[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] tools/libxc: Avoid hypercalls for cacheflush on x86
On 03/03/14 14:37, Andrew Cooper wrote: > XEN_DOMCTL_cacheflush hypercalls are -ENOSYS on x86. As domain > creation/migration is already very hypercall-heavy, avoid making extra > redundant hypercalls > > Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> > CC: Ian Campbell <Ian.Campbell@xxxxxxxxxx> > CC: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx> > > --- > > Discovered when running valgrind against XenServer trunk, which is now 4.4 > based. > --- > tools/libxc/xc_domain.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c > index 369c3f3..b9cc1db 100644 > --- a/tools/libxc/xc_domain.c > +++ b/tools/libxc/xc_domain.c > @@ -51,12 +51,18 @@ int xc_domain_create(xc_interface *xch, > int xc_domain_cacheflush(xc_interface *xch, uint32_t domid, > xen_pfn_t start_pfn, xen_pfn_t nr_pfns) > { > +#if defined (__i386__) || defined (__x86_64__) > + /* This is not implemented or needed for x86. Avoid repeatedly going to > + * Xen to find -ENOSYS. */ > + return -ENOSYS; > +#else > DECLARE_DOMCTL; > domctl.cmd = XEN_DOMCTL_cacheflush; > domctl.domain = (domid_t)domid; > domctl.u.cacheflush.start_pfn = start_pfn; > domctl.u.cacheflush.nr_pfns = nr_pfns; > return do_domctl(xch, &domctl); > +#endif Rather than icky #ifdef's I suggest caching the result of any -ENOSYS return value. David _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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