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linux/fs/nfsd/debugfs.c

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NFSD: Add /sys/kernel/debug/nfsd Create a small sandbox under /sys/kernel/debug for experimental NFS server feature settings. There is no API/ABI compatibility guarantee for these settings. The only documentation for such settings, if any documentation exists, is in the kernel source code. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-03-08 15:14:37 -05:00
NFSD: Add experimental setting to disable the use of splice read NFSD currently has two separate code paths for handling read requests. One uses page splicing; the other is a traditional read based on an iov iterator. Because most Linux file systems support splice read, the latter does not get nearly the same test experience as splice reads. To force the use of vectored reads for testing and benchmarking, introduce the ability to disable splice reads for all NFS READ operations. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-03-08 15:14:38 -05:00
NFSD: Drop redundant conversion to bool The result of integer comparison already evaluates to bool. No need for explicit conversion. Signed-off-by: Xichao Zhao <zhao.xichao@vivo.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-08-18 18:03:20 +08:00
NFSD: Add io_cache_{read,write} controls to debugfs Add 'io_cache_read' to NFSD's debugfs interface so that any data read by NFSD will either be: - cached using page cache (NFSD_IO_BUFFERED=0) - cached but removed from the page cache upon completion (NFSD_IO_DONTCACHE=1). io_cache_read may be set by writing to: /sys/kernel/debug/nfsd/io_cache_read Add 'io_cache_write' to NFSD's debugfs interface so that any data written by NFSD will either be: - cached using page cache (NFSD_IO_BUFFERED=0) - cached but removed from the page cache upon completion (NFSD_IO_DONTCACHE=1). io_cache_write may be set by writing to: /sys/kernel/debug/nfsd/io_cache_write The default value for both settings is NFSD_IO_BUFFERED, which is NFSD's existing behavior for both read and write. Changes to these settings take immediate effect for all exports and NFS versions. Currently only xfs and ext4 implement RWF_DONTCACHE. For file systems that do not implement RWF_DONTCACHE, NFSD use only buffered I/O when the io_cache setting is NFSD_IO_DONTCACHE. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-09-06 17:25:11 -04:00
NFSD: Add experimental setting to disable the use of splice read NFSD currently has two separate code paths for handling read requests. One uses page splicing; the other is a traditional read based on an iov iterator. Because most Linux file systems support splice read, the latter does not get nearly the same test experience as splice reads. To force the use of vectored reads for testing and benchmarking, introduce the ability to disable splice reads for all NFS READ operations. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-03-08 15:14:38 -05:00
NFSD: Add io_cache_{read,write} controls to debugfs Add 'io_cache_read' to NFSD's debugfs interface so that any data read by NFSD will either be: - cached using page cache (NFSD_IO_BUFFERED=0) - cached but removed from the page cache upon completion (NFSD_IO_DONTCACHE=1). io_cache_read may be set by writing to: /sys/kernel/debug/nfsd/io_cache_read Add 'io_cache_write' to NFSD's debugfs interface so that any data written by NFSD will either be: - cached using page cache (NFSD_IO_BUFFERED=0) - cached but removed from the page cache upon completion (NFSD_IO_DONTCACHE=1). io_cache_write may be set by writing to: /sys/kernel/debug/nfsd/io_cache_write The default value for both settings is NFSD_IO_BUFFERED, which is NFSD's existing behavior for both read and write. Changes to these settings take immediate effect for all exports and NFS versions. Currently only xfs and ext4 implement RWF_DONTCACHE. For file systems that do not implement RWF_DONTCACHE, NFSD use only buffered I/O when the io_cache setting is NFSD_IO_DONTCACHE. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-09-06 17:25:11 -04:00
