When handling the freed hugetlb or in-use hugetlb, we should ignore the
failure of alloc_buddy_hugetlb_folio() to dissolve the old hugetlb successfully,
since we did not use the new allocated hugetlb in this 2 cases. Moreover,
moving the allocation into the free hugetlb handling branch.
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
Changes from v1:
- Update the suject line per Muchun.
- Move the allocation into the free hugetlb handling branch per Michal.
---
mm/hugetlb.c | 40 ++++++++++++++++++++++++----------------
1 file changed, 24 insertions(+), 16 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 9d996fe4ecd9..4899167d3652 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3031,21 +3031,9 @@ static int alloc_and_dissolve_hugetlb_folio(struct hstate *h,
{
gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
int nid = folio_nid(old_folio);
- struct folio *new_folio;
+ struct folio *new_folio = NULL;
int ret = 0;
- /*
- * Before dissolving the folio, we need to allocate a new one for the
- * pool to remain stable. Here, we allocate the folio and 'prep' it
- * by doing everything but actually updating counters and adding to
- * the pool. This simplifies and let us do most of the processing
- * under the lock.
- */
- new_folio = alloc_buddy_hugetlb_folio(h, gfp_mask, nid, NULL, NULL);
- if (!new_folio)
- return -ENOMEM;
- __prep_new_hugetlb_folio(h, new_folio);
-
retry:
spin_lock_irq(&hugetlb_lock);
if (!folio_test_hugetlb(old_folio)) {
@@ -3075,6 +3063,24 @@ static int alloc_and_dissolve_hugetlb_folio(struct hstate *h,
cond_resched();
goto retry;
} else {
+ if (!new_folio) {
+ spin_unlock_irq(&hugetlb_lock);
+ /*
+ * Before dissolving the free hugetlb, we need to allocate
+ * a new one for the pool to remain stable. Here, we
+ * allocate the folio and 'prep' it by doing everything
+ * but actually updating counters and adding to the pool.
+ * This simplifies and let us do most of the processing
+ * under the lock.
+ */
+ new_folio = alloc_buddy_hugetlb_folio(h, gfp_mask, nid,
+ NULL, NULL);
+ if (!new_folio)
+ return -ENOMEM;
+ __prep_new_hugetlb_folio(h, new_folio);
+ goto retry;
+ }
+
/*
* Ok, old_folio is still a genuine free hugepage. Remove it from
* the freelist and decrease the counters. These will be
@@ -3102,9 +3108,11 @@ static int alloc_and_dissolve_hugetlb_folio(struct hstate *h,
free_new:
spin_unlock_irq(&hugetlb_lock);
- /* Folio has a zero ref count, but needs a ref to be freed */
- folio_ref_unfreeze(new_folio, 1);
- update_and_free_hugetlb_folio(h, new_folio, false);
+ if (new_folio) {
+ /* Folio has a zero ref count, but needs a ref to be freed */
+ folio_ref_unfreeze(new_folio, 1);
+ update_and_free_hugetlb_folio(h, new_folio, false);
+ }
return ret;
}
--
2.39.3
