3699e3a44b
This removes the extra filldir callback which gfs2 was using to enclose an attempt at readahead for inodes during readdir. The code was too complicated and also hurts performance badly in the case that the getdents64/readdir call isn't being followed by stat() and it wasn't even getting it right all the time when it was. As a result, on my test box an "ls" of a directory containing 250000 files fell from about 7mins (freshly mounted, so nothing cached) to between about 15 to 25 seconds. When the directory content was cached, the time taken fell from about 3mins to about 4 or 5 seconds. Interestingly in the cached case, running "ls -l" once reduced the time taken for subsequent runs of "ls" to about 6 secs even without this patch. Now it turns out that there was a special case of glocks being used for prefetching the metadata, but because of the timeouts for these locks (set to 10 secs) the metadata was being timed out before it was being used and this the prefetch code was constantly trying to prefetch the same data over and over. Calling "ls -l" meant that the inodes were brought into memory and once the inodes are cached, the glocks are not disposed of until the inodes are pushed out of the cache, thus extending the lifetime of the glocks, and thus bringing down the time for subsequent runs of "ls" considerably. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
63 lines
2.0 KiB
C
63 lines
2.0 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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#ifndef __DIR_DOT_H__
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#define __DIR_DOT_H__
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#include <linux/dcache.h>
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struct inode;
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struct gfs2_inode;
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struct gfs2_inum;
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int gfs2_dir_search(struct inode *dir, const struct qstr *filename,
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struct gfs2_inum_host *inum, unsigned int *type);
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int gfs2_dir_add(struct inode *inode, const struct qstr *filename,
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const struct gfs2_inum_host *inum, unsigned int type);
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int gfs2_dir_del(struct gfs2_inode *dip, const struct qstr *filename);
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int gfs2_dir_read(struct inode *inode, u64 *offset, void *opaque,
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filldir_t filldir);
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int gfs2_dir_mvino(struct gfs2_inode *dip, const struct qstr *filename,
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struct gfs2_inum_host *new_inum, unsigned int new_type);
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int gfs2_dir_exhash_dealloc(struct gfs2_inode *dip);
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int gfs2_diradd_alloc_required(struct inode *dir,
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const struct qstr *filename);
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int gfs2_dir_get_new_buffer(struct gfs2_inode *ip, u64 block,
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struct buffer_head **bhp);
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static inline u32 gfs2_disk_hash(const char *data, int len)
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{
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return crc32_le((u32)~0, data, len) ^ (u32)~0;
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}
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static inline void gfs2_str2qstr(struct qstr *name, const char *fname)
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{
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name->name = fname;
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name->len = strlen(fname);
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name->hash = gfs2_disk_hash(name->name, name->len);
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}
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/* N.B. This probably ought to take inum & type as args as well */
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static inline void gfs2_qstr2dirent(const struct qstr *name, u16 reclen, struct gfs2_dirent *dent)
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{
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dent->de_inum.no_addr = cpu_to_be64(0);
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dent->de_inum.no_formal_ino = cpu_to_be64(0);
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dent->de_hash = cpu_to_be32(name->hash);
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dent->de_rec_len = cpu_to_be16(reclen);
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dent->de_name_len = cpu_to_be16(name->len);
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dent->de_type = cpu_to_be16(0);
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memset(dent->__pad, 0, sizeof(dent->__pad));
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memcpy(dent + 1, name->name, name->len);
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}
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#endif /* __DIR_DOT_H__ */
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