Re: [4.2, Regression] Queued spinlocks cause major XFS performance regression

From: Waiman Long
Date: Wed Sep 09 2015 - 22:11:57 EST


On 09/04/2015 11:54 AM, Peter Zijlstra wrote:
On Fri, Sep 04, 2015 at 05:30:35PM +0200, Peter Zijlstra wrote:
Should I place the virt_spin_lock() thing under CONFIG_PARAVIRT (maybe
even _SPINLOCKS) such that only paravirt enabled kernels when ran on a
hypervisor that does not support paravirt patching (HyperV, VMware,
etc..) revert to the test-and-set?
Ah, CONFIG_HYPERVISOR_GUEST seems fitting, that's a prerequisite for all
the PARAVIRT options too.


Yes, I also used that in my queued unfair lock patch.

Cheers,
Longman
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