On Tue, Dec 16, 2014 at 04:41:16PM -0800, Andy Lutomirski wrote: > On Tue, Dec 16, 2014 at 4:00 PM, Linus Torvalds > <torva...@linux-foundation.org> wrote: > > On Tue, Dec 16, 2014 at 3:02 PM, Peter Zijlstra <pet...@infradead.org> > > wrote: > >> > >> OK, should we just stick it in the x86 tree and see if anything > >> explodes? ;-) > > > > Gaah, I got confused about the patches. > > > > And something did explode, it showed some Xen nasties. Xen has that > > odd "we don't share PMD entries between MM's" thing going on, which > > means that the vmalloc fault thing does actually have to occasionally > > walk two levels rather than just copy the top level. I'm still not > > sure why Xen doesn't share PMD's, since threads that shame the MM > > clearly can share PMD's within Xen, but I gave up on it. > > Sounds like it's time to ask Konrad, the source of all Xen understanding :)
Awesome :-) > > Linus, do you have a pointer to whatever version of the patch you tried? The patch was this: a) http://article.gmane.org/gmane.linux.kernel/1835331 Then Jurgen had a patch: https://lkml.kernel.org/g/CA+55aFxSRujj=cM1NkXYvxmo=y1hb1e3tglhdh1jdphzv6w...@mail.gmail.com which was one fix for one bug that ended up being fixed in QEMU - so it can be ignored. But my understanding of that thread was that it said patch 'a)' did not fix Dave's issues - and the conversation went off on NMI watchdog? I will look up the giant thread to make sense. > > --Andy > > > > > That said, making x86-64 use "read_cr3()" instead of > > "current->active_mm" would at least make things a bit safer wrt NMI's > > during the task switch, of course. So *some* 32/64-bit consolidation > > should be done, but my patch went a bit too far for Xen. > > > > Linus > > > > -- > Andy Lutomirski > AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/