Re: [RFC][PATCH 1/2] Show quicklist at meminfo

From: KOSAKI Motohiro
Date: Thu Aug 21 2008 - 21:06:18 EST


> > quicklist_total_size() is racy against cpu hotplug. That's OK for
> > /proc/meminfo purposes (occasional transient inaccuracy?), but will it
> > crash? Not in the current implementation of per_cpu() afaict, but it
> > might crash if we ever teach cpu hotunplug to free up the percpu
> > resources.
>
> First, Quicklist doesn't concern to cpu hotplug at all.
> it is another quicklist problem.
>
> Next, I think it doesn't cause crash. but I haven't any test.
> So, I'll test cpu hotplug/unplug testing today.
>
> I'll report result tommorow.

OK.
I ran cpu hotplug/unplug coutinuous workload over 12H.
then, system crash doesn't happend.

So, I believe my patch is cpu unplug safe.


test method
--------------------------------------------------------------
1. open 7 terminal and following script run on each console.

CPU=cpuXXX; while true; do echo 0 > /sys/devices/system/cpu/$CPU/online; echo 1 > /sys/devi
ces/system/cpu/$CPU/online;done

2. open another console, following command run.

watch -n 1 cat /proc/meminfo



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