Re: Oops report for the week preceding June 16th, 2008

From: Ingo Molnar
Date: Tue Jun 17 2008 - 11:34:54 EST



* David Miller <davem@xxxxxxxxxxxxx> wrote:

> On the wireless front, I severely doubt... in fact I know because I'm
> looking at every wireless merge going into my tree, that John Linville
> is not holding back new drivers submissions from the current 2.6.26
> tree. Neither is Jeff Garzik for non-wireless net drivers.

i have no gripes about the current situation of wireless in linux-next,
other than it all came 1-2 years too late:

$ for ((v=12; v<27; v++)); do v2=v2.6.$[$v+1]; \
[ $v = 25 ] && v2=linus/master; \
[ $v = 26 ] && v2=linux-next/master; \
echo -n v2.6.$[$v+1]": "; \
git-diff --shortstat -M v2.6.$v..$v2 drivers/net/wireless/; done

v2.6.13: 16 files changed, 1707 insertions(+), 1353 deletions(-)
v2.6.14: 46 files changed, 40734 insertions(+), 756 deletions(-)
v2.6.15: 53 files changed, 8016 insertions(+), 4183 deletions(-)
v2.6.16: 37 files changed, 1818 insertions(+), 2513 deletions(-)
v2.6.17: 64 files changed, 17829 insertions(+), 2214 deletions(-)
v2.6.18: 78 files changed, 11159 insertions(+), 1427 deletions(-)
v2.6.19: 63 files changed, 3441 insertions(+), 1500 deletions(-)
v2.6.20: 58 files changed, 1290 insertions(+), 1028 deletions(-)
v2.6.21: 42 files changed, 729 insertions(+), 678 deletions(-)
v2.6.22: 85 files changed, 18989 insertions(+), 552 deletions(-)
v2.6.23: 42 files changed, 2824 insertions(+), 356 deletions(-)
v2.6.24: 208 files changed, 100960 insertions(+), 4303 deletions(-)
v2.6.25: 227 files changed, 54467 insertions(+), 23126 deletions(-)
-git: 214 files changed, 21940 insertions(+), 34143 deletions(-)
-next: 126 files changed, 13585 insertions(+), 10146 deletions(-)

up to v2.6.24 (released only 4 months ago!) we amassed a huge backlog of
~100+ KLOC wireless changes - there were OSS wireless drivers that
havent been merged for up to 1.5 years.

v2.6.24 was no doubt a huge step in the right direction but it came too
late and we are still suffering from the fallout today as we have not
reached test cycle equilibrium yet: by the time mainline gets the
patches a new large batch comes up, invalidating much of mainline's role
and forcing distros to gamble with (much untested and thus detached from
reality) experimental branches.

That's my main point: when we mess up and dont merge OSS driver code
that was out there in time - and we messed up big time with wireless -
we should admit the screwup and swallow the bitter pill.

I.e. should merge the _full_ pipeline, open up to every developer who is
willing to help with the mess, face instability for a short while until
the dust settles and go for absolutely short turnaround for fixes and
even enhancements - because there's little QA value in the existing
code. Instead of pretending that we are "stable" (in this area of the
kernel) - with a code base that distros end up skipping over.

Have a look at Fedora's kernel-2.6.25.6-24.fc8.src.rpm (which is the
Fedora kernel Arjan referred to and which we are talking about here) to
see how this all ends up in distros in practice:

earth4:/usr/src/redhat/SOURCES> ls -ldt *wireless*

-rw-r--r-- 1 root root 4102957 2008-06-03 23:01 linux-2.6-wireless.patch

(excluding renames: 214 files changed, 21940 insertions, 34143 deletions)

-rw-r--r-- 1 root root 1663540 2008-05-29 20:46 linux-2.6-wireless-pending.patch

(excluding renames: 126 files changed, 13585 insertions, 10146 deletions)

-rw-r--r-- 1 root root 38430 2008-05-29 20:46 linux-2.6-wireless-fixups.patch

linux-2.6-wireless.patch [4 MB patch, 55KLOC flux] is what v2.6.26 will
be in a month or so, and it is already an obsolete, historic version,
compared to what Fedora ships today...

linux-2.6-wireless-pending.patch [1.6 MB patch, 23 KLOC flux] is what is
in linux-next in essence and what will go into v2.6.27. Do you think
Fedora jumped to the linux-next version of wireless because the current
(not even released) mainline version was working so well?

And lets finally admit that this pain is all happening to us because we:

_didnt merge drivers soon enough_

Just about anyone who tried to use 3D and wireless on a Linux PC in the
past 3 years will attest to that, without the need for much background
research ;-)

IMO we are not learning and are repeating history once again, as the
Nouveau situation is building up towards a similar "we didnt merge it in
time" pain point. From kernel-2.6.25.6-24.fc8.src.rpm:

-rw-r--r-- 1 root root 513639 2008-05-22 04:31 nouveau-drm.patch

39 files changed, 13960 insertions(+), 5 deletions(-)

Nouveau has been started in 2006, about two years ago. It's a lot less
painful (not the least it is a lot faster as well) if such things are
developed gradually in mainline.

Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/