Well, seems like you have to also learn to google, since I found the answer to all your questions within seconds. Pol On 08.8.14 21:16, Nick Krause wrote:
For the last few days , I have been reading the code for do_fork and other parts of the scheduler code. As most of the developers feel this is in my best interest. I do however have a few questions about the code for the function, schedule. 1. In task struct we have this one defined if needed 1481 #ifdef CONFIG_BLOCK 1482 /* stack plugging */ 1483 struct blk_plug *plug; 1484 #endif I am curious is this used for block IO or something else as we are checking for it in schedule() with this line, sched_submit_work(tsk); which in turn points to sched_submit_work and in turn checks for blk_plug 2814 static inline void sched_submit_work(struct task_struct *tsk) 2815 { 2816 if (!tsk->state || tsk_is_pi_blocked(tsk)) 2817 return; 2818 /* 2819 * If we are going to sleep and we have plugged IO queued, 2820 * make sure to submit it to avoid deadlocks. 2821 */ 2822 if (blk_needs_flush_plug(tsk)) 2823 blk_schedule_flush_plug(tsk); 2824 } Since schedule returns this and after searching using lxr, can't find much on this, what is this type actually defined as when compiled? 368 #define __sched __attribute__((__section__(".sched.text"))) 3. context_switch(rq, prev, next); /* unlocks the rq */ I am getting confused by this function after tracing it, if someone wants to explain it to me that would be great.
In addition I am not not trying to turn this into a self help just for me, but my questions about git I goggled for 2 hours and didn't
find any answers, sorry about that guys. In addition I hope theses questions are valid. Cheers Nick