Please use hugetlb prefix to make it explicit that this is hugetlb related. On Wed 17-03-21 11:40:08, Feng Tang wrote: > From: Ben Widawsky <ben.widawsky@xxxxxxxxx> > > Implement the missing huge page allocation functionality while obeying > the preferred node semantics. > > This uses a fallback mechanism to try multiple preferred nodes first, > and then all other nodes. It cannot use the helper function that was > introduced because huge page allocation already has its own helpers and > it was more LOC, and effort to try to consolidate that. > > The weirdness is MPOL_PREFERRED_MANY can't be called yet because it is > part of the UAPI we haven't yet exposed. Instead of make that define > global, it's simply changed with the UAPI patch. > > [ feng: add NOWARN flag, and skip the direct reclaim to speedup allocation > in some case ] > > Link: https://lore.kernel.org/r/20200630212517.308045-12-ben.widawsky@xxxxxxxxx > Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx> > Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx> > --- > mm/hugetlb.c | 26 +++++++++++++++++++++++--- > mm/mempolicy.c | 3 ++- > 2 files changed, 25 insertions(+), 4 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 8fb42c6..9dfbfa3 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1105,7 +1105,7 @@ static struct page *dequeue_huge_page_vma(struct hstate *h, > unsigned long address, int avoid_reserve, > long chg) > { > - struct page *page; > + struct page *page = NULL; > struct mempolicy *mpol; > gfp_t gfp_mask; > nodemask_t *nodemask; > @@ -1126,7 +1126,17 @@ static struct page *dequeue_huge_page_vma(struct hstate *h, > > gfp_mask = htlb_alloc_mask(h); > nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask); > - page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask); > + if (mpol->mode != MPOL_BIND && nodemask) { /* AKA MPOL_PREFERRED_MANY */ Please use MPOL_PREFERRED_MANY explicitly here. > + gfp_t gfp_mask1 = gfp_mask | __GFP_NOWARN; > + > + gfp_mask1 &= ~__GFP_DIRECT_RECLAIM; > + page = dequeue_huge_page_nodemask(h, > + gfp_mask1, nid, nodemask); > + if (!page) > + page = dequeue_huge_page_nodemask(h, gfp_mask, nid, NULL); > + } else { > + page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask); > + } > if (page && !avoid_reserve && vma_has_reserves(vma, chg)) { > SetHPageRestoreReserve(page); > h->resv_huge_pages--; __GFP_DIRECT_RECLAIM handing is not needed here. dequeue_huge_page_nodemask only uses gfp mask to get zone and cpusets constraines. So the above should have simply been if (mpol->mode == MPOL_PREFERRED_MANY) { page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask); if (page) goto got_page; /* fallback to all nodes */ nodemask = NULL; } page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask); got_page: if (page ...) > @@ -1883,7 +1893,17 @@ struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h, > nodemask_t *nodemask; > > nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask); > - page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask); > + if (mpol->mode != MPOL_BIND && nodemask) { /* AKA MPOL_PREFERRED_MANY */ > + gfp_t gfp_mask1 = gfp_mask | __GFP_NOWARN; > + > + gfp_mask1 &= ~__GFP_DIRECT_RECLAIM; > + page = alloc_surplus_huge_page(h, > + gfp_mask1, nid, nodemask); > + if (!page) > + alloc_surplus_huge_page(h, gfp_mask, nid, NULL); > + } else { > + page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask); > + } And here similar if (mpol->mode == MPOL_PREFERRED_MANY) { page = alloc_surplus_huge_page(h, (gfp_mask | __GFP_NOWARN) & ~(__GFP_DIRECT_RECLAIM), nodemask); if (page) goto got_page; /* fallback to all nodes */ nodemask = NULL; } page = alloc_surplus_huge_page(h, gfp_mask, nodemask); got_page: > mpol_cond_put(mpol); You can have a dedicated gfp mask here if you prefer of course but I calling out MPOL_PREFERRED_MANY explicitly will make the code easier to read. > return page; -- Michal Hocko SUSE Labs
