[Kernel-packages] [Bug 1533646] Re: Could you set vm.allocate_pgste = 1 by default?

2016-01-21 Thread Dimitri John Ledkov
** Also affects: procps (Ubuntu) Importance: Undecided Status: New ** Changed in: procps (Ubuntu) Status: New => Fix Released ** Changed in: linux (Ubuntu) Status: Incomplete => Invalid -- You received this bug notification because you are a member of Kernel Packages,

[Kernel-packages] [Bug 1533646] Re: Could you set vm.allocate_pgste = 1 by default?

2016-01-21 Thread Viktor Mihajlovski
In my opinion it will be best to set vm.allocate_pgste = 1 unconditionally, regardless of whether qemu is installed or not, and only have the user switch it off for certain memory-intensive workloads (if required at all). -- You received this bug notification because you are a member of Kernel

[Kernel-packages] [Bug 1533646] Re: Could you set vm.allocate_pgste = 1 by default?

2016-01-21 Thread Christian Borntraeger
My modprobe.conf solution might not work in all cases, as the kvm module might be loaded on demand by a process accessing /dev/kvm. That process then already has 2k page tables. So I agree with Viktor: If we want to support KVM, maybe set vm.allocate_pgste = 1 unconditionally. -- You

Re: [Kernel-packages] [Bug 1533646] Re: Could you set vm.allocate_pgste = 1 by default?

2016-01-21 Thread Dimitri John Ledkov
On 21 January 2016 at 08:38, Christian Borntraeger wrote: > ok, kvm builtin certainly makes sense if you plan to use it regularly. > So in essence its a question about: do we expect a number of users to use KVM > in Ubuntu or not? > Yes. Last I checked, on all

[Kernel-packages] [Bug 1533646] Re: Could you set vm.allocate_pgste = 1 by default?

2016-01-21 Thread Christian Borntraeger
ok, kvm builtin certainly makes sense if you plan to use it regularly. So in essence its a question about: do we expect a number of users to use KVM in Ubuntu or not? -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu.

[Kernel-packages] [Bug 1533646] Re: Could you set vm.allocate_pgste = 1 by default?

2016-01-20 Thread Christian Borntraeger
the TCG emulation of QEMU does work without allocatr_pgste. vm.allocate_pgste=1 is necessary to use the KVM kernel module (which is used by qemu in kvm mode) The main difference is that this uses 4k page tables instead of 2k page tables on s390. So enabling pgstes will increase the page table

Re: [Kernel-packages] [Bug 1533646] Re: Could you set vm.allocate_pgste = 1 by default?

2016-01-20 Thread Dimitri John Ledkov
On 20 January 2016 at 19:44, Christian Borntraeger wrote: > the TCG emulation of QEMU does work without allocatr_pgste. > vm.allocate_pgste=1 is necessary to use the KVM kernel module (which is used > by qemu in kvm mode) > > The main difference is that this uses 4k page

[Kernel-packages] [Bug 1533646] Re: Could you set vm.allocate_pgste = 1 by default?

2016-01-19 Thread Dimitri John Ledkov
cool. Is there a way to measure vm.allocate_pgste=1 overheads and is it ok to enable by default? It's needed only on vm hosts... maybe i should add it to the qemu package only? or like try to add systemd hackery to only apply it on bare-metal? (well nested virtualisation is supported...) -- You

[Kernel-packages] [Bug 1533646] Re: Could you set vm.allocate_pgste = 1 by default?

2016-01-15 Thread Tim Gardner
Dimitri - Setting vm.allocate_pgste is a policy decision (which the kernel typically does not make). Is there a good reason not to set it in procps ? There is some extra overhead when vm.allocate_pgste=1. -- You received this bug notification because you are a member of Kernel Packages, which is