From 72d8f72631d278c7003defbe3fe88fe5332822f8 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Tue, 7 Jan 2025 15:40:01 -0500 Subject: [PATCH] mm/hugetlb: drop vma_has_reserves() After the previous cleanup, vma_has_reserves() is mostly an empty helper except that it says "use reserve count" is inverted meaning from "needs a global reserve count", which is still true. To avoid confusions on having two inverted ways to ask the same question, always use the gbl_chg everywhere, and drop the function. When at it, rename "chg" to "gbl_chg" in dequeue_hugetlb_folio_vma(). It might be helpful for readers to see that the "chg" here is the global reserve count, not the vma resv count. Link: https://lkml.kernel.org/r/20250107204002.2683356-7-peterx@redhat.com Signed-off-by: Peter Xu Cc: Ackerley Tng Cc: Breno Leitao Cc: Muchun Song Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Rik van Riel Cc: Roman Gushchin Signed-off-by: Andrew Morton --- mm/hugetlb.c | 23 ++++++----------------- 1 file changed, 6 insertions(+), 17 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index efd8e9f9bf0e..8e46798a9dfc 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1247,16 +1247,6 @@ void clear_vma_resv_huge_pages(struct vm_area_struct *vma) hugetlb_dup_vma_private(vma); } -/* Returns true if the VMA has associated reserve pages */ -static bool vma_has_reserves(long chg) -{ - /* - * Now "chg" has all the conditions considered for whether we - * should use an existing reservation. - */ - return chg == 0; -} - static void enqueue_hugetlb_folio(struct hstate *h, struct folio *folio) { int nid = folio_nid(folio); @@ -1345,7 +1335,7 @@ static unsigned long available_huge_pages(struct hstate *h) static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h, struct vm_area_struct *vma, - unsigned long address, long chg) + unsigned long address, long gbl_chg) { struct folio *folio = NULL; struct mempolicy *mpol; @@ -1354,11 +1344,10 @@ static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h, int nid; /* - * A child process with MAP_PRIVATE mappings created by their parent - * have no page reserves. This check ensures that reservations are - * not "stolen". The child may still get SIGKILLed + * gbl_chg==1 means the allocation requires a new page that was not + * reserved before. Making sure there's at least one free page. */ - if (!vma_has_reserves(chg) && !available_huge_pages(h)) + if (gbl_chg && !available_huge_pages(h)) goto err; gfp_mask = htlb_alloc_mask(h); @@ -1376,7 +1365,7 @@ static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h, folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask, nid, nodemask); - if (folio && vma_has_reserves(chg)) { + if (folio && !gbl_chg) { folio_set_hugetlb_restore_reserve(folio); h->resv_huge_pages--; } @@ -3067,7 +3056,7 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma, if (!folio) goto out_uncharge_cgroup; spin_lock_irq(&hugetlb_lock); - if (vma_has_reserves(gbl_chg)) { + if (!gbl_chg) { folio_set_hugetlb_restore_reserve(folio); h->resv_huge_pages--; } -- 2.25.1