运行中的xen(schedule方面)

运行中的dom可能会不断的调用某些schedule函数,使得pcpu与vcpu之间达到平衡

startup_cpu_idle_loop() -> continue_cpu_idle_loop() -> do_softirq()

softirq_handlers[]

open_softirq()

TIMER_SOFTIRQ -> timer_softirq_action()
SCHEDULE_SOFTIRQ -> schedule()***待续
NEW_TLBFLUSH_CLOCK_PERIOD_SOFTIRQ -> new_tlbflush_clock_period()
PAGE_SCRUB_SOFTIRQ -> page_scrub_softirq()
RCU_SOFTIRQ -> rcu_process_callbacks()
STOPMACHINE_SOFTIRQ -> stopmachine_softirq()
TASKLET_SOFTIRQ -> tasklet_action()

ia64

CMC_DISABLE_SOFTIRQ -> ia64_mca_cmc_vector_disable()
CMC_ENABLE_SOFTIRQ -> ia64_mca_cmc_vector_enable()

x86

NMI_MCE_SOFTIRQ -> nmi_mce_softirq()
TIME_CALIBRATE_SOFTIRQ -> local_time_calibration()
VCPU_KICK_SOFTIRQ -> vcpu_kick_softirq()

 xen/include/xen/softirq.h 
 /* Low-latency softirqs come first in the following list. */
 enum {
     TIMER_SOFTIRQ = 0,
     SCHEDULE_SOFTIRQ,
     NEW_TLBFLUSH_CLOCK_PERIOD_SOFTIRQ,
     PAGE_SCRUB_SOFTIRQ,
     RCU_SOFTIRQ,
     STOPMACHINE_SOFTIRQ,
     TASKLET_SOFTIRQ,
     NR_COMMON_SOFTIRQS
 };

 xen/include/asm-ia64/softirq.h 
 #define CMC_DISABLE_SOFTIRQ    (NR_COMMON_SOFTIRQS + 0)
 #define CMC_ENABLE_SOFTIRQ     (NR_COMMON_SOFTIRQS + 1)

 xen/include/asm-x86/softirq.h 
 #define NMI_MCE_SOFTIRQ        (NR_COMMON_SOFTIRQS + 0)
 #define TIME_CALIBRATE_SOFTIRQ (NR_COMMON_SOFTIRQS + 1)
 #define VCPU_KICK_SOFTIRQ      (NR_COMMON_SOFTIRQS + 2)

schedule()

schedule()何时被调用?

在xen的大循环中,do_softirq()先通过下面的过程得到cpuid
do_softirq() -> smp_processor_id() -> raw_smp_processor_id() -> get_processor_id() -> get_cpu_info()

然后用softirq_pending()取出该cpu的pending值(64bitmap),
softirq_pending() -> cpu_data() -> per_cpu() -> RELOC_HIDE()

用find_first_set_bit()宏找到第一个设置为1的位i,用clear_bit()将i位置0,然后调用softirq_handlers[i],schedule()对应的是第1个位(从0开始)

bitmap的schedule位何时被设置?

在大循环函数中,raise_softirq(SCHEDULE_SOFTIRQ);会在每次do_softirq()之前执行.设置SCHEDULE_SOFTIRQ中断位

schedule()解析

见下一章节

工具

xen 3.4 代码分析

xen 3.0 代码分析

资源链接

说明

运行中的xen(schedule方面)

xen/include/xen/softirq.h

xen/include/asm-ia64/softirq.h

xen/include/asm-x86/softirq.h

schedule()