6b82021b9e
I have observed that the current size of 8M gives us pretty poor fragmentation on multi-threaded workloads which do lots of writes. Generally, I can increase the size of local alloc windows and observe a marked decrease in fragmentation, even up and beyond window sizes of 512 megabytes. This makes sense for a couple reasons - larger local alloc means more room for reservation windows. On multi-node workloads the larger local alloc helps as well because we don't have to do window slides as often. Also, I removed the OCFS2_DEFAULT_LOCAL_ALLOC_SIZE constant as it is no longer used and the comment above it was out of date. To test fragmentation, I used a workload which launched 4 threads that did 4k writes into a series of about 140 alternating files. With resv_level=2, and a 4k/4k file system I observed the following average fragmentation for various localalloc= parameters: localalloc= avg. fragmentation 8 48 32 16 64 10 120 7 On larger cluster sizes, the difference is more dramatic. The new default size top out at 256M, which we'll only get for cluster sizes of 32K and above. Signed-off-by: Mark Fasheh <mfasheh@suse.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
63 lines
2.0 KiB
C
63 lines
2.0 KiB
C
/* -*- mode: c; c-basic-offset: 8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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*
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* localalloc.h
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*
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* Function prototypes
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*
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* Copyright (C) 2002, 2004 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#ifndef OCFS2_LOCALALLOC_H
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#define OCFS2_LOCALALLOC_H
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int ocfs2_load_local_alloc(struct ocfs2_super *osb);
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void ocfs2_shutdown_local_alloc(struct ocfs2_super *osb);
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void ocfs2_la_set_sizes(struct ocfs2_super *osb, int requested_mb);
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unsigned int ocfs2_la_default_mb(struct ocfs2_super *osb);
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int ocfs2_begin_local_alloc_recovery(struct ocfs2_super *osb,
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int node_num,
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struct ocfs2_dinode **alloc_copy);
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int ocfs2_complete_local_alloc_recovery(struct ocfs2_super *osb,
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struct ocfs2_dinode *alloc);
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int ocfs2_alloc_should_use_local(struct ocfs2_super *osb,
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u64 bits);
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struct ocfs2_alloc_context;
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int ocfs2_reserve_local_alloc_bits(struct ocfs2_super *osb,
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u32 bits_wanted,
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struct ocfs2_alloc_context *ac);
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int ocfs2_claim_local_alloc_bits(struct ocfs2_super *osb,
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handle_t *handle,
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struct ocfs2_alloc_context *ac,
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u32 bits_wanted,
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u32 *bit_off,
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u32 *num_bits);
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void ocfs2_local_alloc_seen_free_bits(struct ocfs2_super *osb,
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unsigned int num_clusters);
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void ocfs2_la_enable_worker(struct work_struct *work);
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#endif /* OCFS2_LOCALALLOC_H */
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