Re: [PATCH v2 6/8] kvm tools: Add rwlock wrapper

Ingo Molnar
2011-05-30T14:11:16Z

* Avi Kivity <avi@redhat.com> wrote:

> On 05/30/2011 03:20 PM, Ingo Molnar wrote:
> >How does this work in practice - i thought we memset() all of RAM
> >during guest kernel bootup. That might have changed with the memblock
> >allocator ... So the guest kernel does not touch all of that 64 GB of
> >RAM, so your box wont OOM straight away?
>
> IIRC there never was a memset() of all RAM, at least since kvm
> started booting Linux. [...]

Hm, bootmem used to do a memset().

> [...] Windows has a zeroing thread which causes all of RAM to be
> committed shortly after boot, though.

heh, maybe they read lkml and copied my ancient idea:

http://people.redhat.com/mingo/clearpage-patches/clearpage-2.3.18-J1

An earlier version had a 'zerod' (page zeroing kernel thread).

This was one of my more stupid ideas btw.

Thanks,

Ingo