Re: [PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls

From: Ira Weiny
Date: Wed Feb 10 2021 - 16:28:26 EST


On Wed, Feb 10, 2021 at 06:56:06PM +0000, Matthew Wilcox wrote:
> On Wed, Feb 10, 2021 at 08:29:01AM -0800, Ira Weiny wrote:
> > And I thought it was a good idea. Any file system development should have
> > tests with DEBUG_VM which should cover Matthew's concern while not having the
> > overhead in production. Seemed like a decent compromise?
>
> Why do you think these paths are only used during file system development?

I can't guarantee it but right now most of the conversions I have worked on are
in FS's.

> They're definitely used by networking, by device drivers of all kinds
> and they're probably even used by the graphics system.
>
> While developers *should* turn on DEBUG_VM during development, a
> shockingly high percentage don't even turn on lockdep.

Honestly, I don't feel strongly enough to argue it.

Andrew? David? David this is going through your tree so would you feel more
comfortable with 1 or the other?

Ira