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Date:   Wed, 10 Feb 2021 13:22:28 -0800
From:   Ira Weiny <ira.weiny@intel.com>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        David Sterba <dsterba@suse.cz>, clm@fb.com,
        josef@toxicpanda.com, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls
Message-ID: <20210210212228.GF3014244@iweiny-DESK2.sc.intel.com>
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 <20210210162901.GB3014244@iweiny-DESK2.sc.intel.com>
 <20210210185606.GF308988@casper.infradead.org>
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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