The second IRC discussion on the 2.6 "must fix" list was held on
May 21. The full transcript is
available for those who are interested. Below is a quick summary of some
of the high points.
Power management. Patrick Mochel is in a debugging stage;
in any case, power management changes could go in after 2.6.0.
Frame buffer restore after suspending, lots of pending issues, especially
on 3d systems. "It's gonna be hell and will take time." Not
necessarily a show stopper for 2.6.0.
IDE suspend/resume: patches exist which put suspend and
resume operations on request queues so they are properly serialized
with other activity.
I/O scheduler selection; some way of choosing between I/O
schedulers is needed before the new schedulers can be merged. The
anticipatory scheduler still has enough problems on some loads that it
cannot go in otherwise.
qlogic drivers: several exist, none really work. Consensus
seems to be that the "feral" driver is the one to go forward with.
Crypto loopback driver, would be nice for 2.6, but nobody
seems to be working on it.
ext3 big kernel lock removal: Patches exist, but some "deep
surgery" is required to make it all work. There are concerns that
none of the Linux journaling filesystems perform all that well on SMP
systems.
ext2 and ext3 block allocations: the filesystems can allocate
blocks poorly. Not necessarily a 2.6.0 issue.
IRQ balancing, mostly a question of whether the user space
tools should be bundled with the kernel. What's really needed,
perhaps, is a better distribution mechanism for user-space kernel
tools.
klibc: was awaiting users before it could be merged into 2.5,
but those users have not yet materialized. Alexander Viro has things
that would use it, so this work may move forward before 2.6.
kexec (booting one kernel directly from another): is working,
but "seems intrusive and late." It's very useful for some users,
though.
Object-based reverse mapping VM: it still has issues with
highly-shared pages and nonlinear mappings. The latter problem has
been solved. Some think that, if objrmap is merged at all, it should
be marked experimental.
Networking: Andrew says "net/ is boring, it just works all the
time."
Early console/printk and a general API for reporting errors to
user space. This stuff looks too late and slow to get in this time
around.
Kbuild: a better way of building external modules, and allowing
separate source and object directories. "Both sound important."
Conclusion was that it will happen, but it could be after 2.6.0.
Firmware loading: Greg KH pointed out the driver model firmware
interface currently in patch form (see this
LWN article). Should be merged soon.
ACPI: still has problems, but work is proceeding.
Asynchronous I/O: I/O to files still is not truly
asynchronous. Patches exist, but are "late, a bit intrusive, a bit
messy." People think they are important, however; work will be done
to clean them up.
No further discussions have been scheduled at this time.
