linux-kernel - [PATCH v2 3/5] mm,hugetlb: Rename anon_rmap to new_anon

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Message-ID: <20250620123014.29748-4-osalvador@suse.de>
Date: Fri, 20 Jun 2025 14:30:12 +0200
From: Oscar Salvador <osalvador@...e.de>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: David Hildenbrand <david@...hat.com>,
	Muchun Song <muchun.song@...ux.dev>,
	Peter Xu <peterx@...hat.com>,
	Gavin Guo <gavinguo@...lia.com>,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	Oscar Salvador <osalvador@...e.de>
Subject: [PATCH v2 3/5] mm,hugetlb: Rename anon_rmap to new_anon_folio and make it boolean

anon_rmap is used to determine whether the new allocated folio is anonymous.
Rename it to something more meaningul like new_anon_folio and make it boolean,
as we use it like that.
While we are at it, drop 'new_pagecache_folio' as 'new_anon_folio' is enough to
check whether we need to restore the consumed reservation.

Signed-off-by: Oscar Salvador <osalvador@...e.de>
---
 mm/hugetlb.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 1a5f713c1e4c..57bb8b2dce21 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6427,17 +6427,16 @@ static bool hugetlb_pte_stable(struct hstate *h, struct mm_struct *mm, unsigned
 static vm_fault_t hugetlb_no_page(struct address_space *mapping,
 			struct vm_fault *vmf)
 {
+	u32 hash = hugetlb_fault_mutex_hash(mapping, vmf->pgoff);
+	bool new_folio, new_anon_folio = false;
 	struct vm_area_struct *vma = vmf->vma;
 	struct mm_struct *mm = vma->vm_mm;
 	struct hstate *h = hstate_vma(vma);
 	vm_fault_t ret = VM_FAULT_SIGBUS;
-	int anon_rmap = 0;
-	unsigned long size;
+	bool folio_locked = true;
 	struct folio *folio;
+	unsigned long size;
 	pte_t new_pte;
-	bool new_folio, new_pagecache_folio = false;
-	u32 hash = hugetlb_fault_mutex_hash(mapping, vmf->pgoff);
-	bool folio_locked = true;
 
 	/*
 	 * Currently, we are forced to kill the process in the event the
@@ -6518,6 +6517,7 @@ static vm_fault_t hugetlb_no_page(struct address_space *mapping,
 		folio_zero_user(folio, vmf->real_address);
 		__folio_mark_uptodate(folio);
 		new_folio = true;
+		new_anon_folio = !(vma->vm_flags & VM_MAYSHARE);
 
 		if (vma->vm_flags & VM_MAYSHARE) {
 			int err = hugetlb_add_to_page_cache(folio, mapping,
@@ -6536,10 +6536,8 @@ static vm_fault_t hugetlb_no_page(struct address_space *mapping,
 				ret = VM_FAULT_SIGBUS;
 				goto out;
 			}
-			new_pagecache_folio = true;
 		} else {
 			folio_lock(folio);
-			anon_rmap = 1;
 		}
 	} else {
 		/*
@@ -6588,7 +6586,7 @@ static vm_fault_t hugetlb_no_page(struct address_space *mapping,
 	if (!pte_same(huge_ptep_get(mm, vmf->address, vmf->pte), vmf->orig_pte))
 		goto backout;
 
-	if (anon_rmap)
+	if (new_anon_folio)
 		hugetlb_add_new_anon_rmap(folio, vma, vmf->address);
 	else
 		hugetlb_add_file_rmap(folio);
@@ -6604,7 +6602,7 @@ static vm_fault_t hugetlb_no_page(struct address_space *mapping,
 	hugetlb_count_add(pages_per_huge_page(h), mm);
 	if ((vmf->flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
 		/* No need to lock file folios. See comment in hugetlb_fault() */
-		if (!anon_rmap) {
+		if (!new_anon_folio) {
 			folio_locked = false;
 			folio_unlock(folio);
 		}
@@ -6640,7 +6638,8 @@ static vm_fault_t hugetlb_no_page(struct address_space *mapping,
 backout:
 	spin_unlock(vmf->ptl);
 backout_unlocked:
-	if (new_folio && !new_pagecache_folio)
+	/* We only need to restore reservations for private mappings */
+	if (new_folio && new_anon_folio)
 		restore_reserve_on_error(h, vma, vmf->address, folio);
 
 	if (folio_locked)
-- 
2.50.0