Messages in this thread | | | Subject | Re: [Patch for review] BSD accounting IO stats | From | Andi Kleen <> | Date | Mon, 02 Aug 2004 14:44:03 +0200 |
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Guillaume Thouvenin <guillaume.thouvenin@bull.net> writes:
> diff -uprN -X dontdiff linux-2.6.8-rc2/drivers/block/ll_rw_blk.c linux-2.6.8-rc2+BSDacct_IO/drivers/block/ll_rw_blk.c > --- linux-2.6.8-rc2/drivers/block/ll_rw_blk.c 2004-07-18 06:57:42.000000000 +0200 > +++ linux-2.6.8-rc2+BSDacct_IO/drivers/block/ll_rw_blk.c 2004-07-27 09:17:33.149321480 +0200 > @@ -1949,10 +1949,12 @@ void drive_stat_acct(struct request *rq, > > if (rw == READ) { > disk_stat_add(rq->rq_disk, read_sectors, nr_sectors); > + current->rblk += nr_sectors;
This doesn't look very useful, because most writes which are flushed delayed would get accounted to pdflushd. Using such inaccurate data for accounting sounds quite dangerous to me.
If you really wanted to do this i guess you would need to track the pid of the process and account it there. But the process may be already gone, so it would better fit into some other longer lived data structure (like the uid)
Overall I don't think this accounting is worth it because doing it right would be quite some overhead and doing it in a simple way like this patch is too inaccurate.
-Andi
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