On Sat, Jan 19, 2013 at 01:08:47PM -0600, Mark Tinguely wrote: > On 01/10/13 07:47, Jeff Liu wrote: > >Start to make use of the new helper to figure out space log reservations for those > >transactions which are pre-calculated at mount time in xfs_trans.c. > > > >Signed-off-by: Jie Liu<jeff.liu@xxxxxxxxxx> > >--- > > fs/xfs/xfs_trans.c | 244 ++++++++++++++++++++++++---------------------------- > > 1 file changed, 113 insertions(+), 131 deletions(-) > > > > Wow! Reading this patch makes me appreciate the work you did here > and gets my eyes in shape for Dave's UBER user sync patch. > > A question for you, or anyone. When these reservations are made, the > comments talk about specify number of agf/agfl (usually 2 or 3) that > will be dirty in the command. > > There are other comments that seem to imply an agf/agfl is reserved > for all AGs and then use the multiplier of 4. Is a specific number > of AGs can be involved in the operation or does it want something > like sb_agcount? Do you mean comments like this about xfs_calc_itruncate_reservation()? * And the bmap_finish transaction can free the blocks and bmap * blocks: * the agf for each of the ags: 4 * sector size * the agfl for each of the ags: 4 * sector size This assumes the transaction can free 4 extents before a commit, and all 4 extents can be in a different AG. You'll find all the other cases documented like this indicate how many extents can be freed or allocated in a single transaction.... > I think there a couple error (may be more): At a quick glance, it's hard to verify if there are errors or not. I was about to suggest that you do this: > I will have to go through this patch again and also test prints > before and after the patch. > > Before the patch: > write 108216 itrnc 219064 renam 305976 link 153144 remov 153144 > symlk 158520 creat 157880 > mkdir 157880 ifree 57912 ichng 1592 grwdt 44160 swrit 384 wrtid 384 > addfk 69560 > atriv 174720 attst 22456 attrr 87992 clagi 640 gwall 65024 grezr > 4224 gwrfr 5760 > > > After the patch: > write 108216 itrnc 255928 renam 305976 link 153144 remov 153144 > symlk 158520 creat 153784 > mkdir 153784 ifree 57784 ichng 1592 grwdt 44160 swrit 384 wrtid 384 > addfk 69560 > atriv 174720 attst 22456 attrr 87992 clagi 640 gwall 65024 grezr > 4224 gwrfr 5760 But it looks like you've already thought of that :) I'd also suggest that different geometries need to be checked, because things like block size affect the result. I'd be looking at checking these geometries: -b size=512 -n size=512 -b size=512 -n size=4096 -b size=512 -n size=65536 -b size=4096 -n size=4096 -b size=4096 -n size=65536 -b size=4096 -n size=4096 -i size=2048 Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
