Messages in this thread | | | Date | Fri, 18 Jan 2008 14:01:14 +0800 | From | Fengguang Wu <> | Subject | Re: [patch] Converting writeback linked lists to a tree based data structure |
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On Fri, Jan 18, 2008 at 06:41:09AM +0100, Andi Kleen wrote: > Fengguang Wu <wfg@mail.ustc.edu.cn> writes: > > > > Suppose we want to grant longer expiration window for temp files, > > adding a new list named s_dirty_tmpfile would be a handy solution. > > How would the kernel know that a file is a tmp file?
No idea - but it makes a good example ;-)
But for those making different filesystems for /tmp, /var, /data etc, per-superblock expiration parameters may help.
> > So the question is: should we need more than 3 QoS classes? > > [just a random idea; i have not worked out all the implications] > > Would it be possible to derive a writeback apriority from the ionice > level of the process originating the IO? e.g. we have long standing > problems that background jobs even when niced and can cause > significant slow downs to foreground processes by starving IO > and pushing out pages. ionice was supposed to help with that > but in practice it does not seem to have helped too much and I suspect > it needs more prioritization higher up the VM food chain. Adding > such priorities to writeback would seem like a step in the right > direction, although it would of course not solve the problem > completely.
Good idea. Michael may well be considering similar interfaces :-)
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