From: Matthew Wilcox (Oracle) <willy@infradead.org>
Date: Wed, 20 Jul 2022 02:17:58 +0000 (+0000)
Subject: acct: use VMA iterator instead of linked list
X-Git-Tag: howlett/maple/20220816~23
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=04f4eb8218480e7b49ad52825cbd4457d2e5ba92;p=users%2Fjedix%2Flinux-maple.git

acct: use VMA iterator instead of linked list

The VMA iterator is faster than the linked list.

Link: https://lkml.kernel.org/r/20220504011345.662299-31-Liam.Howlett@oracle.com
Link: https://lkml.kernel.org/r/20220621204632.3370049-47-Liam.Howlett@oracle.com
Link: https://lkml.kernel.org/r/20220720021727.17018-47-Liam.Howlett@oracle.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>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hulk Robot <hulkci@huawei.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

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 = 0;
 
 	if (group_dead && current->mm) {
+		struct mm_struct *mm = current->mm;
+		VMA_ITERATOR(vmi, mm, 0);
 		struct vm_area_struct *vma;
 
-		mmap_read_lock(current->mm);
-		vma = current->mm->mmap;
-		while (vma) {
+		mmap_read_lock(mm);
+		for_each_vma(vmi, vma)
 			vsize += vma->vm_end - vma->vm_start;
-			vma = vma->vm_next;
-		}
-		mmap_read_unlock(current->mm);
+		mmap_read_unlock(mm);
 	}
 
 	spin_lock_irq(&current->sighand->siglock);