Re: [Xen-devel] [PATCH 0/4] fix freemem loop

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Thu, 5 Mar 2015, Ian Campbell wrote:
> On Tue, 2015-03-03 at 11:08 +0000, Stefano Stabellini wrote:
> > Hi all,
> > 
> > this patch series fixes the freemem loop on machines with very large
> > amount of memory, where the current wait time is not enough.
> > 
> > In order to be able to handle arbitrarly large amount of ram, we
> > implement in libxl_wait_for_memory_target a policy of waiting until dom0
> > is making progress.
> 
> What is the impact of the libxl API change made here on other callers,
> in particular libvirt?
> 
> If it is expected that existing callers should continue to work as
> before (perhaps with a redundant call etc) then please state this in the
> relevant commit message(s).

The change to libxl_wait_for_memory_target will cause the function to
wait as long as dom0 is ballooning down by any amount of memory in a 2
seconds time frame. Therefore callers might end up waiting for longer
than before, specifically longer than the amount of seconds they pass to
libxl_wait_for_memory_target.

I'll add this message to the relevant commit.


> >   The patch series also reverts "libxl: Wait for
> > ballooning if free memory is increasing", that is not actually
> > implemented correctly.
> > 
> > 
> > Stefano Stabellini (4):
> >       Revert "libxl: Wait for ballooning if free memory is increasing"
> >       libxl_wait_for_memory_target: wait as long as dom0 is making progress
> >       freemem: remove call to libxl_wait_for_free_memory
> >       libxl_wait_for_memory_target: wait for 2 sec at a time
> > 
> >  tools/libxl/libxl.c      |   31 +++++++++++++++++++++++--------
> >  tools/libxl/xl_cmdimpl.c |   29 ++++++-----------------------
> >  2 files changed, 29 insertions(+), 31 deletions(-)
> > 
> > Cheers,
> > 
> > Stefano
> 
> 

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