Messages in this thread |  | | | Date | Fri, 13 Nov 2009 15:51:02 -0800 | | From | Andrew Morton <> | | Subject | Re: [PATCH] Allow memory hotplug and hibernation in the same kernel |
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On Fri, 13 Nov 2009 11:59:44 +0100 Andi Kleen <andi@firstfloor.org> wrote:
> Allow memory hotplug and hibernation in the same kernel > > Memory hotplug and hibernation was excluded in Kconfig. This is obviously > a problem for distribution kernels who want to support both in the same > image. > > After some discussions with Rafael and others the only problem is > with parallel memory hotadd or removal while a hibernation operation > is in process. It was also working for s390 before. > > This patch removes the Kconfig level exclusion, and simply > makes the memory add / remove functions grab the pm_mutex > to exclude against hibernation. > > ... > > +extern struct mutex pm_mutex;
Am a bit worried by the new mutex.
> #ifndef CONFIG_HIBERNATION > static inline void register_nosave_region(unsigned long b, unsigned long e) > { > @@ -308,8 +310,23 @@ static inline void register_nosave_regio > static inline void register_nosave_region_late(unsigned long b, unsigned long e) > { > } > -#endif > > -extern struct mutex pm_mutex; > +static inline void lock_hibernation(void) {} > +static inline void unlock_hibernation(void) {} > + > +#else > + > +/* Let some subsystems like memory hotadd exclude hibernation */ > + > +static inline void lock_hibernation(void) > +{ > + mutex_lock(&pm_mutex); > +} > + > +static inline void unlock_hibernation(void) > +{ > + mutex_unlock(&pm_mutex); > +} > +#endif
Has this been carefully reviewed and lockdep-tested to ensure that we didn't introduce any ab/ba nasties?
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