Re: [PATCH 5/6] shmem: update documentation

From: David Hildenbrand
Date: Mon Mar 06 2023 - 09:06:05 EST


On 03.03.23 00:27, Luis Chamberlain wrote:
Update the docs to reflect a bit better why some folks prefer tmpfs
over ramfs and clarify a bit more about the difference between brd
ramdisks.

Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
---
Documentation/filesystems/tmpfs.rst | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst
index 0408c245785e..e77ebdacadd0 100644
--- a/Documentation/filesystems/tmpfs.rst
+++ b/Documentation/filesystems/tmpfs.rst
@@ -13,14 +13,25 @@ everything stored therein is lost.
tmpfs puts everything into the kernel internal caches and grows and
shrinks to accommodate the files it contains and is able to swap
-unneeded pages out to swap space. It has maximum size limits which can
-be adjusted on the fly via 'mount -o remount ...'
-
-If you compare it to ramfs (which was the template to create tmpfs)
-you gain swapping and limit checking. Another similar thing is the RAM
-disk (/dev/ram*), which simulates a fixed size hard disk in physical
-RAM, where you have to create an ordinary filesystem on top. Ramdisks
-cannot swap and you do not have the possibility to resize them.
+unneeded pages out to swap space.

I suppose, in contrast to ramfs, tmpfs also supports THP. Maybe worth adding as well.

Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>

--
Thanks,

David / dhildenb