Re: [PATCH 1/2] x86/mem-sharing: Bulk mem-sharing entire domains

[Tamas K Lengyel <tamas@tklengyel.com>]

[-- Attachment #1.1: Type: text/plain, Size: 2164 bytes --]

>
> > @@ -1467,6 +1503,56 @@ int
> mem_sharing_memop(XEN_GUEST_HANDLE_PARAM(xen_mem_sharing_op_t) arg)
> >          }
> >          break;
> >
> > +        case XENMEM_sharing_op_bulk_dedup:
> > +        {
> > +            unsigned long max_sgfn, max_cgfn;
> > +            struct domain *cd;
> > +
> > +            rc = -EINVAL;
> > +            if ( !mem_sharing_enabled(d) )
> > +                goto out;
> > +
> > +            rc =
> rcu_lock_live_remote_domain_by_id(mso.u.share.client_domain,
> > +                                                   &cd);
> > +            if ( rc )
> > +                goto out;
> > +
> > +            rc = xsm_mem_sharing_op(XSM_DM_PRIV, d, cd, mso.op);
> > +            if ( rc )
> > +            {
> > +                rcu_unlock_domain(cd);
> > +                goto out;
> > +            }
> > +
> > +            if ( !mem_sharing_enabled(cd) )
> > +            {
> > +                rcu_unlock_domain(cd);
> > +                rc = -EINVAL;
> > +                goto out;
> > +            }
> > +
> > +            max_sgfn = domain_get_maximum_gpfn(d);
> > +            max_cgfn = domain_get_maximum_gpfn(cd);
> > +
> > +            if ( max_sgfn != max_cgfn || max_sgfn < start_iter )
> > +            {
> > +                rcu_unlock_domain(cd);
> > +                rc = -EINVAL;
> > +                goto out;
> > +            }
> > +
> > +            rc = bulk_share(d, cd, max_sgfn, start_iter,
> MEMOP_CMD_MASK);
> > +            if ( rc > 0 )
> > +            {
> > +                ASSERT(!(rc & MEMOP_CMD_MASK));
>
> The way other continuations like this work is to shift the remaining
> work left by MEMOP_EXTENT_SHIFT.
>
> This avoids bulk_share() needing to know MEMOP_CMD_MASK, but does chop 6
> bits off the available max_sgfn.
>
> However, a better alternative would be to extend xen_mem_sharing_op and
> stash the continue information in a new union.  That would avoid the
> mask games, and also avoid limiting the maximum potential gfn.
>
> ~Andrew


I agree, I was thinking of extending it anyway to return the number of
pages that was shared, so this could be looped in there too.

Thanks,
Tamas

[-- Attachment #1.2: Type: text/html, Size: 3186 bytes --]

[-- Attachment #2: Type: text/plain, Size: 126 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel