[RFC PATCH 06/39] mm: hugetlb: Refactor dequeue_hugetlb_folio_vma() to use mpol

Ackerley Tng
2024-09-10T23:44:43Z

Reduce dependence on vma since the use of huge_node() assumes
that the mempolicy is stored in a specific place in the inode,
accessed via the vma.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
mm/hugetlb.c | 55 ++++++++++++++++++++++------------------------------
1 file changed, 23 insertions(+), 32 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 2f2bd2444ae2..e341bc0eb49a 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1402,44 +1402,33 @@ static unsigned long available_huge_pages(struct hstate *h)
return h->free_huge_pages - h->resv_huge_pages;
}

-static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h,
- struct vm_area_struct *vma,
- unsigned long address, bool use_hstate_resv)
+static struct folio *dequeue_hugetlb_folio(struct hstate *h,
+ struct mempolicy *mpol, int nid,
+ nodemask_t *nodemask,
+ bool use_hstate_resv)
{
struct folio *folio = NULL;
- struct mempolicy *mpol;
gfp_t gfp_mask;
- nodemask_t *nodemask;
- int nid;

if (!use_hstate_resv && !available_huge_pages(h))
- goto err;
+ return NULL;

gfp_mask = htlb_alloc_mask(h);
- nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);

- if (mpol_is_preferred_many(mpol)) {
- folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask,
- nid, nodemask);
+ if (mpol_is_preferred_many(mpol))
+ folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask, nid, nodemask);

- /* Fallback to all nodes if page==NULL */
- nodemask = NULL;
+ if (!folio) {
+ /* Fallback to all nodes if earlier allocation failed */
+ folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask, nid, NULL);
}

- if (!folio)
- folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask,
- nid, nodemask);
-
if (folio && use_hstate_resv) {
folio_set_hugetlb_restore_reserve(folio);
h->resv_huge_pages--;
}

- mpol_cond_put(mpol);
return folio;
-
-err:
- return NULL;
}

/*
@@ -3131,6 +3120,10 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
bool deferred_reserve;
gfp_t gfp = htlb_alloc_mask(h) | __GFP_RETRY_MAYFAIL;
bool use_hstate_resv;
+ struct mempolicy *mpol;
+ nodemask_t *nodemask;
+ pgoff_t ilx;
+ int nid;

memcg = get_mem_cgroup_from_current();
memcg_charge_ret = mem_cgroup_hugetlb_try_charge(memcg, gfp, nr_pages);
@@ -3184,22 +3177,19 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
use_hstate_resv = should_use_hstate_resv(vma, gbl_chg, avoid_reserve);

spin_lock_irq(&hugetlb_lock);
- folio = dequeue_hugetlb_folio_vma(h, vma, addr, use_hstate_resv);
- if (!folio) {
- struct mempolicy *mpol;
- nodemask_t *nodemask;
- pgoff_t ilx;
- int nid;

+ mpol = get_vma_policy(vma, addr, hstate_vma(vma)->order, &ilx);
+ nid = policy_node_nodemask(mpol, htlb_alloc_mask(h), ilx, &nodemask);
+ folio = dequeue_hugetlb_folio(h, mpol, nid, nodemask, use_hstate_resv);
+ if (!folio) {
spin_unlock_irq(&hugetlb_lock);

- mpol = get_vma_policy(vma, addr, hstate_vma(vma)->order, &ilx);
- nid = policy_node_nodemask(mpol, htlb_alloc_mask(h), ilx, &nodemask);
folio = alloc_buddy_hugetlb_folio_from_node(h, mpol, nid, nodemask);
- mpol_cond_put(mpol);
-
- if (!folio)
+ if (!folio) {
+ mpol_cond_put(mpol);
goto out_uncharge_cgroup;
+ }
+
spin_lock_irq(&hugetlb_lock);
if (use_hstate_resv) {
folio_set_hugetlb_restore_reserve(folio);
@@ -3209,6 +3199,7 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
folio_ref_unfreeze(folio, 1);
/* Fall through */
}
+ mpol_cond_put(mpol);

hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, folio);
/* If allocation is not consuming a reservation, also store the
--
2.46.0.598.g6f2099f65c-goog