In a fairly short period of time, devtmpfs has gone from a
in May to
being merged into the mainline for 2.6.32. It was merged as an
experimental feature, though, which is something the devtmpfs developers
would like to see change. Kay Sievers posted a
that would remove the
experimental designation as well as make it the default: "All major distros enable devtmpfs on recent systems, so remove
the EXPERIMENTAL flag, and enable it by default to reflect how it
is used today.
Comments on the patch indicate that there is little complaint about
removing the experimental designation, but making it the default was not
particularly popular. Arjan van de Ven complained that enabling devtmpfs by default
violated a kernel convention: "we use 'default y' only for those things
that used to be on, and are now turned into a config option."
Sievers, at least, had never heard of that convention, but is willing to follow it—if it exists.
Alan Cox pointed out that existing
distributions do not use devtmpfs, only those in development, but Sievers
sees no harm for older systems:
And it should not harm any old system if it is enabled. If initramfs
is used it's completely invisible, if a custom kernel with
kernel-mounted rootfs is used, the udev boot script usually
over-mounts the devtmpfs at /dev with an empty tmpfs, like it has
always done it before.
It is unclear whether this change is meant for 2.6.33 or is just being
floated early for the 2.6.34 merge window, but the removal of EXPERIMENTAL
seems to have no real opposition. Whether it becomes the default or not
looks to be up in the air, but in a fairly short period of time, devtmpfs
has cemented its place in the mainline kernel.
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