mirror_zfs/module
Alexander Motin 85c43508f3 Introduce write-mostly sums
wmsum counters are a reduced version of aggsum counters, optimized for
write-mostly scenarios.  They do not provide optimized read functions,
but instead allow much cheaper add function.  The primary usage is
infrequently read statistic counters, not requiring exact precision.

The Linux implementation is directly mapped into percpu_counter KPI.
The FreeBSD implementation is directly mapped into counter(9) KPI.
In user-space due to lack of better implementation mapped to aggsum.

Unfortunately neither Linux percpu_counter nor FreeBSD counter(9)
provide sufficient functionality to completelly replace aggsum, so
it still remains to be used for several hot counters.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes #12114
2021-06-09 13:05:34 -07:00
..
avl
icp Replace ZoL with OpenZFS where applicable 2021-05-10 12:16:46 -07:00
lua
nvpair
os Bend zpl_set_acl to permit the new userns* parameter 2021-05-27 22:31:57 -07:00
spl
unicode
zcommon
zfs Introduce write-mostly sums 2021-06-09 13:05:34 -07:00
zstd
.gitignore
Kbuild.in
Makefile.bsd
Makefile.in