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

[PATCH V2 0/8] btrfs: convert kmaps to core page calls · <hidden> · 2021-02-10
[PATCH V2 1/8] mm/highmem: Lift memcpy_[to|from]_page to core · <hidden> · 2021-02-10
Re: [PATCH V2 1/8] mm/highmem: Lift memcpy_[to|from]_page to core · Chaitanya Kulkarni <hidden> · 2021-02-10
Re: [PATCH V2 1/8] mm/highmem: Lift memcpy_[to|from]_page to core · Christoph Hellwig <hch@infradead.org> · 2021-02-10
[PATCH V2 2/8] mm/highmem: Convert memcpy_[to|from]_page() to kmap_local_page() · <hidden> · 2021-02-10
Re: [PATCH V2 2/8] mm/highmem: Convert memcpy_[to|from]_page() to kmap_local_page() · Chaitanya Kulkarni <hidden> · 2021-02-10
Re: [PATCH V2 2/8] mm/highmem: Convert memcpy_[to|from]_page() to kmap_local_page() · Christoph Hellwig <hch@infradead.org> · 2021-02-10
[PATCH V2 3/8] mm/highmem: Introduce memcpy_page(), memmove_page(), and memset_page() · <hidden> · 2021-02-10
Re: [PATCH V2 3/8] mm/highmem: Introduce memcpy_page(), memmove_page(), and memset_page() · Chaitanya Kulkarni <hidden> · 2021-02-10
Re: [PATCH V2 3/8] mm/highmem: Introduce memcpy_page(), memmove_page(), and memset_page() · Christoph Hellwig <hch@infradead.org> · 2021-02-10
[PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls · <hidden> · 2021-02-10
Re: [PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls · Chaitanya Kulkarni <hidden> · 2021-02-10
Re: [PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls · Ira Weiny <hidden> · 2021-02-10
Re: [PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls · Christoph Hellwig <hch@infradead.org> · 2021-02-10
Re: [PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls · Ira Weiny <hidden> · 2021-02-10
Re: [PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls · Christoph Hellwig <hch@infradead.org> · 2021-02-10
Re: [PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls · Ira Weiny <hidden> · 2021-02-10
Re: [PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls · Matthew Wilcox <willy@infradead.org> · 2021-02-10
Re: [PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls · Ira Weiny <hidden> · 2021-02-10
Re: [PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls · David Sterba <hidden> · 2021-02-11
[PATCH V2.1] mm/highmem: Add VM_BUG_ON() to mem*_page() calls · <hidden> · 2021-02-10
[PATCH V2 5/8] iov_iter: Remove memzero_page() in favor of zero_user() · <hidden> · 2021-02-10
Re: [PATCH V2 5/8] iov_iter: Remove memzero_page() in favor of zero_user() · Christoph Hellwig <hch@infradead.org> · 2021-02-10
[PATCH V2 6/8] btrfs: use memcpy_[to|from]_page() and kmap_local_page() · <hidden> · 2021-02-10
Re: [PATCH V2 6/8] btrfs: use memcpy_[to|from]_page() and kmap_local_page() · Christoph Hellwig <hch@infradead.org> · 2021-02-10
[PATCH V2 7/8] btrfs: use copy_highpage() instead of 2 kmaps() · <hidden> · 2021-02-10
Re: [PATCH V2 7/8] btrfs: use copy_highpage() instead of 2 kmaps() · Christoph Hellwig <hch@infradead.org> · 2021-02-10
[PATCH V2 8/8] btrfs: convert to zero_user() · <hidden> · 2021-02-10
Re: [PATCH V2 8/8] btrfs: convert to zero_user() · Christoph Hellwig <hch@infradead.org> · 2021-02-10
Re: [PATCH V2 0/8] btrfs: convert kmaps to core page calls · David Sterba <hidden> · 2021-02-11
Re: [PATCH V2 0/8] btrfs: convert kmaps to core page calls · Ira Weiny <hidden> · 2021-02-11

From: Matthew Wilcox <willy@infradead.org>
Date: 2021-02-10 18:59:11
Also in: lkml

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?
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.

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