On Wed 28-07-21 23:25:07, Feng Tang wrote: > On Wed, Jul 28, 2021 at 11:18:10PM +0800, Tang, Feng wrote: > > On Wed, Jul 28, 2021 at 02:42:26PM +0200, Michal Hocko wrote: > > > On Mon 12-07-21 16:09:30, Feng Tang wrote: > > > > The semantics of MPOL_PREFERRED_MANY is similar to MPOL_PREFERRED, > > > > that it will first try to allocate memory from the preferred node(s), > > > > and fallback to all nodes in system when first try fails. > > > > > > > > Add a dedicated function for it just like 'interleave' policy. > > > > > > > > Link: https://lore.kernel.org/r/20200630212517.308045-9-ben.widawsky@xxxxxxxxx > > > > Suggested-by: Michal Hocko <mhocko@xxxxxxxx> > > > > Co-developed-by: Ben Widawsky <ben.widawsky@xxxxxxxxx> > > > > Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx> > > > > Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx> > > > > > > It would be better to squash this together with the actual user of the > > > function added by the next patch. > > > > Ok, will do > > > > > > --- > > > > mm/mempolicy.c | 19 +++++++++++++++++++ > > > > 1 file changed, 19 insertions(+) > > > > > > > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > > > > index 17b5800b7dcc..d17bf018efcc 100644 > > > > --- a/mm/mempolicy.c > > > > +++ b/mm/mempolicy.c > > > > @@ -2153,6 +2153,25 @@ static struct page *alloc_page_interleave(gfp_t gfp, unsigned order, > > > > return page; > > > > } > > > > > > > > +static struct page *alloc_page_preferred_many(gfp_t gfp, unsigned int order, > > > > + struct mempolicy *pol) > > > > > > We likely want a node parameter to know which one we want to start with > > > for locality. Callers should use policy_node for that. > > > > Yes, locality should be considered, something like this? > > > > int pnid, lnid = numa_node_id(); > > > > if (is_nodeset(lnid, &pol->nodes)) > > pnid = local_nid; > > else > > pnid = first_node(pol->nodes); > > One further thought is, if local node is not in the nodemask, > should we compare the distance of all the nodes in nodemask > to the local node and chose the shortest? Nope, That is zonelist for. Nodemask will do the rest. -- Michal Hocko SUSE Labs
