CONFIG_PREEMPT_NONE and interrupts

Dave Hylands dhylands at
Wed Jul 1 16:45:27 EDT 2015

Meant to use reply-to-all:

On Wed, Jul 1, 2015 at 10:00 AM, Sudharsan Vijayaraghavan <
sudvijayr at> wrote:
> HI All,
> Please validate my understanding regarding the following,
> While CONFIG_PREEMPT_NONE is set 1 and a process is already in kernel
> mode, interrupts to that core will not honored until it exits from
> kernel mode,

My understanding is that CONFIG_PREEMPT_NONE has nothing to do with
interrupts. Those will still happen.

But if a thread is running, then it won't be preempted by another thread
until it decides to block (as opposed to being preempted at the end of its
time slice or by an interrupt making another thread ready-to-run).

Dave Hylands
Shuswap, BC, Canada
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