[RFC PATCH 0/2] Implement concurrent buffered write with folio lock

[Chi Zhiling <chizhiling@163.com>]

From: Chi Zhiling <chizhiling@kylinos.cn>

This is a patch attempting to implement concurrent buffered writes.
The main idea is to use the folio lock to ensure the atomicity of the
write when writing to a single folio, instead of using the i_rwsem.

I tried the "folio batch" solution, which is a great idea, but during
testing, I encountered an OOM issue because the locked folios couldn't
be reclaimed.

So for now, I can only allow concurrent writes within a single block.
The good news is that since we already support BS > PS, we can use a
larger block size to enable higher granularity concurrency.

These ideas come from previous discussions:
https://lore.kernel.org/all/953b0499-5832-49dc-8580-436cf625db8c@163.com/


Chi Zhiling (2):
  xfs: Add i_direct_mode to indicate the IO mode of inode
  xfs: Enable concurrency when writing within single block

 fs/xfs/xfs_file.c  | 71 ++++++++++++++++++++++++++++++++++++++++++----
 fs/xfs/xfs_inode.h |  6 ++++
 2 files changed, 72 insertions(+), 5 deletions(-)

-- 
2.43.0