Messages in this thread Patch in this message | | | From | Rusty Russell <> | Subject | Re: [PATCH 2/3] stop_machine: simplify | Date | Tue, 8 Jul 2008 23:11:35 +1000 |
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On Tuesday 08 July 2008 21:44:40 Akinobu Mita wrote: > I found a small possible cleanup in this patch.
Well spotted! I think this cleanup is actually orthogonal to my patch, so best served as a separate patch, how's this?
=== Hotplug CPU: don't check cpu_online after take_cpu_down
Akinobu points out that if take_cpu_down() succeeds, the cpu must be offline (otherwise we're in deep trouble anyway.
Remove the cpu_online() check, and put a BUG_ON().
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: "Akinobu Mita" <akinobu.mita@gmail.com>
diff -r 805a2e5e68dd kernel/cpu.c --- a/kernel/cpu.c Tue Jul 08 23:04:48 2008 +1000 +++ b/kernel/cpu.c Tue Jul 08 23:07:43 2008 +1000 @@ -226,8 +226,7 @@ static int __ref _cpu_down(unsigned int set_cpus_allowed_ptr(current, &tmp); err = __stop_machine_run(take_cpu_down, &tcd_param, cpu); - - if (err || cpu_online(cpu)) { + if (err) { /* CPU didn't die: tell everyone. Can't complain. */ if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod, hcpu) == NOTIFY_BAD) @@ -235,6 +234,7 @@ static int __ref _cpu_down(unsigned int goto out_allowed; } + BUG_ON(cpu_online(cpu)); /* Wait for it to sleep (leaving idle task). */ while (!idle_cpu(cpu))
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