Re: [PATCH] mm/hugetlb: Concentrated releases memory when cmdline specifies node requests for large pages
From: Su Hua
Date: Sat Oct 12 2024 - 03:00:42 EST
It does seem to be for a newly allocated huge page just call
enqueue_hugetlb_folio without the complicated decisions in
free_huge_folio.
Thanks
Su
Muchun Song <muchun.song@xxxxxxxxx> 于2024年10月12日周六 11:23写道：
>
>
>
> > On Oct 11, 2024, at 16:05, suhua <suhua.tanke@xxxxxxxxx> wrote:
> >
> > When HVO is enabled and huge page memory allocs are made, the freed memory
> > can be aggregated into higher order memory in the following paths, which
> > facilitates further allocs for higher order memory.
> >
> > echo 200000 > /proc/sys/vm/nr_hugepages
> > echo 200000 > /sys/devices/system/node/node*/hugepages/hugepages-2048kB/nr_hugepages
> > grub： default_hugepagesz=2M hugepagesz=2M hugepages=200000
> >
> > Currently not support for releasing aggregations to higher order in the
> > following way, which will releasing to lower order.
> >
> > grub: default_hugepagesz=2M hugepagesz=2M hugepages=0:100000,1:100000
> >
> > This patch supports the release of huge page optimizations aggregates to
> > higher order memory.
> >
> > eg:
> > cat /proc/cmdline
> > BOOT_IMAGE=/boot/vmlinuz-xxx ... default_hugepagesz=2M hugepagesz=2M hugepages=0:100000,1:100000
> >
> > Before:
> > Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10
> > ...
> > Node 0, zone Normal, type Unmovable 55282 97039 99307 0 1 1 0 1 1 1 0
> > Node 0, zone Normal, type Movable 25 11 345 87 48 21 2 20 9 3 75061
> > Node 0, zone Normal, type Reclaimable 4 2 2 4 3 0 2 1 1 1 0
> > Node 0, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
> > ...
> > Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10
> > Node 1, zone Normal, type Unmovable 98888 99650 99679 2 3 1 2 2 2 0 0
> > Node 1, zone Normal, type Movable 1 1 0 1 1 0 1 0 1 1 75937
> > Node 1, zone Normal, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0
> > Node 1, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
> >
> > After:
> > Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10
> > ...
> > Node 0, zone Normal, type Unmovable 152 158 37 2 2 0 3 4 2 6 717
> > Node 0, zone Normal, type Movable 1 37 53 3 55 49 16 6 2 1 75000
> > Node 0, zone Normal, type Reclaimable 1 4 3 1 2 1 1 1 1 1 0
> > Node 0, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
> > ...
> > Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10
> > Node 1, zone Normal, type Unmovable 5 3 2 1 3 4 2 2 2 0 779
> > Node 1, zone Normal, type Movable 1 0 1 1 1 0 1 0 1 1 75849
> > Node 1, zone Normal, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0
> > Node 1, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
>
> A good result. But the subject could be changed to:
>
> "mm/hugetlb: perform vmemmap optimization batchly for specific node allocation"
>
> >
> > Signed-off-by: suhua <suhua1@xxxxxxxxxxxx>
> > ---
> > mm/hugetlb.c | 37 +++++++++++++++++++++++++++++++++----
> > 1 file changed, 33 insertions(+), 4 deletions(-)
> >
> > diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> > index 190fa05635f4..3441d380c90b 100644
> > --- a/mm/hugetlb.c
> > +++ b/mm/hugetlb.c
> > @@ -2077,6 +2077,24 @@ static struct folio *only_alloc_fresh_hugetlb_folio(struct hstate *h,
> > return folio;
> > }
> >
> > +static struct folio *only_alloc_and_account_fresh_hugetlb_folio(
> > + struct hstate *h, gfp_t gfp_mask,
> > + int nid, nodemask_t *nmask)
> > +{
> > + struct folio *folio;
> > +
> > + folio = only_alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask, NULL);
> > + if (!folio)
> > + return NULL;
> > +
> > + spin_lock_irq(&hugetlb_lock);
> > + h->nr_huge_pages++;
> > + h->nr_huge_pages_node[nid]++;
> > + spin_unlock_irq(&hugetlb_lock);
> > +
> > + return folio;
> > +}
> > +
> > /*
> > * Common helper to allocate a fresh hugetlb page. All specific allocators
> > * should use this function to get new hugetlb pages
> > @@ -3301,23 +3319,34 @@ static void __init hugetlb_hstate_alloc_pages_onenode(struct hstate *h, int nid)
> > {
> > unsigned long i;
> > char buf[32];
> > + LIST_HEAD(folio_list);
> > + struct folio *folio, *tmp_f;
> >
> > for (i = 0; i < h->max_huge_pages_node[nid]; ++i) {
> > if (hstate_is_gigantic(h)) {
> > if (!alloc_bootmem_huge_page(h, nid))
> > break;
> > } else {
> > - struct folio *folio;
> > gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
> >
> > - folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid,
> > - &node_states[N_MEMORY]);
> > + folio = only_alloc_and_account_fresh_hugetlb_folio(h,
> > + gfp_mask, nid, &node_states[N_MEMORY]);
>
> I think we could use only_alloc_fresh_hugetlb_folio plus prep_and_add_allocated_folios
> to achieve the same goal but more simpler, right?
>
> > if (!folio)
> > break;
> > - free_huge_folio(folio); /* free it into the hugepage allocator */
> > + list_add(&folio->lru, &folio_list);
> > }
> > cond_resched();
> > }
> > +
> > + if (!list_empty(&folio_list)) {
> > + /* Send list for bulk vmemmap optimization processing */
> > + hugetlb_vmemmap_optimize_folios(h, &folio_list);
> > +
> > + list_for_each_entry_safe(folio, tmp_f, &folio_list, lru) {
> > + free_huge_folio(folio); /* free it into the hugepage allocator */
> > + }
> > + }
>
> We could use prep_and_add_allocated_folios here.
>
> Thanks.
>
> > +
> > if (i == h->max_huge_pages_node[nid])
> > return;
> >
> > --
> > 2.34.1
> >
>