OpenZFS 7303 - dynamic metaslab selection

This change introduces a new weighting algorithm to improve
metaslab selection. The new weighting algorithm relies on the
SPACEMAP_HISTOGRAM feature. As a result, the metaslab weight
now encodes the type of weighting algorithm used (size-based
vs segment-based).

Porting Notes: The metaslab allocation tracing code is conditionally
removed on linux (dependent on mdb debugger).

Authored by: George Wilson <george.wilson@delphix.com>
Reviewed by: Alex Reece <alex@delphix.com>
Reviewed by: Chris 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: Pavel Zakharov pavel.zakharov@delphix.com
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Don Brady <don.brady@intel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: Don Brady <don.brady@intel.com>

OpenZFS-issue: https://www.illumos.org/issues/7303
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/d5190931bd
Closes #5404
This commit is contained in:
Don Brady
2017-01-12 12:52:56 -07:00
committed by Brian Behlendorf
parent 5727b00e06
commit 4e21fd060a
13 changed files with 1042 additions and 226 deletions
+24
View File
@@ -179,6 +179,30 @@ relative to the pool.
Use \fB1\fR for yes (default) and \fB0\fR for no.
.RE
.sp
.ne 2
.na
\fBzfs_metaslab_segment_weight_enabled\fR (int)
.ad
.RS 12n
Enable/disable segment-based metaslab selection.
.sp
Use \fB1\fR for yes (default) and \fB0\fR for no.
.RE
.sp
.ne 2
.na
\fBzfs_metaslab_switch_threshold\fR (int)
.ad
.RS 12n
When using segment-based metaslab selection, continue allocating
from the active metaslab until \fBlzfs_metaslab_switch_threshold\fR
worth of buckets have been exhausted.
.sp
Default value: \fB2\fR.
.RE
.sp
.ne 2
.na