From: Josef Bacik <josef@toxicpanda.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Chris Mason <clm@fb.com>, David Sterba <dsterba@suse.com>,
Matthew Wilcox <willy@infradead.org>,
linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 16/23] btrfs: further simplify the compress or not logic in compress_file_range
Date: Fri, 14 Jul 2023 09:47:30 -0400 [thread overview]
Message-ID: <20230714134730.GC338010@perftesting> (raw)
In-Reply-To: <20230628153144.22834-17-hch@lst.de>
On Wed, Jun 28, 2023 at 05:31:37PM +0200, Christoph Hellwig wrote:
> Currently the logic whether to compress or not in compress_file_range is
> a bit convoluted because it tries to share code for creating inline
> extents for the compressible [1] path and the bail to uncompressed path.
>
> But the latter isn't needed at all, because cow_file_range as called by
> submit_uncompressed_range will already create inline extents as needed,
> so there is no need to have special handling for it if we can live with
> the fact that it will be called a bit later in the ->ordered_func of the
> workqueue instead of right now.
>
> [1] there is undocumented logic that creates an uncompressed inline
> extent outside of the shall not compress logic if total_in is too small.
> This logic isn't explained in comments or any commit log I could find,
> so I've preserved it. Documentation explaining it would be appreciated
> if anyone understands this code.
>
Looks like it's just a optimization, no reason to allocate a whole async extent
if we can just inline a page and be done. It's not necessarily required, but
could use a comment. Thanks,
Josef
next prev parent reply other threads:[~2023-07-14 13:47 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-28 15:31 btrfs compressed writeback cleanups Christoph Hellwig
2023-06-28 15:31 ` [PATCH 01/23] btrfs: pass a flags argument to cow_file_range Christoph Hellwig
2023-07-04 8:47 ` Johannes Thumshirn
2023-07-20 11:22 ` David Sterba
2023-07-20 13:25 ` Christoph Hellwig
2023-06-28 15:31 ` [PATCH 02/23] btrfs: don't create inline extents in fallback_to_cow Christoph Hellwig
2023-06-28 15:31 ` [PATCH 03/23] btrfs: split page locking out of __process_pages_contig Christoph Hellwig
2023-06-28 15:31 ` [PATCH 04/23] btrfs: remove btrfs_writepage_endio_finish_ordered Christoph Hellwig
2023-07-04 8:50 ` Johannes Thumshirn
2023-06-28 15:31 ` [PATCH 05/23] btrfs: remove end_extent_writepage Christoph Hellwig
2023-06-28 15:31 ` [PATCH 06/23] btrfs: reduce debug spam from submit_compressed_extents Christoph Hellwig
2023-07-04 8:54 ` Johannes Thumshirn
2023-06-28 15:31 ` [PATCH 07/23] btrfs: remove the return value from submit_uncompressed_range Christoph Hellwig
2023-07-04 8:56 ` Johannes Thumshirn
2023-06-28 15:31 ` [PATCH 08/23] btrfs: remove the return value from extent_write_locked_range Christoph Hellwig
2023-07-04 8:56 ` Johannes Thumshirn
2023-06-28 15:31 ` [PATCH 09/23] btrfs: improve the delalloc_to_write calculation in writepage_delalloc Christoph Hellwig
2023-06-28 15:31 ` [PATCH 10/23] btrfs: reduce the number of arguments to btrfs_run_delalloc_range Christoph Hellwig
2023-07-04 9:00 ` Johannes Thumshirn
2023-06-28 15:31 ` [PATCH 11/23] btrfs: clean up the check for uncompressed ranges in submit_one_async_extent Christoph Hellwig
2023-07-04 9:07 ` Johannes Thumshirn
2023-06-28 15:31 ` [PATCH 12/23] btrfs: don't clear async_chunk->inode in async_cow_start Christoph Hellwig
2023-06-28 15:31 ` [PATCH 13/23] btrfs: merge async_cow_start and compress_file_range Christoph Hellwig
2023-07-04 9:09 ` Johannes Thumshirn
2023-06-28 15:31 ` [PATCH 14/23] btrfs: merge submit_compressed_extents and async_cow_submit Christoph Hellwig
2023-06-28 15:31 ` [PATCH 15/23] btrfs: streamline compress_file_range Christoph Hellwig
2023-06-28 15:31 ` [PATCH 16/23] btrfs: further simplify the compress or not logic in compress_file_range Christoph Hellwig
2023-07-14 13:47 ` Josef Bacik [this message]
2023-06-28 15:31 ` [PATCH 17/23] btrfs: use a separate label for the incompressible case " Christoph Hellwig
2023-06-28 15:31 ` [PATCH 18/23] btrfs: share the code to free the page array " Christoph Hellwig
2023-06-28 15:31 ` [PATCH 19/23] btrfs: don't redirty pages " Christoph Hellwig
2023-07-20 11:41 ` David Sterba
2023-07-20 13:26 ` Christoph Hellwig
2023-06-28 15:31 ` [PATCH 20/23] btrfs: refactor the zoned device handling in cow_file_range Christoph Hellwig
2023-06-28 15:31 ` [PATCH 21/23] btrfs: don't redirty locked_page in run_delalloc_zoned Christoph Hellwig
2023-06-28 15:31 ` [PATCH 22/23] btrfs: fix zoned handling in submit_uncompressed_range Christoph Hellwig
2023-06-28 15:31 ` [PATCH 23/23] mm: remove folio_account_redirty Christoph Hellwig
2023-06-28 15:45 ` Matthew Wilcox
2023-07-14 13:49 ` btrfs compressed writeback cleanups Josef Bacik
2023-07-20 11:47 ` David Sterba
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