From: Christoph Hellwig <hch@infradead.org>
To: Chuck Lever <cel@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>,
NeilBrown <neil@brown.name>, Jeff Layton <jlayton@kernel.org>,
Olga Kornievskaia <okorniev@redhat.com>,
Dai Ngo <dai.ngo@oracle.com>, Tom Talpey <tom@talpey.com>,
linux-nfs@vger.kernel.org, Mike Snitzer <snitzer@kernel.org>,
Chuck Lever <chuck.lever@oracle.com>
Subject: Re: [PATCH v11 2/3] NFSD: Implement NFSD_IO_DIRECT for NFS WRITE
Date: Mon, 10 Nov 2025 01:17:19 -0800 [thread overview]
Message-ID: <aRGtn90M8ktOCOnv@infradead.org> (raw)
In-Reply-To: <4714c5d0-cc40-4442-a8af-7f29cbb1b35d@kernel.org>
On Fri, Nov 07, 2025 at 03:28:06PM -0500, Chuck Lever wrote:
> +1 for an explanatory comment, but I'm not getting what is "counter-
> intuitive" about leaving the content of the end segments in the page
> cache. The end segments are small and simply cannot be handled by direct
> I/O.
The downside if of course extra page cache usage / pollution. If these
segments are aligned to the file system minimum I/O size, but not to
the memory requirements there is not going to be any RMW cycle that
leaving them in the page cache for would be useful.
Similarly if the single segment is not aligned in the file logic space,
chances of having another RMW come in are the same as for a large
one with unaligned head and/or tail.
next prev parent reply other threads:[~2025-11-10 9:17 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-07 15:34 [PATCH v11 0/3] NFSD: Implement NFSD_IO_DIRECT for NFS WRITE Chuck Lever
2025-11-07 15:34 ` [PATCH v11 1/3] NFSD: Make FILE_SYNC WRITEs comply with spec Chuck Lever
2025-11-07 15:34 ` [PATCH v11 2/3] NFSD: Implement NFSD_IO_DIRECT for NFS WRITE Chuck Lever
2025-11-07 15:39 ` Christoph Hellwig
2025-11-07 15:40 ` Chuck Lever
2025-11-07 20:05 ` Mike Snitzer
2025-11-07 20:08 ` Chuck Lever
2025-11-07 20:10 ` Mike Snitzer
2025-11-07 21:58 ` NeilBrown
2025-11-07 22:24 ` Mike Snitzer
2025-11-07 23:42 ` NeilBrown
2025-11-08 2:01 ` Mike Snitzer
2025-11-10 16:41 ` Chuck Lever
2025-11-10 17:57 ` Mike Snitzer
2025-11-11 8:51 ` Christoph Hellwig
2025-11-11 14:20 ` Chuck Lever
2025-11-11 14:21 ` Christoph Hellwig
2025-11-12 0:06 ` Mike Snitzer
2025-11-12 15:02 ` Christoph Hellwig
2025-11-12 23:14 ` Mike Snitzer
2025-11-13 8:13 ` Christoph Hellwig
2025-11-13 21:45 ` Mike Snitzer
2025-11-07 20:28 ` Chuck Lever
2025-11-07 22:16 ` Mike Snitzer
2025-11-10 9:12 ` Christoph Hellwig
2025-11-10 15:42 ` Mike Snitzer
2025-11-11 8:44 ` Christoph Hellwig
2025-11-10 9:17 ` Christoph Hellwig [this message]
2025-11-10 15:43 ` Mike Snitzer
2025-11-07 17:18 ` Mike Snitzer
2025-11-07 22:13 ` NeilBrown
2025-11-07 15:34 ` [PATCH v11 3/3] NFSD: add Documentation/filesystems/nfs/nfsd-io-modes.rst Chuck Lever
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