[PATCH] mm: Track mmu notifiers in fs_reclaim_acquire/release

[Qian Cai]

> On Jun 23, 2020, at 6:13 PM, Daniel Vetter <daniel at ffwll.ch> wrote:
> 
> Ok I tested this. I can't use your script to repro because
> - I don't have a setup with xfs, and the splat points at an issue in xfs
> - reproducing lockdep splats in shrinker callbacks is always a bit tricky

What’s xfs setup are you talking about? This is simple xfs rootfs and then trigger swapping. Nothing tricky here as it hit on multiple machines within a few seconds on linux-next.

> Summary: Everything is working as expected, there's no change in the
> lockdep annotations.
> I really think the problem is that either your testcase doesn't hit
> the issue reliably enough, or that you're not actually testing the
> same kernels and there's some other changes (xfs most likely, but
> really it could be anywhere) which is causing this regression. I'm
> rather convinced now after this test that it's not my stuff.

Well, the memory pressure workloads have been running for years on daily linux-next builds and never saw this one happened once. Also, the reverting is ONLY to revert your patch on the top of linux-next will stop the splat, so there is no not testing the same kernel at all.