Messages in this thread | | | Date | Mon, 26 Oct 2015 10:48:54 +0000 | From | Russell King - ARM Linux <> | Subject | Re: How is jiffies upation while holding spinlock in Uniprocessor or SMP environment? |
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On Mon, Oct 26, 2015 at 12:19:31PM +0530, raghu MG wrote: > Hello, > I have couple of questions. > 1) In case of UP how is jiffies(timer) get updated while holding spin > lock using spinlock_irq_save?
It isn't, and... > > 2)My understanding is in smp environment jiffies updation cannot be > done on processor holding spinlock irrespective of spinlock API.So > timer interrupt should be enabled across all cores in SoC. Imagine a > scenario in quad core processor where 4 cores are holding 4 different > spinlocks & how is the timer interrupt for jiffies handled?
You can't rely on jiffies being updated while holding a spinlock. Expecting jiffies to update while holding a spinlock is a bug.
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