Hi Michal, Many thanks for reviewing the whole patchset! We will check them. On Wed, Apr 14, 2021 at 03:25:34PM +0200, Michal Hocko wrote: > 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 ...) You are right, no need to change the gfp_mask here. > > @@ -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. Will follow. The "if (mpol->mode != MPOL_BIND && nodemask) { /* AKA MPOL_PREFERRED_MANY *a/ " and "MPOL_MAX + 1" will be replaced in the 12/13 patch. Thanks, Feng > > return page; > -- > Michal Hocko > SUSE Labs
