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authorLinus Torvalds <torvalds@linux-foundation.org>2023-07-28 17:19:52 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-07-28 17:19:52 -0700
commit122e7943b252fcf48b4d085dec084e24fc8bec45 (patch)
tree5d96cbd0311f259009aaf07c026ef86b630ffbfb /Documentation
parent20d3f2417b41a04510722144eb9a2d7ab53bd75b (diff)
parent6c54312f9689fbe27c70db5d42eebd29d04b672e (diff)
Merge tag 'mm-hotfixes-stable-2023-07-28-15-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull hotfixes from Andrew Morton: "11 hotfixes. Five are cc:stable and the remainder address post-6.4 issues or aren't considered serious enough to justify backporting" * tag 'mm-hotfixes-stable-2023-07-28-15-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: mm/memory-failure: fix hardware poison check in unpoison_memory() proc/vmcore: fix signedness bug in read_from_oldmem() mailmap: update remaining active codeaurora.org email addresses mm: lock VMA in dup_anon_vma() before setting ->anon_vma mm: fix memory ordering for mm_lock_seq and vm_lock_seq scripts/spelling.txt: remove 'thead' as a typo mm/pagewalk: fix EFI_PGT_DUMP of espfix area shmem: minor fixes to splice-read implementation tmpfs: fix Documentation of noswap and huge mount options Revert "um: Use swap() to make code cleaner" mm/damon/core-test: initialise context before test in damon_test_set_attrs()
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/tmpfs.rst47
1 files changed, 20 insertions, 27 deletions
diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst
index f18f46be5c0c..2cd8fa332feb 100644
--- a/Documentation/filesystems/tmpfs.rst
+++ b/Documentation/filesystems/tmpfs.rst
@@ -84,8 +84,6 @@ 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
machine with highmem) the number of lowmem RAM pages,
whichever is the lower.
-noswap Disables swap. Remounts must respect the original settings.
- By default swap is enabled.
========= ============================================================
These parameters accept a suffix k, m or g for kilo, mega and giga and
@@ -99,36 +97,31 @@ mount with such options, since it allows any user with write access to
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 blocks may be swapped out, when there is a shortage of memory.
+tmpfs has a mount option to disable its use of swap:
+
+====== ===========================================================
+noswap Disables swap. Remounts must respect the original settings.
+ By default swap is enabled.
+====== ===========================================================
+
tmpfs also supports Transparent Huge Pages which requires a kernel
configured with CONFIG_TRANSPARENT_HUGEPAGE and with huge supported for
your system (has_transparent_hugepage(), which is architecture specific).
The mount options for this are:
-====== ============================================================
-huge=0 never: disables huge pages for the mount
-huge=1 always: enables huge pages for the mount
-huge=2 within_size: only allocate huge pages if the page will be
- fully within i_size, also respect fadvise()/madvise() hints.
-huge=3 advise: only allocate huge pages if requested with
- fadvise()/madvise()
-====== ============================================================
-
-There is a sysfs file which you can also use to control system wide THP
-configuration for all tmpfs mounts, the file is:
-
-/sys/kernel/mm/transparent_hugepage/shmem_enabled
-
-This sysfs file is placed on top of THP sysfs directory and so is registered
-by THP code. It is however only used to control all tmpfs mounts with one
-single knob. Since it controls all tmpfs mounts it should only be used either
-for emergency or testing purposes. The values you can set for shmem_enabled are:
-
-== ============================================================
--1 deny: disables huge on shm_mnt and all mounts, for
- emergency use
--2 force: enables huge on shm_mnt and all mounts, w/o needing
- option, for testing
-== ============================================================
+================ ==============================================================
+huge=never Do not allocate huge pages. This is the default.
+huge=always Attempt to allocate huge page every time a new page is needed.
+huge=within_size Only allocate huge page if it will be fully within i_size.
+ Also respect madvise(2) hints.
+huge=advise Only allocate huge page if requested with madvise(2).
+================ ==============================================================
+
+See also Documentation/admin-guide/mm/transhuge.rst, which describes the
+sysfs file /sys/kernel/mm/transparent_hugepage/shmem_enabled: which can
+be used to deny huge pages on all tmpfs mounts in an emergency, or to
+force huge pages on all tmpfs mounts for testing.
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