Reduce ARC fragmentaion threshold
ClosedPublic

Authored by smh on Mar 15 2017, 12:40 PM.

Details

Summary

As ZFS can request up to SPA_MAXBLOCKSIZE memory block e.g. during zfs recv, update the threshold at which we start agressive reclamation to use SPA_MAXBLOCKSIZE (16M) instead of the lower zfs_max_recordsize which defaults to 1M.

This was reported here:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=194513

Diff Detail

Repository
rS FreeBSD src repository
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.
smh created this revision.Mar 15 2017, 12:40 PM
smh added a reviewer: mav.Mar 15 2017, 12:40 PM
mav accepted this revision.EditedMar 15 2017, 12:45 PM

I have no objections. It may be too aggressive if fragmentation was somehow caused not by ZFS, but any way I don't know any other place in system which would bother to do this, while I know other places that suffer quietly from fragmentation.

This revision is now accepted and ready to land.Mar 15 2017, 12:45 PM
smh added a reviewer: avg.Mar 17 2017, 12:14 PM
avg accepted this revision.Mar 17 2017, 12:22 PM
This revision was automatically updated to reflect the committed changes.