On Sun, Feb 10, 2013 at 12:22 AM, Frederic Weisbecker <fweis...@gmail.com>wrote:
> 2013/2/9 Peter Teoh <htmldevelo...@gmail.com>: > > A search in the entire subtree of arch/x86/ and including all its > > subdirectories, (for 3.2.0 kernel) return only TWO result where > > preempt_schedule_irq is called: kernel/entry_64.S and > kernel/entry_32.S. > > And the called is in fact resume_kernel(), ie, it is NOT called from > timer > > interrupt, but from wakeup context of the CPU, and is only executed ONCE > > upon waking up from hibernation. > > > > for example, calling from here: > > > > https://lkml.org/lkml/2012/5/2/298 > > > > so definitely this preempt_schedule_irq() calling from irq mode is rare > - at > > least for x86. > > The name "resume_kernel" can indeed sound like something that is > called on hibernation resume. It's actually not related at all. It's a > piece of code that is called at the end of every irq and exception > when the interrupted code was running in the kernel. If the > interrupted code was running in userspace, we jump to > resume_userspace. > well, i guessed u must be the expert here, i have yet to really digest all these...:-). thanks for the explanation. -- Regards, Peter Teoh
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