Re: [PATCH -mm 0/3] fix numa vs kvm scalability issue

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, 19 Feb 2014 09:59:17 +0100 Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Tue, Feb 18, 2014 at 05:12:43PM -0500, riel@xxxxxxxxxx wrote:
> > The NUMA scanning code can end up iterating over many gigabytes
> > of unpopulated memory, especially in the case of a freshly started
> > KVM guest with lots of memory.
> > 
> > This results in the mmu notifier code being called even when
> > there are no mapped pages in a virtual address range. The amount
> > of time wasted can be enough to trigger soft lockup warnings
> > with very large (>2TB) KVM guests.
> > 
> > This patch moves the mmu notifier call to the pmd level, which
> > represents 1GB areas of memory on x86-64. Furthermore, the mmu
> > notifier code is only called from the address in the PMD where
> > present mappings are first encountered.
> > 
> > The hugetlbfs code is left alone for now; hugetlb mappings are
> > not relocatable, and as such are left alone by the NUMA code,
> > and should never trigger this problem to begin with.
> > 
> > The series also adds a cond_resched to task_numa_work, to
> > fix another potential latency issue.
> 
> Andrew, I'll pick up the first kernel/sched/ patch; do you want the
> other two mm/ patches?

That works, thanks.
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux