> -----Original Message----- > From: Xen-devel [mailto:[email protected]] On Behalf Of > Juergen Gross > Sent: 06 September 2017 09:26 > To: [email protected] > Cc: Juergen Gross <[email protected]>; [email protected]; Wei Liu > <[email protected]>; George Dunlap <[email protected]>; > Andrew Cooper <[email protected]>; Ian Jackson > <[email protected]>; Tim (Xen.org) <[email protected]>; > [email protected] > Subject: [Xen-devel] [PATCH v2 5/8] xen: double default grant frame limit for > huge hosts > > In case a system has memory above the 16TB boundary double the default > grant frame number limit per domain. This ensures a pv domain can still > establish the same number of grants even if it is required to use > version 2 grants which need twice the space of v1 grants. > > Signed-off-by: Juergen Gross <[email protected]>
Reviewed-by: Paul Durrant <[email protected]> > --- > xen/common/grant_table.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c > index ae5f1262e8..709fd55490 100644 > --- a/xen/common/grant_table.c > +++ b/xen/common/grant_table.c > @@ -3824,8 +3824,15 @@ static int __init gnttab_usage_init(void) > { > BUILD_BUG_ON(DEFAULT_MAX_MAPTRACK_FRAMES < > DEFAULT_MAX_NR_GRANT_FRAMES); > > + /* > + * In case grant v2 is required for pv domains to reference any possible > + * memory page (i.e. memory is installed above 16TB boundary) double > the > + * grant frame limit. This will allow a guest using v2 grants without > + * having to lower the number of usable grants. > + */ > if ( !max_grant_frames ) > - max_grant_frames = DEFAULT_MAX_NR_GRANT_FRAMES; > + max_grant_frames = ((max_page >> 32) ? 2 : 1) * > + DEFAULT_MAX_NR_GRANT_FRAMES; > > if ( !max_maptrack_frames ) > max_maptrack_frames = DEFAULT_MAX_MAPTRACK_FRAMES; > -- > 2.12.3 > > > _______________________________________________ > Xen-devel mailing list > [email protected] > https://lists.xen.org/xen-devel _______________________________________________ Xen-devel mailing list [email protected] https://lists.xen.org/xen-devel
