On Wednesday 19 March 2008 13:23, Mike Snitzer wrote:
Hi Mike,
OK, this is committed now, but caveat: improved, untested except for
booting. But what could possibly go wrong? :-/
http://phunq.net/ddtree?p=ddtree/.git;a=blob;f=patches/bio-throttle
The production version is sitting in the code.google.com svn repository
in ddsnap/patches/2.6.23.8. That one has a known bug that has somehow
escaped being stomped with a new commit, since it only manifests if you
stack one stacking block device on top of another one. I will post here
when we have an official, torture tested version of the patch.
The patch above is improved from the most recently posted version by
using using the ->bi_max_vecs field for throttle accounting instead of
calling out to a per-driver metric. This works nicely because the
max_vecs field cannot change during the life of the bio, and it gives
a decent upper bound on the resource consumption of the bio, better
than simply counting bios in flight. The queue->metric() method is
still in there as a stub, some more cleanup to do there (and further
shrinking of the patch). It does no harm.
This improvement shrinks the throttled version of struct bio by 4
bytes.
Regards,
Daniel
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