27,7 +27,7 @@ number of free hugetlb pages at any time. It also displays information about
the configured hugepage size - this is needed for generating the proper the configured hugepage size - this is needed for generating the proper
alignment and size of the arguments to the above system calls. alignment and size of the arguments to the above system calls.
The output of "cat /proc/meminfo" will have output like: The output of "cat /proc/meminfo" will have lines like:
..... .....
HugePages_Total: xxx HugePages_Total: xxx
...@@ -42,11 +42,11 @@ pages in the kernel. Super user can dynamically request more (or free some ...@@ -42,11 +42,11 @@ pages in the kernel. Super user can dynamically request more (or free some
pre-configured) hugepages. pre-configured) hugepages.
The allocation (or deallocation) of hugetlb pages is possible only if there are The allocation (or deallocation) of hugetlb pages is possible only if there are
enough physically contiguous free pages in system (freeing of hugepages is enough physically contiguous free pages in system (freeing of hugepages is
possible only if there are enough hugetlb pages free that can be transfered possible only if there are enough hugetlb pages free that can be transferred
back to regular memory pool). back to regular memory pool).
Pages that are used as hugetlb pages are reserved inside the kernel and can Pages that are used as hugetlb pages are reserved inside the kernel and cannot
not be used for other purposes. be used for other purposes.
Once the kernel with Hugetlb page support is built and running, a user can Once the kernel with Hugetlb page support is built and running, a user can
use either the mmap system call or shared memory system calls to start using use either the mmap system call or shared memory system calls to start using
...@@ -60,7 +60,7 @@ Use the following command to dynamically allocate/deallocate hugepages: ...@@ -60,7 +60,7 @@ Use the following command to dynamically allocate/deallocate hugepages:
This command will try to configure 20 hugepages in the system. The success This command will try to configure 20 hugepages in the system. The success
or failure of allocation depends on the amount of physically contiguous or failure of allocation depends on the amount of physically contiguous
memory that is preset in system at this time. System administrators may want memory that is preset in system at this time. System administrators may want
to put this command in one of the local rc init file. This will enable the to put this command in one of the local rc init files. This will enable the
kernel to request huge pages early in the boot process (when the possibility kernel to request huge pages early in the boot process (when the possibility
of getting physical contiguous pages is still very high). of getting physical contiguous pages is still very high).
...@@ -78,8 +78,8 @@ the uid and gid of the current process are taken. The mode option sets the ...@@ -78,8 +78,8 @@ the uid and gid of the current process are taken. The mode option sets the
mode of root of file system to value & 0777. This value is given in octal. mode of root of file system to value & 0777. This value is given in octal.
By default the value 0755 is picked. The size option sets the maximum value of 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 memory (huge pages) allowed for that filesystem (/mnt/huge). The size is
rounded down to HPAGE_SIZE. The option nr_inode sets the maximum number of 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_inode options are not inodes that /mnt/huge can use. If the size or nr_inodes options are not
provided on command line then no limits are set. For size and nr_inodes 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 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. An example is given at example, size=2K has the same meaning as size=2048. An example is given at
...@@ -88,7 +88,7 @@ the end of this document. ...@@ -88,7 +88,7 @@ the end of this document.
read and write system calls are not supported on files that reside on hugetlb read and write system calls are not supported on files that reside on hugetlb
file systems. file systems.
A regular chown, chgrp and chmod commands (with right permissions) could be Regular chown, chgrp, and chmod commands (with right permissions) could be
used to change the file attributes on hugetlbfs. used to change the file attributes on hugetlbfs.
Also, it is important to note that no such mount command is required if the Also, it is important to note that no such mount command is required if the
...@@ -96,8 +96,8 @@ applications are going to use only shmat/shmget system calls. Users who ...@@ -96,8 +96,8 @@ applications are going to use only shmat/shmget system calls. Users who
wish to use hugetlb page via shared memory segment should be a member of wish to use hugetlb page via shared memory segment should be a member of
a supplementary group and system admin needs to configure that gid into a supplementary group and system admin needs to configure that gid into
/proc/sys/vm/hugetlb_shm_group. It is possible for same or different /proc/sys/vm/hugetlb_shm_group. It is possible for same or different
applications to use any combination of mmaps and shm* calls. Though the applications to use any combination of mmaps and shm* calls, though the
mount of filesystem will be required for using mmaps. mount of filesystem will be required for using mmap calls.
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