On Wed 28-07-21 23:18:10, Feng Tang 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); > > page = __alloc_pages(((gfp | __GFP_NOWARN) & ~__GFP_DIRECT_RECLAIM), > order, pnid, &pol->nodes); > if (!page) > page = __alloc_pages(gfp, order, lnid, NULL); > return page; No. I really meant to get a node argument and use it as it is. Your callers already have some node preferences. Usually a local node and as we have a nodemask here then we do not really need to have any special logic here as mentioned in other email. The preferred node will act only as a source for the zone list. -- Michal Hocko SUSE Labs
