Sir, On Tue, Feb 15, 2011 at 4:16 PM, Mulyadi Santosa <[email protected]>wrote:
> Hi... :) > > On Tue, Feb 15, 2011 at 16:08, Darshan Ghumare > <[email protected]> wrote: > > Sir, > > On x86 UP (Single CPU), Can lower priority (say) IRQ5 preempt higher one > > (say) IRQ4 (Currently, CPU is executing interrupt handler of IRQ4)? > > In Linux kernel, I never heard such irq prioritizing. Linux kernel > does general preemption such that any code path could preempt other > code path as long as preemption is allowed at that point and/or > interrupt is enabled (which one affect the situation depends on type > of code path). > IMHO, When the Processor is executing interrupt handler of IRQ4 then Processor is the one which pushes SS, SP, EFLAGS, CS & EIP on stack (in this case this will all corresponds to interrupt handler of IRQ4) & loads CS & EIP corresponding to IRQ5. So, how come its depends on OS (kernel)? Please correct me if I am wrong. > But, vaguely I read that Windows kernel does that.... that's why in > certain BSOD you read message prefixed with "IRQL xxx xxx xxxx". That > means lower interrupt handler somehow preempt higher one and that's > not allowed. > > It comes from my raw observation so things might be wrong somewhere... > > -- > regards, > > Mulyadi Santosa > Freelance Linux trainer and consultant > > blog: the-hydra.blogspot.com > training: mulyaditraining.blogspot.com >
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