Messages in this thread | | | Date | Thu, 8 Apr 2021 12:56:01 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 0/11 v2] Use local_lock for pcp protection and reduce stat overhead |
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On Wed, Apr 07, 2021 at 09:24:12PM +0100, Mel Gorman wrote: > Why local_lock? PREEMPT_RT considers the following sequence to be unsafe > as documented in Documentation/locking/locktypes.rst > > local_irq_disable(); > raw_spin_lock(&lock);
Almost, the above is actually OK on RT. The problematic one is:
local_irq_disable(); spin_lock(&lock);
That doesn't work on RT since spin_lock() turns into a PI-mutex which then obviously explodes if it tries to block with IRQs disabled.
And it so happens, that's exactly the one at hand.
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