The final session of day one of the 2012 Kernel Summit considered
the linux-next tree and a possible complementary tree.
Steven Rostedt stated that he'd like to have a "linux-devel" tree,
which would serve a similar purpose to that once served by Andrew Morton's
"-mm" tree: it would be a place where reasonably stable code sits for a
while for longer testing. He noted that such a tree might be useful for an
API that hasn't yet stabilized, for example. Steven asked whether others
would also be interested in something like this.
Chris Mason questioned whether such a tree could work in
practice. "When your work and my work are together, people blame me
for your bugs and vice versa." Based on experience with a similar
approach in another project, Ben Herrenschmidt noted another problem: people
started developing against that code base instead of the designated
development base (i.e., the creation of a "linux-devel" might cause some
people to develop against that tree instead of linux-next). Tony
Luck noted that the value of a "linux-devel" tree would depend greatly on
how much testing it received, and the sense was that such a tree would
likely see less testing than linux-next, which itself could do
with more testers.
Of course, even if a "linux-devel" tree was considered
worthwhile, the tree would need a maintainer. In response to the question
of how much work was required to maintain linux-next, the
maintainer, Stephen Rothwell, said it required between four and ten hours
per day, depending on the stage in the kernel-release cycle.
In the end, as Steven Rostedt himself noted, the overall response to the
proposal of a "linux-devel" tree was unenthusiastic.
Attention then briefly turned to the linux-next tree. Ted Ts'o
asked: are people happy with how the tree was working? The overall
consensus seemed to be that it was working well. H. Peter Anvin seemed
to sum up the mood, in stating his overall contentment with
linux-next while noting that "the imperfections of
linux-next are reflections of the fact that it is a real-world
Ted asked in a tone that seemed to expect a negative
answer, "does anyone run linux-next in anger on their
development system?", and was a little surprised to see that quite a
number of kernel developers indicated that they do eat their own dog
food, living pretty much continuously on linux-next as the booted kernel
on the work system that they use on a daily basis.
After more than three years, it's clear that
linux-next is by now an essential part of the kernel-development
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