On 22.11.24 15:44, Liam R. Howlett wrote:
* David Hildenbrand <david@xxxxxxxxxx> [241122 04:32]:
On 22.11.24 07:19, Andrew Morton wrote:
On Wed, 20 Nov 2024 15:27:46 -0500 "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> wrote:
I hate the extra check because syzbot can cause this as this should
basically never happen in real life, but it seems we have to add it.
So..
--- a/mm/mempolicy.c~mm-mempolicy-fix-migrate_to_node-assuming-there-is-at-least-one-vma-in-a-mm-fix
+++ a/mm/mempolicy.c
@@ -1080,7 +1080,7 @@ static long migrate_to_node(struct mm_st
mmap_read_lock(mm);
vma = find_vma(mm, 0);
- if (!vma) {
+ if (unlikely(!vma)) {
mmap_read_unlock(mm);
return 0;
}
_
?
Why not, at least for documentation purposes. Because I don't think this is
any fast-path we really care about, so expect the runtime effects to be
mostly negligible. Thanks!
The next email we get about this will be a bot with a micro benchmark
performance drop.
I'll be pleasantly surprised if our migration code is that fast such
that this here would matter :)
--
Cheers,
David / dhildenb
