[PATCH] m32r: Fix local-timer event handling (2757a71c) · Commits · 戴 / test

There was a scheduling problem of the m32r SMP kernel; A process rarely stopped and gave no responding but the other process have been handled by the other CPU still lives, then if we did something in the other terminal or something like that, the stopped process came back to life and continued its operation... (ex. LMbench: lat_sig) In the m32r SMP kernel, a local-timer event is delivered by using an IPI(inter processor interrupts); LOCAL_TIMER_IPI. And a function smp_send_timer() is prepared to send the LOCAL_TIMER_IPI from the current CPU to the other CPUs. The funtion smp_send_timer() was placed and used in do_IRQ() in former times (before 2.6.10-rc3-mm1 kernel), however, it was unintentionally removed when arch/m32r/kernel/irq.c was modified to employ the generic hardirq framework (CONFIG_GENERIC_HARDIRQ) in my previous patch. [PATCH 2.6.10-rc3-mm1] m32r: Use generic hardirq framework http://www.ussg.iu.edu/hypermail/linux/kernel/0412.2/0358.html The following patch fixes the above problem. Signed-off-by:

Hitoshi Yamamoto <hitoshiy@isl.melco.co.jp> Signed-off-by:

Hirokazu Takata <takata@linux-m32r.org> Signed-off-by:

Andrew Morton <akpm@osdl.org> Signed-off-by:

Linus Torvalds <torvalds@osdl.org>

arch/m32r/kernel/time.c

+4 −9

Original line number	Diff line number	Diff line
		@@ -205,8 +205,7 @@ static long last_rtc_update = 0;
		* timer_interrupt() needs to keep up the real-time clock,
		* as well as call the "do_timer()" routine every clocktick
		*/
		static inline void
		do_timer_interrupt(int irq, void dev_id, struct pt_regs regs)
		irqreturn_t timer_interrupt(int irq, void dev_id, struct pt_regs regs)
		{
		#ifndef CONFIG_SMP
		profile_tick(CPU_PROFILING, regs);
		@@ -221,6 +220,7 @@ do_timer_interrupt(int irq, void dev_id, struct pt_regs regs)
		* CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
		* called as close as possible to 500 ms before the new second starts.
		*/
		write_seqlock(&xtime_lock);
		if ((time_status & STA_UNSYNC) == 0
		&& xtime.tv_sec > last_rtc_update + 660
		&& (xtime.tv_nsec / 1000) >= 500000 - ((unsigned)TICK_SIZE) / 2
		@@ -231,6 +231,7 @@ do_timer_interrupt(int irq, void dev_id, struct pt_regs regs)
		else /* do it again in 60 s */
		last_rtc_update = xtime.tv_sec - 600;
		}
		write_sequnlock(&xtime_lock);
		/* As we return to user mode fire off the other CPU schedulers..
		this is basically because we don't yet share IRQ's around.
		This message is rigged to be safe on the 386 - basically it's
		@@ -238,14 +239,8 @@ do_timer_interrupt(int irq, void dev_id, struct pt_regs regs)

		#ifdef CONFIG_SMP
		smp_local_timer_interrupt(regs);
		smp_send_timer();
		#endif
		}

		irqreturn_t timer_interrupt(int irq, void dev_id, struct pt_regs regs)
		{
		write_seqlock(&xtime_lock);
		do_timer_interrupt(irq, NULL, regs);
		write_sequnlock(&xtime_lock);

		return IRQ_HANDLED;
		}

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