NFSD: Implement NFSD_IO_DIRECT for NFS READ Add an experimental option that forces NFS READ operations to use direct I/O instead of reading through the NFS server's page cache. There is already at least one other layer of read caching: the page cache on NFS clients. The server's page cache, in many cases, is unlikely to provide additional benefit. Some benchmarks have demonstrated that the server's page cache is actively detrimental for workloads whose working set is larger than the server's available physical memory. For instance, on small NFS servers, cached NFS file content can squeeze out local memory consumers. For large sequential workloads, an enormous amount of data flows into and out of the page cache and is consumed by NFS clients exactly once -- caching that data is expensive to do and totally valueless. For now this is a hidden option that can be enabled on test systems for benchmarking. In the longer term, this option might be enabled persistently or per-export. When the exported file system does not support direct I/O, NFSD falls back to using either DONTCACHE or buffered I/O to fulfill NFS READ requests. Suggested-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: NeilBrown <neil@brown.name> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-10-08 09:52:30 -04:00
NFSD: Add io_cache_{read,write} controls to debugfs Add 'io_cache_read' to NFSD's debugfs interface so that any data read by NFSD will either be: - cached using page cache (NFSD_IO_BUFFERED=0) - cached but removed from the page cache upon completion (NFSD_IO_DONTCACHE=1). io_cache_read may be set by writing to: /sys/kernel/debug/nfsd/io_cache_read Add 'io_cache_write' to NFSD's debugfs interface so that any data written by NFSD will either be: - cached using page cache (NFSD_IO_BUFFERED=0) - cached but removed from the page cache upon completion (NFSD_IO_DONTCACHE=1). io_cache_write may be set by writing to: /sys/kernel/debug/nfsd/io_cache_write The default value for both settings is NFSD_IO_BUFFERED, which is NFSD's existing behavior for both read and write. Changes to these settings take immediate effect for all exports and NFS versions. Currently only xfs and ext4 implement RWF_DONTCACHE. For file systems that do not implement RWF_DONTCACHE, NFSD use only buffered I/O when the io_cache setting is NFSD_IO_DONTCACHE. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-09-06 17:25:11 -04:00
NFSD: Implement NFSD_IO_DIRECT for NFS READ Add an experimental option that forces NFS READ operations to use direct I/O instead of reading through the NFS server's page cache. There is already at least one other layer of read caching: the page cache on NFS clients. The server's page cache, in many cases, is unlikely to provide additional benefit. Some benchmarks have demonstrated that the server's page cache is actively detrimental for workloads whose working set is larger than the server's available physical memory. For instance, on small NFS servers, cached NFS file content can squeeze out local memory consumers. For large sequential workloads, an enormous amount of data flows into and out of the page cache and is consumed by NFS clients exactly once -- caching that data is expensive to do and totally valueless. For now this is a hidden option that can be enabled on test systems for benchmarking. In the longer term, this option might be enabled persistently or per-export. When the exported file system does not support direct I/O, NFSD falls back to using either DONTCACHE or buffered I/O to fulfill NFS READ requests. Suggested-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: NeilBrown <neil@brown.name> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-10-08 09:52:30 -04:00
NFSD: Add io_cache_{read,write} controls to debugfs Add 'io_cache_read' to NFSD's debugfs interface so that any data read by NFSD will either be: - cached using page cache (NFSD_IO_BUFFERED=0) - cached but removed from the page cache upon completion (NFSD_IO_DONTCACHE=1). io_cache_read may be set by writing to: /sys/kernel/debug/nfsd/io_cache_read Add 'io_cache_write' to NFSD's debugfs interface so that any data written by NFSD will either be: - cached using page cache (NFSD_IO_BUFFERED=0) - cached but removed from the page cache upon completion (NFSD_IO_DONTCACHE=1). io_cache_write may be set by writing to: /sys/kernel/debug/nfsd/io_cache_write The default value for both settings is NFSD_IO_BUFFERED, which is NFSD's existing behavior for both read and write. Changes to these settings take immediate effect for all exports and NFS versions. Currently only xfs and ext4 implement RWF_DONTCACHE. For file systems that do not implement RWF_DONTCACHE, NFSD use only buffered I/O when the io_cache setting is NFSD_IO_DONTCACHE. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-09-06 17:25:11 -04:00
