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Don Brady 3dfb57a35e OpenZFS 7090 - zfs should throttle allocations
OpenZFS 7090 - zfs should throttle allocations

Authored by: George Wilson <george.wilson@delphix.com>
Reviewed by: Alex Reece <alex@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <paul.dagnelie@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Sebastien Roy <sebastien.roy@delphix.com>
Approved by: Matthew Ahrens <mahrens@delphix.com>
Ported-by: Don Brady <don.brady@intel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>

When write I/Os are issued, they are issued in block order but the ZIO
pipeline will drive them asynchronously through the allocation stage
which can result in blocks being allocated out-of-order. It would be
nice to preserve as much of the logical order as possible.

In addition, the allocations are equally scattered across all top-level
VDEVs but not all top-level VDEVs are created equally. The pipeline
should be able to detect devices that are more capable of handling
allocations and should allocate more blocks to those devices. This
allows for dynamic allocation distribution when devices are imbalanced
as fuller devices will tend to be slower than empty devices.

The change includes a new pool-wide allocation queue which would
throttle and order allocations in the ZIO pipeline. The queue would be
ordered by issued time and offset and would provide an initial amount of
allocation of work to each top-level vdev. The allocation logic utilizes
a reservation system to reserve allocations that will be performed by
the allocator. Once an allocation is successfully completed it's
scheduled on a given top-level vdev. Each top-level vdev maintains a
maximum number of allocations that it can handle (mg_alloc_queue_depth).
The pool-wide reserved allocations (top-levels * mg_alloc_queue_depth)
are distributed across the top-level vdevs metaslab groups and round
robin across all eligible metaslab groups to distribute the work. As
top-levels complete their work, they receive additional work from the
pool-wide allocation queue until the allocation queue is emptied.

OpenZFS-issue: https://www.illumos.org/issues/7090
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/4756c3d7
Closes #5258 

Porting Notes:
- Maintained minimal stack in zio_done
- Preserve linux-specific io sizes in zio_write_compress
- Added module params and documentation
- Updated to use optimize AVL cmp macros
2016-10-13 17:59:18 -07:00
cmd Fix coverity defects: CID 147606, 147609 2016-10-12 11:16:47 -07:00
config Explicit block device plugging when submitting multiple BIOs 2016-09-29 13:13:31 -07:00
contrib Use a different technique to detect whether to mount-zfs 2016-10-06 10:26:47 -07:00
etc Change /etc/mtab to /proc/self/mounts 2016-09-20 10:07:58 -07:00
include OpenZFS 7090 - zfs should throttle allocations 2016-10-13 17:59:18 -07:00
lib Fix coverity defects: CID 147654, 147690 2016-10-13 14:02:07 -07:00
man OpenZFS 7090 - zfs should throttle allocations 2016-10-13 17:59:18 -07:00
module OpenZFS 7090 - zfs should throttle allocations 2016-10-13 17:59:18 -07:00
rpm OpenZFS - Performance regression suite for zfstest 2016-09-08 16:18:28 -07:00
scripts Add icp kernel module to dkms build 2016-10-06 10:31:42 -07:00
tests Fix coverity defects: CID 147692, 147693, 147694 2016-10-13 14:38:59 -07:00
udev Set proper dependency for string replacement targets 2016-08-02 10:28:29 -07:00
.gitignore Illumos Crypto Port module added to enable native encryption in zfs 2016-07-20 10:43:30 -07:00
.gitmodules Add zimport.sh compatibility test script 2014-02-21 12:10:31 -08:00
AUTHORS Add a missing > to AUTHORS 2014-09-02 14:18:53 -07:00
autogen.sh build: do not call boilerplate ourself 2013-04-02 10:55:20 -07:00
configure.ac Add support for user/group dnode accounting & quota 2016-10-07 09:45:13 -07:00
copy-builtin Illumos Crypto Port module added to enable native encryption in zfs 2016-07-20 10:43:30 -07:00
COPYRIGHT Update ZED copyright boilerplate 2015-05-11 15:07:00 -07:00
DISCLAIMER Fix minor typos and update marketing copy. 2013-03-21 12:51:06 -07:00
Makefile.am Introduce a make recipe for flake8 2016-10-06 10:52:21 -07:00
META Tag 0.7.0-rc1 2016-09-07 10:31:23 -07:00
OPENSOLARIS.LICENSE Add CDDL license file 2008-12-01 14:49:34 -08:00
README.markdown Fix minor typos and update marketing copy. 2013-03-21 12:51:06 -07:00
TEST Add the ZFS Test Suite 2016-03-16 13:46:16 -07:00
zfs-script-config.sh.in Introduce tests for python scripts 2016-10-06 13:11:57 -07:00
zfs.release.in Move zfs.release generation to configure step 2012-07-12 12:22:51 -07:00

Native ZFS for Linux!

ZFS is an advanced file system and volume manager which was originally developed for Solaris and is now maintained by the Illumos community.

ZFS on Linux, which is also known as ZoL, is currently feature complete. It includes fully functional and stable SPA, DMU, ZVOL, and ZPL layers.

Full documentation for installing ZoL on your favorite Linux distribution can be found at: http://zfsonlinux.org