From 3699e3a44bf56e0cd58c97e8655f375ad9b65d9d Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Wed, 17 Jan 2007 15:09:20 +0000 Subject: [GFS2] Clean up/speed up readdir 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 --- fs/gfs2/sys.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'fs/gfs2/sys.c') diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c index 983eaf1e06be..cd28f08b244c 100644 --- a/fs/gfs2/sys.c +++ b/fs/gfs2/sys.c @@ -436,7 +436,6 @@ TUNE_ATTR(atime_quantum, 0); TUNE_ATTR(max_readahead, 0); TUNE_ATTR(complain_secs, 0); TUNE_ATTR(reclaim_limit, 0); -TUNE_ATTR(prefetch_secs, 0); TUNE_ATTR(statfs_slow, 0); TUNE_ATTR(new_files_jdata, 0); TUNE_ATTR(new_files_directio, 0); @@ -465,7 +464,6 @@ static struct attribute *tune_attrs[] = { &tune_attr_max_readahead.attr, &tune_attr_complain_secs.attr, &tune_attr_reclaim_limit.attr, - &tune_attr_prefetch_secs.attr, &tune_attr_statfs_slow.attr, &tune_attr_quota_simul_sync.attr, &tune_attr_quota_cache_secs.attr, -- cgit v1.2.3