NFSD: Implement NFSD_IO_DIRECT for NFS WRITE When NFSD_IO_DIRECT is selected via the /sys/kernel/debug/nfsd/io_cache_write experimental tunable, split incoming unaligned NFS WRITE requests into a prefix, middle and suffix segment, as needed. The middle segment is now DIO-aligned and the prefix and/or suffix are unaligned. Synchronous buffered IO is used for the unaligned segments, and IOCB_DIRECT is used for the middle DIO-aligned extent. Although IOCB_DIRECT avoids the use of the page cache, by itself it doesn't guarantee data durability. For UNSTABLE WRITE requests, durability is obtained by a subsequent NFS COMMIT request. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Co-developed-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-11-11 09:59:31 -05:00
NFSD: Add io_cache_{read,write} controls to debugfs Add 'io_cache_read' to NFSD's debugfs interface so that any data read by NFSD will either be: - cached using page cache (NFSD_IO_BUFFERED=0) - cached but removed from the page cache upon completion (NFSD_IO_DONTCACHE=1). io_cache_read may be set by writing to: /sys/kernel/debug/nfsd/io_cache_read Add 'io_cache_write' to NFSD's debugfs interface so that any data written by NFSD will either be: - cached using page cache (NFSD_IO_BUFFERED=0) - cached but removed from the page cache upon completion (NFSD_IO_DONTCACHE=1). io_cache_write may be set by writing to: /sys/kernel/debug/nfsd/io_cache_write The default value for both settings is NFSD_IO_BUFFERED, which is NFSD's existing behavior for both read and write. Changes to these settings take immediate effect for all exports and NFS versions. Currently only xfs and ext4 implement RWF_DONTCACHE. For file systems that do not implement RWF_DONTCACHE, NFSD use only buffered I/O when the io_cache setting is NFSD_IO_DONTCACHE. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-09-06 17:25:11 -04:00
NFSD: Add /sys/kernel/debug/nfsd Create a small sandbox under /sys/kernel/debug for experimental NFS server feature settings. There is no API/ABI compatibility guarantee for these settings. The only documentation for such settings, if any documentation exists, is in the kernel source code. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-03-08 15:14:37 -05:00
NFSD: Add experimental setting to disable the use of splice read NFSD currently has two separate code paths for handling read requests. One uses page splicing; the other is a traditional read based on an iov iterator. Because most Linux file systems support splice read, the latter does not get nearly the same test experience as splice reads. To force the use of vectored reads for testing and benchmarking, introduce the ability to disable splice reads for all NFS READ operations. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-03-08 15:14:38 -05:00
NFSD: Add io_cache_{read,write} controls to debugfs Add 'io_cache_read' to NFSD's debugfs interface so that any data read by NFSD will either be: - cached using page cache (NFSD_IO_BUFFERED=0) - cached but removed from the page cache upon completion (NFSD_IO_DONTCACHE=1). io_cache_read may be set by writing to: /sys/kernel/debug/nfsd/io_cache_read Add 'io_cache_write' to NFSD's debugfs interface so that any data written by NFSD will either be: - cached using page cache (NFSD_IO_BUFFERED=0) - cached but removed from the page cache upon completion (NFSD_IO_DONTCACHE=1). io_cache_write may be set by writing to: /sys/kernel/debug/nfsd/io_cache_write The default value for both settings is NFSD_IO_BUFFERED, which is NFSD's existing behavior for both read and write. Changes to these settings take immediate effect for all exports and NFS versions. Currently only xfs and ext4 implement RWF_DONTCACHE. For file systems that do not implement RWF_DONTCACHE, NFSD use only buffered I/O when the io_cache setting is NFSD_IO_DONTCACHE. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-09-06 17:25:11 -04:00
nfsd: add a runtime switch for disabling delegated timestamps The delegated timestamp code seems to be working well enough now that we want to make it always be built in. In the event that there are problems though, we still want to be able to disable them for debugging purposes. Add a switch to debugfs to enable them at runtime. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2026-01-26 07:10:13 -05:00
NFSD: Add /sys/kernel/debug/nfsd Create a small sandbox under /sys/kernel/debug for experimental NFS server feature settings. There is no API/ABI compatibility guarantee for these settings. The only documentation for such settings, if any documentation exists, is in the kernel source code. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-03-08 15:14:37 -05:00