Re: [Xen-devel] [PATCH 2/2] libxc: fix PV vNUMA guest memory allocation

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Mon, Jul 06, 2015 at 02:26:37PM +0100, Andrew Cooper wrote:
> On 06/07/15 14:17, Wei Liu wrote:
> > In 415b58c1 (tools/libxc: Batch memory allocations for PV guests) the
> > number of super pages is calculated with the number of total pages. That
> > is wrong. It breaks PV guest vNUMA. The correct number of super pages
> > should be derived from the number of pages within that virtual NUMA
> > node.
> >
> > Also change the name and type of super page variable to match the naming
> > convention and type of normal page variable. Make the necessary
> > adjustment to make code compile.
> >
> > Reported-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
> > Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> > ---
> > Cc: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
> > ---
> >  tools/libxc/xc_dom_x86.c | 10 +++++-----
> >  1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/tools/libxc/xc_dom_x86.c b/tools/libxc/xc_dom_x86.c
> > index acd7b3f..faabe96 100644
> > --- a/tools/libxc/xc_dom_x86.c
> > +++ b/tools/libxc/xc_dom_x86.c
> > @@ -879,9 +879,8 @@ int arch_setup_meminit(struct xc_dom_image *dom)
> >          for ( i = 0; i < nr_vmemranges; i++ )
> >          {
> >              unsigned int memflags;
> > -            uint64_t pages;
> > +            uint64_t pages, super_pages;
> >              unsigned int pnode = vnode_to_pnode[vmemranges[i].nid];
> > -            int nr_spages = dom->total_pages >> SUPERPAGE_PFN_SHIFT;
> >              xen_pfn_t extents[SUPERPAGE_BATCH_SIZE];
> >              xen_pfn_t pfn_base_idx;
> >  
> > @@ -891,15 +890,16 @@ int arch_setup_meminit(struct xc_dom_image *dom)
> >  
> >              pages = (vmemranges[i].end - vmemranges[i].start)
> >                  >> PAGE_SHIFT;
> > +            super_pages = pages >> SUPERPAGE_PFN_SHIFT;
> >              pfn_base = vmemranges[i].start >> PAGE_SHIFT;
> >  
> >              for ( pfn = pfn_base; pfn < pfn_base+pages; pfn++ )
> >                  dom->p2m_host[pfn] = pfn;
> >  
> >              pfn_base_idx = pfn_base;
> > -            while (nr_spages) {
> > -                int count = min(nr_spages, SUPERPAGE_BATCH_SIZE);
> > -                nr_spages -= count;
> > +            while (super_pages) {
> > +                int count = min_t(uint64_t, super_pages, 
> > SUPERPAGE_BATCH_SIZE);
> 
> This line alone indicates that int is not an appropriate type for
> count.  unsigned int as as an absolute minimum, as it will be bounded to
> SUPERPAGE_BATCH_SIZE.
> 

Yes, I also need to make count uint64_t.

Wei.

> ~Andrew
> 
> > +                super_pages -= count;
> >  
> >                  for ( pfn = pfn_base_idx, j = 0;
> >                        pfn < pfn_base_idx + (count << SUPERPAGE_PFN_SHIFT);

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