I started seeing this behavior somewhere around 3.16 with CONFIG_PREEMPT set. Setting CONFIG_PREEMPT off seems to help. And, yes, it happens on high load (compiling mozilla, xul) and using qemu chroot to compile mesa.
I'm seeing a few persons bisecting already. If you want, I could start bisecting too, but 3.16 was unstable for me as I'm still on reiserfs. Jeff. On Sat, Dec 13, 2014 at 8:44 AM, Linus Torvalds <torva...@linux-foundation.org> wrote: > On Fri, Dec 12, 2014 at 4:34 PM, Sasha Levin <sasha.le...@oracle.com> wrote: >> >> Right, it's virtio-9p. However, virtio-9p acts merely as a proxy to an >> underlying >> tmpfs - so while it's slow, I don't think it's way slower than the average >> disk >> backed ext4. > > I was thinking more in the sense of "how much of the trouble is about > something like tmpfs eating tons of memory when trinity starts doing > random system calls on those files". > > I was also thinking that some of it might be filesystem-specific. We > already *did* see one trace where it was in the loop getting virtio > channel data. Maybe it's actually possible to overwhelm the 9p > filesystem exactly because the backing store is tmpfs, and basically > have a CPU 100% busy handling ring events from the virtual > filesystem.. > > But I'm just flailing.. > > Linus > -- > 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/ -- 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/
