On Mon, 5 Mar 2007 02:50:31 +0100 Adrian Bunk <bunk at stusta.de> wrote: > This email lists some known regressions in 2.6.21-rc2 compared to 2.6.20 > that are not yet fixed in Linus' tree. We seem to have broken an unusually large amount of stuff this time. partial post-mortem: - The ACPICA merge landed in -mm super-late: basically it was in mainline a week afterwards and saw only a single -mm release. Part of the reason for this short period in -mm was that ACPICA had its paws all over x86_64 code and conflicted badly with significant changes in the x86_64 tree. That happens sometimes. But when it does, the mess lands in my lap rather than in the laps of the perpetrators. Lesson: keep the code well-factored so that different subsystems don't soil each others' kennels. - The hrtimers/dynticks stuff is simply hard: timekeeping, low-level x86, even APICs. These are areas in which things break a lot, so churning it was inevitably going to cause problems. Lesson: none, I think. Low-level x86 support is just hard, and changing it breaks things. So that accounts for _some_ of the damage, but I wonder if there's more to it than that.
