From df8c841dd92a7f262ad4fa649aa493b181e02812 Mon Sep 17 00:00:00 2001 From: Bagas Sanjaya Date: Wed, 3 Dec 2025 08:09:11 +0700 Subject: [PATCH] NFSD: nfsd-io-modes: Separate lists Sphinx reports htmldocs indentation warnings: Documentation/filesystems/nfs/nfsd-io-modes.rst:58: ERROR: Unexpected indentation. [docutils] Documentation/filesystems/nfs/nfsd-io-modes.rst:59: WARNING: Block quote ends without a blank line; unexpected unindent. [docutils] These caused the lists to be shown as long running paragraphs merged with their previous paragraphs. Fix these by separating the lists with a blank line. Fixes: fa8d4e6784d1b6 ("NFSD: add Documentation/filesystems/nfs/nfsd-io-modes.rst") Reported-by: Stephen Rothwell Closes: https://lore.kernel.org/linux-next/20251202152506.7a2d2d41@canb.auug.org.au/ Signed-off-by: Bagas Sanjaya Reviewed-by: Jeff Layton Reviewed-by: Randy Dunlap Tested-by: Randy Dunlap Signed-off-by: Chuck Lever --- Documentation/filesystems/nfs/nfsd-io-modes.rst | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/Documentation/filesystems/nfs/nfsd-io-modes.rst b/Documentation/filesystems/nfs/nfsd-io-modes.rst index fa47c4d3dfb95..0fd6e82478fe6 100644 --- a/Documentation/filesystems/nfs/nfsd-io-modes.rst +++ b/Documentation/filesystems/nfs/nfsd-io-modes.rst @@ -13,6 +13,7 @@ to override that default to use either DONTCACHE or DIRECT IO modes. Experimental NFSD debugfs interfaces are available to allow the NFSD IO mode used for READ and WRITE to be configured independently. See both: + - /sys/kernel/debug/nfsd/io_cache_read - /sys/kernel/debug/nfsd/io_cache_write @@ -20,6 +21,7 @@ The default value for both io_cache_read and io_cache_write reflects NFSD's default IO mode (which is NFSD_IO_BUFFERED=0). Based on the configured settings, NFSD's IO will either be: + - cached using page cache (NFSD_IO_BUFFERED=0) - cached but removed from page cache on completion (NFSD_IO_DONTCACHE=1) - not cached stable_how=NFS_UNSTABLE (NFSD_IO_DIRECT=2) @@ -56,6 +58,7 @@ because the page cache will eventually become a bottleneck to servicing new IO requests. For more context on DONTCACHE, please see these Linux commit headers: + - Overview: 9ad6344568cc3 ("mm/filemap: change filemap_create_folio() to take a struct kiocb") - for READ: 8026e49bff9b1 ("mm/filemap: add read support for @@ -87,7 +90,9 @@ be made. The performance win associated with using NFSD DIRECT was previously discussed on linux-nfs, see: https://lore.kernel.org/linux-nfs/aEslwqa9iMeZjjlV@kernel.org/ + But in summary: + - NFSD DIRECT can significantly reduce memory requirements - NFSD DIRECT can reduce CPU load by avoiding costly page reclaim work - NFSD DIRECT can offer more deterministic IO performance -- 2.47.3