On Mon, 8 Aug 2011 10:09:31 +0200, dexen deVries
<dexen.devries@xxxxxxxxx> wrote:
[lowering cleanerd priority]
However, may be a downside to /always/ running cleanerd niced and
ioniced. I
believe that currently cleanerd's activity slows other processes down
a lot
when filesystem is almost full -- which means that it oftet won't
become truly
full, because clearned will free enough space for other processes to
be able
to complete their work. If, on the other hand, cleanerd was highly
niced and
ioniced, it could end up being starved of CPU and disk bandwidth and
not
freeing enough free space, which could cause other processes to
exhaust free
space on filesystem and abord when not able to write to filesystem.
I was just thinking about that. This would only be an issue on a system
that is either very constrained in terms of disk space or is never idle.
though.
Perhaps it would be enough to have cleanerd automatically switch
priority
based on available free space. For example, if I had
min_clean_segments 10%
max_clean_segments 12%
then also have
min_clean_segments_low_prio 8%
low_prio_nice 19
normal_prio_nice 0
low_prio_ionice_class idle
normal_prio_ionice_class realtime
which woud mean, `use low priority (nice & ionice) when there's at
least 8% of
free segments; if there's less use higher priority' -- so cleanerd
would
reclaim free space more aggressively when there's little free space
left.
I was thinking about something similar. Realtime ionice is OTT, though,
I don't think it should ever be ioniced over normal. But yes, I think
this would be a good idea.
Gordan
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