linux-kernel - [RFC PATCH 3/3] mm, hugetlb: Drop unlikelys from hugetlb

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Message-ID: <20250602141610.173698-4-osalvador@suse.de>
Date: Mon,  2 Jun 2025 16:16:10 +0200
From: Oscar Salvador <osalvador@...e.de>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Muchun Song <muchun.song@...ux.dev>,
	David Hildenbrand <david@...hat.com>,
	James Houghton <jthoughton@...gle.com>,
	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: [RFC PATCH 3/3] mm, hugetlb: Drop unlikelys from hugetlb_fault

The unlikely predates an era where we were checking for
hwpoisoned/migration entries without knowing whether the pte was
present.

The code-flow has changed, and we do not do that anymore, plus
they do not bring any advantatge at all.

Signed-off-by: Oscar Salvador <osalvador@...e.de>
---
 mm/hugetlb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 6ef90958839f..02ede63e7e5e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6768,7 +6768,7 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 	 * or hwpoisoned entry.
 	 */
 	if (!pte_present(vmf.orig_pte)) {
-		if (unlikely(is_hugetlb_entry_migration(vmf.orig_pte))) {
+		if (is_hugetlb_entry_migration(vmf.orig_pte)) {
 			/*
 			 * Release the hugetlb fault lock now, but retain
 			 * the vma lock, because it is needed to guard the
@@ -6779,7 +6779,7 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 			migration_entry_wait_huge(vma, vmf.address, vmf.pte);
 			return 0;
-		} else if (unlikely(is_hugetlb_entry_hwpoisoned(vmf.orig_pte)))
+		} else if (is_hugetlb_entry_hwpoisoned(vmf.orig_pte))
 			ret = VM_FAULT_HWPOISON_LARGE |
 			    VM_FAULT_SET_HINDEX(hstate_index(h));
 		goto out_mutex;
-- 
2.49.0