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 13706356ec54d4386eb37d563e3a13d769da63e0..62200d799b9b0066a770ffe308a5eae2250edfd7 100644 (file)
--- 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);