97cc1025b1
This patch removes the two daemons, gfs2_scand and gfs2_glockd and replaces them with a shrinker which is called from the VM. The net result is that GFS2 responds better when there is memory pressure, since it shrinks the glock cache at the same rate as the VFS shrinks the dcache and icache. There are no longer any time based criteria for shrinking glocks, they are kept until such time as the VM asks for more memory and then we demote just as many glocks as required. There are potential future changes to this code, including the possibility of sorting the glocks which are to be written back into inode number order, to get a better I/O ordering. It would be very useful to have an elevator based workqueue implementation for this, as that would automatically deal with the read I/O cases at the same time. This patch is my answer to Andrew Morton's remark, made during the initial review of GFS2, asking why GFS2 needs so many kernel threads, the answer being that it doesn't :-) This patch is a net loss of about 200 lines of code. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
169 lines
3.6 KiB
C
169 lines
3.6 KiB
C
/*
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* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU General Public License version 2.
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*/
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/completion.h>
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#include <linux/buffer_head.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/gfs2_ondisk.h>
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#include <linux/lm_interface.h>
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#include <asm/atomic.h>
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#include "gfs2.h"
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#include "incore.h"
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#include "super.h"
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#include "sys.h"
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#include "util.h"
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#include "glock.h"
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static void gfs2_init_inode_once(void *foo)
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{
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struct gfs2_inode *ip = foo;
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inode_init_once(&ip->i_inode);
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init_rwsem(&ip->i_rw_mutex);
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INIT_LIST_HEAD(&ip->i_trunc_list);
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ip->i_alloc = NULL;
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}
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static void gfs2_init_glock_once(void *foo)
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{
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struct gfs2_glock *gl = foo;
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INIT_HLIST_NODE(&gl->gl_list);
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spin_lock_init(&gl->gl_spin);
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INIT_LIST_HEAD(&gl->gl_holders);
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gl->gl_lvb = NULL;
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atomic_set(&gl->gl_lvb_count, 0);
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INIT_LIST_HEAD(&gl->gl_lru);
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INIT_LIST_HEAD(&gl->gl_ail_list);
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atomic_set(&gl->gl_ail_count, 0);
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}
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/**
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* init_gfs2_fs - Register GFS2 as a filesystem
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*
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* Returns: 0 on success, error code on failure
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*/
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static int __init init_gfs2_fs(void)
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{
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int error;
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error = gfs2_sys_init();
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if (error)
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return error;
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error = gfs2_glock_init();
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if (error)
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goto fail;
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error = -ENOMEM;
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gfs2_glock_cachep = kmem_cache_create("gfs2_glock",
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sizeof(struct gfs2_glock),
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0, 0,
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gfs2_init_glock_once);
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if (!gfs2_glock_cachep)
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goto fail;
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gfs2_inode_cachep = kmem_cache_create("gfs2_inode",
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sizeof(struct gfs2_inode),
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0, SLAB_RECLAIM_ACCOUNT|
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SLAB_MEM_SPREAD,
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gfs2_init_inode_once);
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if (!gfs2_inode_cachep)
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goto fail;
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gfs2_bufdata_cachep = kmem_cache_create("gfs2_bufdata",
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sizeof(struct gfs2_bufdata),
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0, 0, NULL);
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if (!gfs2_bufdata_cachep)
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goto fail;
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gfs2_rgrpd_cachep = kmem_cache_create("gfs2_rgrpd",
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sizeof(struct gfs2_rgrpd),
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0, 0, NULL);
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if (!gfs2_rgrpd_cachep)
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goto fail;
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gfs2_quotad_cachep = kmem_cache_create("gfs2_quotad",
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sizeof(struct gfs2_quota_data),
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0, 0, NULL);
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if (!gfs2_quotad_cachep)
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goto fail;
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error = register_filesystem(&gfs2_fs_type);
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if (error)
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goto fail;
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error = register_filesystem(&gfs2meta_fs_type);
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if (error)
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goto fail_unregister;
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gfs2_register_debugfs();
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printk("GFS2 (built %s %s) installed\n", __DATE__, __TIME__);
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return 0;
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fail_unregister:
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unregister_filesystem(&gfs2_fs_type);
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fail:
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gfs2_glock_exit();
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if (gfs2_quotad_cachep)
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kmem_cache_destroy(gfs2_quotad_cachep);
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if (gfs2_rgrpd_cachep)
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kmem_cache_destroy(gfs2_rgrpd_cachep);
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if (gfs2_bufdata_cachep)
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kmem_cache_destroy(gfs2_bufdata_cachep);
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if (gfs2_inode_cachep)
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kmem_cache_destroy(gfs2_inode_cachep);
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if (gfs2_glock_cachep)
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kmem_cache_destroy(gfs2_glock_cachep);
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gfs2_sys_uninit();
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return error;
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}
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/**
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* exit_gfs2_fs - Unregister the file system
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*
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*/
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static void __exit exit_gfs2_fs(void)
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{
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gfs2_glock_exit();
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gfs2_unregister_debugfs();
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unregister_filesystem(&gfs2_fs_type);
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unregister_filesystem(&gfs2meta_fs_type);
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kmem_cache_destroy(gfs2_quotad_cachep);
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kmem_cache_destroy(gfs2_rgrpd_cachep);
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kmem_cache_destroy(gfs2_bufdata_cachep);
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kmem_cache_destroy(gfs2_inode_cachep);
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kmem_cache_destroy(gfs2_glock_cachep);
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gfs2_sys_uninit();
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}
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MODULE_DESCRIPTION("Global File System");
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MODULE_AUTHOR("Red Hat, Inc.");
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MODULE_LICENSE("GPL");
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module_init(init_gfs2_fs);
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module_exit(exit_gfs2_fs);
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