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From:   Liam Howlett <liam.howlett@oracle.com>
To:     "maple-tree@lists.infradead.org" <maple-tree@lists.infradead.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "damon @ lists . linux . dev" <damon@lists.linux.dev>,
        SeongJae Park <sj@kernel.org>,
        David Hildenbrand <david@redhat.com>
Subject: [PATCH v10 46/69] acct: use VMA iterator instead of linked list
Thread-Topic: [PATCH v10 46/69] acct: use VMA iterator instead of linked list
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Date:   Tue, 21 Jun 2022 20:47:08 +0000
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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

The VMA iterator is faster than the linked list.

Link: https://lkml.kernel.org/r/20220504011345.662299-31-Liam.Howlett@oracl=
e.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 kernel/acct.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/kernel/acct.c b/kernel/acct.c
index 13706356ec54..62200d799b9b 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -555,15 +555,14 @@ void acct_collect(long exitcode, int group_dead)
 	unsigned long vsize =3D 0;
=20
 	if (group_dead && current->mm) {
+		struct mm_struct *mm =3D current->mm;
+		VMA_ITERATOR(vmi, mm, 0);
 		struct vm_area_struct *vma;
=20
-		mmap_read_lock(current->mm);
-		vma =3D current->mm->mmap;
-		while (vma) {
+		mmap_read_lock(mm);
+		for_each_vma(vmi, vma)
 			vsize +=3D vma->vm_end - vma->vm_start;
-			vma =3D vma->vm_next;
-		}
-		mmap_read_unlock(current->mm);
+		mmap_read_unlock(mm);
 	}
=20
 	spin_lock_irq(&current->sighand->siglock);
--=20
2.35.1