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1218149037
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>
48 lines
1.0 KiB
C
48 lines
1.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/debugfs.h>
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#include "nfsd.h"
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static struct dentry *nfsd_top_dir __read_mostly;
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/*
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* /sys/kernel/debug/nfsd/disable-splice-read
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*
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* Contents:
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* %0: NFS READ is allowed to use page splicing
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* %1: NFS READ uses only iov iter read
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*
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* The default value of this setting is zero (page splicing is
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* allowed). This setting takes immediate effect for all NFS
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* versions, all exports, and in all NFSD net namespaces.
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*/
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static int nfsd_dsr_get(void *data, u64 *val)
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{
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*val = nfsd_disable_splice_read ? 1 : 0;
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return 0;
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}
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static int nfsd_dsr_set(void *data, u64 val)
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{
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nfsd_disable_splice_read = (val > 0) ? true : false;
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return 0;
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}
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DEFINE_DEBUGFS_ATTRIBUTE(nfsd_dsr_fops, nfsd_dsr_get, nfsd_dsr_set, "%llu\n");
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void nfsd_debugfs_exit(void)
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{
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debugfs_remove_recursive(nfsd_top_dir);
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nfsd_top_dir = NULL;
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}
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void nfsd_debugfs_init(void)
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{
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nfsd_top_dir = debugfs_create_dir("nfsd", NULL);
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debugfs_create_file("disable-splice-read", S_IWUSR | S_IRUGO,
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nfsd_top_dir, NULL, &nfsd_dsr_fops);
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}
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