Re: [PATCH v2 0/2] btrfs: teach send to avoid trashing the page cache with data

[David Sterba <dsterba@suse.cz>]

On Tue, May 17, 2022 at 11:47:28AM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> When doing a send operation, we read the data of all extents we need to
> send into the page cache, which almost always is wasteful as it can lead
> to eviction of other things from the page cache that are more useful for
> applications (and maybe other kernel subsystems). This patchset makes send
> evict the data from the page cache once it has sent it. The actual work
> is in the second patch, while the first one is just preparatory work.
> More details in the changelogs.
> 
> V2: Fixed it to work with subpage sector size. It was broken as we could
>     end up zeroing out part of a page when extents are not sector size
>     aligned. Reported by Qu.
> 
> Filipe Manana (2):
>   btrfs: send: keep the current inode open while processing it
>   btrfs: send: avoid trashing the page cache

Patch 1 is the same so I kept the committed version and 2 has been
replaced, still queued for first 5.19 pull as it's fixing a problem
that hampers testing. Thanks.