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Alexander Motin
c935fe2e92
ARC code was many times significantly modified over the years, that created significant amount of tangled and potentially broken code. This should make arc_access()/arc_read() code some more readable. - Decouple prefetch status tracking from b_refcnt. It made sense originally, but became highly cryptic over the years. Move all the logic into arc_access(). While there, clean up and comment state transitions in arc_access(). Some transitions were weird IMO. - Unify arc_access() calls to arc_read() instead of sometimes calling it from arc_read_done(). To avoid extra state changes and checks add one more b_refcnt for ARC_FLAG_IO_IN_PROGRESS. - Reimplement ARC_FLAG_WAIT in case of ARC_FLAG_IO_IN_PROGRESS with the same callback mechanism to not falsely account them as hits. Count those as "iohits", an intermediate between "hits" and "misses". While there, call read callbacks in original request order, that should be good for fairness and random speculations/allocations/aggregations. - Introduce additional statistic counters for prefetch, accounting predictive vs prescient and hits vs iohits vs misses. - Remove hash_lock argument from functions not needing it. - Remove ARC_FLAG_PREDICTIVE_PREFETCH, since it should be opposite to ARC_FLAG_PRESCIENT_PREFETCH if ARC_FLAG_PREFETCH is set. We may wish to add ARC_FLAG_PRESCIENT_PREFETCH to few more places. - Fix few false positive tests found in the process. Reviewed-by: George Wilson <gwilson@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu> Reviewed-by: Ryan Moeller <ryan@iXsystems.com> Signed-off-by: Alexander Motin <mav@FreeBSD.org> Sponsored by: iXsystems, Inc. Closes #14123
OpenZFS is an advanced file system and volume manager which was originally developed for Solaris and is now maintained by the OpenZFS community. This repository contains the code for running OpenZFS on Linux and FreeBSD.
Official Resources
- Documentation - for using and developing this repo
- ZoL Site - Linux release info & links
- Mailing lists
- OpenZFS site - for conference videos and info on other platforms (illumos, OSX, Windows, etc)
Installation
Full documentation for installing OpenZFS on your favorite operating system can be found at the Getting Started Page.
Contribute & Develop
We have a separate document with contribution guidelines.
We have a Code of Conduct.
Release
OpenZFS is released under a CDDL license.
For more details see the NOTICE, LICENSE and COPYRIGHT files; UCRL-CODE-235197
Supported Kernels
- The
METAfile contains the officially recognized supported Linux kernel versions. - Supported FreeBSD versions are any supported branches and releases starting from 12.2-RELEASE.