Hi, > On Tue, 2004-04-06 at 13:50, Eugene Crosser wrote: > > More representative statistics for my "quota on ext3" trouble: > > > > after moving about 10,000 files and setting quota for a million > > groupids, and then several hours of inactivity(!) I zeroed profile > > counters (readprofile -r), ran `time sync' and then `readprofile'. Here > > are the results. Yes, that's true, it took 3 (three) hours for `sync' > > to complete! > > Turns out there's a nasty O(N^2) behaviour in vfs_quota_sync(). That > function walks the dquot list looking for things to sync, and it drops > the lock when doing the actual syncing --- so each item synced causes it > to start again at the beginning of the list. If each item starts off > dirty, then the list walk is N^2. > > An obvious cure is to shift the start of the list to point just after > the item just synced. I've done only limited testing of this patch, but > does it help for you? > > 2.4 and 2.6 seem to share this problem. Yes, both 2.4 and 2.6 have this problem. I've just never seen it reported. Your fix should work although it relies a bit on the fact that there are no other users of inuse list which would be non-atomical... I'll try to think of something which would not rely on this fact and is reasonably easy to implement. Thanks for fix Honza _______________________________________________ Ext3-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/ext3-users
