On Wed, 31 Aug 2016 08:55:49 +0530 Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx> wrote: > zone_names[] is used to identify any zone given it's index which > can be used in many other places. So moving the definition into > include/linux/mmzone.h for broader access. > > ... > > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -341,6 +341,23 @@ enum zone_type { > > }; > > +static char * const zone_names[__MAX_NR_ZONES] = { > +#ifdef CONFIG_ZONE_DMA > + "DMA", > +#endif > +#ifdef CONFIG_ZONE_DMA32 > + "DMA32", > +#endif > + "Normal", > +#ifdef CONFIG_HIGHMEM > + "HighMem", > +#endif > + "Movable", > +#ifdef CONFIG_ZONE_DEVICE > + "Device", > +#endif > +}; > + > #ifndef __GENERATING_BOUNDS_H > > struct zone { > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 3fbe73a..8e2261c 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -207,23 +207,6 @@ int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = { > > EXPORT_SYMBOL(totalram_pages); > > -static char * const zone_names[MAX_NR_ZONES] = { > -#ifdef CONFIG_ZONE_DMA > - "DMA", > -#endif > -#ifdef CONFIG_ZONE_DMA32 > - "DMA32", > -#endif > - "Normal", > -#ifdef CONFIG_HIGHMEM > - "HighMem", > -#endif > - "Movable", > -#ifdef CONFIG_ZONE_DEVICE > - "Device", > -#endif > -}; > - > char * const migratetype_names[MIGRATE_TYPES] = { > "Unmovable", > "Movable", This is worrisome. On some (ancient) compilers, this will produce a copy of that array into each compilation unit which includes mmzone.h. On smarter compilers, it will produce a copy of the array in each compilation unit which *uses* zone_names[]. On even smarter compilers (and linkers!), only one copy of zone_names[] will exist in vmlinux. I don't know if gcc is an "even smarter compiler" and I didn't check, and I didn't check which gcc versions are even smarter. I'd rather not have to ;) It is risky. So, let's just make it non-static and add a declaration into mmzone.h, please. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>