[PATCH v12 46/69] acct: use VMA iterator instead of linked list

Liam Howlett
2022-07-20T02:22:50Z

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@oracle.com
Link: https://lkml.kernel.org/r/20220621204632.3370049-47-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>
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 = 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);
--
2.35.1