Linux 4.14 compat: blk_queue_stackable() #7645
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The blk_queue_stackable() function was replaced in the 4.14 kernel by queue_is_rq_based(), commit torvalds/linux@5fdee212. This change resulted in the default elevator being used which can negatively impact performance. Rather than adding additional compatibility code to detect the new interface unconditionally attempt to set the elevator. Since we expect this to fail for block devices without an elevator the error message has been moved in to zfs_dbgmsg(). Finally, it was observed that the elevator_change() was removed from the 4.12 kernel, commit torvalds/linux@c033269. Update the comment to clearly specify which are expected to export the elevator_change() symbol. Signed-off-by: Brian Behlendorf <[email protected]>
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ahrens
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Jun 19, 2018
tonyhutter
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Jun 19, 2018
Codecov Report
@@ Coverage Diff @@
## master #7645 +/- ##
==========================================
- Coverage 77.52% 77.49% -0.03%
==========================================
Files 363 363
Lines 110519 110517 -2
==========================================
- Hits 85683 85650 -33
- Misses 24836 24867 +31
Continue to review full report at Codecov.
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Aug 15, 2018
The blk_queue_stackable() function was replaced in the 4.14 kernel by queue_is_rq_based(), commit torvalds/linux@5fdee212. This change resulted in the default elevator being used which can negatively impact performance. Rather than adding additional compatibility code to detect the new interface unconditionally attempt to set the elevator. Since we expect this to fail for block devices without an elevator the error message has been moved in to zfs_dbgmsg(). Finally, it was observed that the elevator_change() was removed from the 4.12 kernel, commit torvalds/linux@c033269. Update the comment to clearly specify which are expected to export the elevator_change() symbol. Reviewed-by: Matthew Ahrens <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes openzfs#7645
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Aug 23, 2018
The blk_queue_stackable() function was replaced in the 4.14 kernel by queue_is_rq_based(), commit torvalds/linux@5fdee212. This change resulted in the default elevator being used which can negatively impact performance. Rather than adding additional compatibility code to detect the new interface unconditionally attempt to set the elevator. Since we expect this to fail for block devices without an elevator the error message has been moved in to zfs_dbgmsg(). Finally, it was observed that the elevator_change() was removed from the 4.12 kernel, commit torvalds/linux@c033269. Update the comment to clearly specify which are expected to export the elevator_change() symbol. Reviewed-by: Matthew Ahrens <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes openzfs#7645
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Aug 27, 2018
The blk_queue_stackable() function was replaced in the 4.14 kernel by queue_is_rq_based(), commit torvalds/linux@5fdee212. This change resulted in the default elevator being used which can negatively impact performance. Rather than adding additional compatibility code to detect the new interface unconditionally attempt to set the elevator. Since we expect this to fail for block devices without an elevator the error message has been moved in to zfs_dbgmsg(). Finally, it was observed that the elevator_change() was removed from the 4.12 kernel, commit torvalds/linux@c033269. Update the comment to clearly specify which are expected to export the elevator_change() symbol. Reviewed-by: Matthew Ahrens <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes openzfs#7645
tonyhutter
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Sep 5, 2018
The blk_queue_stackable() function was replaced in the 4.14 kernel by queue_is_rq_based(), commit torvalds/linux@5fdee212. This change resulted in the default elevator being used which can negatively impact performance. Rather than adding additional compatibility code to detect the new interface unconditionally attempt to set the elevator. Since we expect this to fail for block devices without an elevator the error message has been moved in to zfs_dbgmsg(). Finally, it was observed that the elevator_change() was removed from the 4.12 kernel, commit torvalds/linux@c033269. Update the comment to clearly specify which are expected to export the elevator_change() symbol. Reviewed-by: Matthew Ahrens <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes openzfs#7645
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Description
The
blk_queue_stackable()function was replaced in the 4.14 kernel byqueue_is_rq_based(), commit torvalds/linux@5fdee212. This change resulted in the default elevator being used which can negativelyimpact performance.
Rather than adding additional compatibility code to detect the new interface unconditionally attempt to set the elevator. Since we expect this to fail for block devices without an elevator the error message has been moved in to
zfs_dbgmsg().Finally, it was observed that the
elevator_change()was removed from the 4.12 kernel, commit torvalds/linux@c033269. Update the comment to clearly specify which are expected to export theelevator_change() symbol.
Motivation and Context
Setting the scheduler to noop is important to maintain good performance for many workloads.
How Has This Been Tested?
Locally built, and expected performance improvement verified by @ahrens.
Types of changes
Checklist:
Signed-off-by.