diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-07-28 17:19:52 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-07-28 17:19:52 -0700 |
commit | 122e7943b252fcf48b4d085dec084e24fc8bec45 (patch) | |
tree | 5d96cbd0311f259009aaf07c026ef86b630ffbfb /Documentation | |
parent | 20d3f2417b41a04510722144eb9a2d7ab53bd75b (diff) | |
parent | 6c54312f9689fbe27c70db5d42eebd29d04b672e (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.rst | 47 |
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 |