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Matthew Ahrens be5c6d9653
Only examine best metaslabs on each vdev
On a system with very high fragmentation, we may need to do lots of gang
allocations (e.g. most indirect block allocations (~50KB) may need to
gang). Before failing a "normal" allocation and resorting to ganging, we
try every metaslab.  This has the impact of loading every metaslab (not
a huge deal since we now typically keep all metaslabs loaded), and also
iterating over every metaslab for every failing allocation. If there are
many metaslabs (more than the typical ~200, e.g. due to vdev expansion
or very large vdevs), the CPU cost of this iteration can be very
impactful.  This iteration is done with the mg_lock held, creating long
hold times and high lock contention for concurrent allocations,
ultimately causing long txg sync times and poor application performance.

To address this, this commit changes the behavior of "normal" (not
try_hard, not ZIL) allocations.  These will now only examine the 100
best metaslabs (as determined by their ms_weight).  If none of these
have a large enough free segment, then the allocation will fail and
we'll fall back on ganging.

To accomplish this, we will now (normally) gang before doing a
`try_hard` allocation.  Non-try_hard allocations will only examine the
100 best metaslabs of each vdev.  In summary, we will first try normal
allocation.  If that fails then we will do a gang allocation.  If that
fails then we will do a "try hard" gang allocation.  If that fails then
we will have a multi-layer gang block.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #11327
2020-12-16 14:40:05 -08:00
.github CI: add zloop workflow 2020-12-10 20:46:15 +03:00
cmd Make metaslab class rotor and aliquot per-allocator. 2020-12-15 10:55:44 -08:00
config Implement memory and CPU hotplug 2020-12-10 14:09:23 -08:00
contrib dracut: use /bin/sh instead of bash as the intepreter 2020-11-28 11:02:08 -08:00
etc Verify zfs module loaded before starting services 2020-11-28 11:11:18 -08:00
include Only examine best metaslabs on each vdev 2020-12-16 14:40:05 -08:00
lib FreeBSD libzfs: gcc requires __thread after static 2020-12-14 09:28:24 -08:00
man Only examine best metaslabs on each vdev 2020-12-16 14:40:05 -08:00
module Only examine best metaslabs on each vdev 2020-12-16 14:40:05 -08:00
rpm zpool_influxdb: move to libexec dir 2020-11-28 11:15:57 -08:00
scripts DKMS: Disable weak modules 2020-12-15 09:22:30 -08:00
tests Fix reporting of CKSUM errors in indirect vdevs 2020-12-11 12:15:37 -08:00
udev Centralize variable substitution 2020-07-14 17:33:44 -07:00
.editorconfig Add an .editorconfig; document git whitespace settings 2020-01-27 13:32:52 -08:00
.gitignore Add FreeBSD support to OpenZFS 2020-04-14 11:36:28 -07:00
.gitmodules Add zimport.sh compatibility test script 2014-02-21 12:10:31 -08:00
AUTHORS Add zstd support to zfs 2020-08-20 10:30:06 -07:00
autogen.sh Cause autogen.sh to fail if autoreconf fails 2018-07-06 09:27:37 -07:00
CODE_OF_CONDUCT.md Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
configure.ac Distributed Spare (dRAID) Feature 2020-11-13 13:51:51 -08:00
copy-builtin Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
COPYRIGHT Fix typos 2020-06-09 21:24:09 -07:00
cppcheck-suppressions.txt Import ZStandard v1.4.5 2020-08-20 10:30:06 -07:00
LICENSE Update build system and packaging 2018-05-29 16:00:33 -07:00
Makefile.am dracut: use /bin/sh instead of bash as the intepreter 2020-11-28 11:02:08 -08:00
META Increase Supported Linux Kernel to 5.9 2020-10-13 09:51:13 -07:00
NEWS Fix NEWS file 2020-08-26 21:44:41 -07:00
NOTICE Update build system and packaging 2018-05-29 16:00:33 -07:00
README.md docs: update README's installation link 2020-10-08 09:33:53 -07:00
TEST Remove CI builder customization from TEST 2020-03-16 10:46:03 -07:00
zfs.release.in Move zfs.release generation to configure step 2012-07-12 12:22:51 -07:00

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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.

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Official Resources

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 META file contains the officially recognized supported Linux kernel versions.
  • Supported FreeBSD versions are 12-STABLE and 13-CURRENT.