On Fri, 10 Sep 2010, Mike Snitzer wrote: > On Fri, Sep 10 2010 at 3:05pm -0400, > Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote: > > > > > > > On Fri, 10 Sep 2010, Mike Snitzer wrote: > > > And in fact, this first patch basically is as minimal as it gets > > > relative to bio-based DM's conversion to FLUSH+FUA. > > > > > > Please direct your energy and talent in a positive way rather than > > > starting a potential flame. > > > > > > Thanks, > > > Mike > > > > I don't want to flame. I mean this: > > > > * person X writes a patch P. > > * person Y reads P, sees that the condition C is true and writes patch Q > > that dependes on condition C. > > * person X changes a patch P, so that the patch is correct but condition C > > is no longer true. > > > > Now, there is a bug in the patch Q and NEITHER X NOR Y can find out about > > that bug. > > > > That's why parallel development doesn't work. > > > > If you develop on things in the kernel, it is different. > > * person X writes a patch P and puts it in the kernel. > > * person Y reads the kernel code, sees that the condition C is true and > > writes a patch Q that assumes that the condition C is true. He puts this > > patch to the kernel too. > > * person X wants to change his code so that the condition C isn't true, > > but it is now his responsibility to search the rest of the kernel to see > > if it depends on the condition C. He searches the code and finds Q. > > > > This is not a flamewar, just a technical explanation, why I don't want to > > develop on interfaces that are not in the kernel. > > We're reasonable people and can certainly prevent a flamewar but what > you're doing is an elaborate distraction. The energy it took you to > write and reason through your logic above could've been used to just > review the DM FLUSH+FUA patches. No. If I reviewed 40 patches perfectly, I would take long long time (the previous 2-line patch that I reviewed took me a week to review --- but I found a flaw that the other people who reviewed it quickly didn't find). So I reviewed only "dm" patch and found out that it is too big. Make a smaller patch with barrier -> FLUSH logic only. And then you can make additional patches with function/variable renames or logic changes. > The various interfaces are hardened now and staged for inclussion in > 2.6.37. Jens has already pulled the entire 40+ patchset into his > for-next branch for wider linux-next testing. > > Tejun, Christoph and others have done an amazing job with this > conversion. The fact that Tejun tackled the heavy lifting of DM's > conversion was unexpected but 100% appreciated (by me and I assume > others). Please don't dismiss, or misrepresent the status of, this > FLUSH+FUA work. I am not dismissing anything. I agree with barrier -> flush change. It simplifies things a lot. But I have my work rules that I learned: I use no git kernels and no external patches (except Alasdair's patchset that I want to test). I only use -rc or final kernels. I need a stable computer --- I don't want to solve problems like "does it crash because I pulled something or does it crash because I made a bug in my code?" So, put that into 2.6.37-rc1 and I'll optimize flushes in dm for -rc2 or -rc3. Mikulas -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
