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Commit a99824f3 authored by Badari Pulavarty's avatar Badari Pulavarty Committed by Paul Mackerras
Browse files

[POWERPC] Add arch-specific walk_memory_remove() for 64-bit powerpc 



walk_memory_resource() verifies if there are holes in a given memory
range, by checking against /proc/iomem.  On x86/ia64 system memory is
represented in /proc/iomem.  On powerpc, we don't show system memory as
IO resource in /proc/iomem - instead it's maintained in
/proc/device-tree.

This provides a way for an architecture to provide its own
walk_memory_resource() function.  On powerpc, the memory region is
small (16MB), contiguous and non-overlapping.  So extra checking
against the device-tree is not needed.

Signed-off-by: default avatarBadari Pulavarty <pbadari@us.ibm.com>
Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 1482471d

arch/powerpc/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -272,6 +272,9 @@ config HOTPLUG_CPU 
config ARCH_ENABLE_MEMORY_HOTPLUG

	def_bool y



config ARCH_HAS_WALK_MEMORY

	def_bool y



config ARCH_ENABLE_MEMORY_HOTREMOVE

	def_bool y

arch/powerpc/mm/mem.c

+17 −0
Original line number Diff line number Diff line
@@ -145,6 +145,23 @@ int remove_memory(u64 start, u64 size) 
	return ret;

}

#endif /* CONFIG_MEMORY_HOTREMOVE */



/*

 * walk_memory_resource() needs to make sure there is no holes in a given

 * memory range. On PPC64, since this range comes from /sysfs, the range

 * is guaranteed to be valid, non-overlapping and can not contain any

 * holes. By the time we get here (memory add or remove), /proc/device-tree

 * is updated and correct. Only reason we need to check against device-tree

 * would be if we allow user-land to specify a memory range through a

 * system call/ioctl etc. instead of doing offline/online through /sysfs.

 */

int

walk_memory_resource(unsigned long start_pfn, unsigned long nr_pages, void *arg,

			int (*func)(unsigned long, unsigned long, void *))

{

	return  (*func)(start_pfn, nr_pages, arg);

}



#endif /* CONFIG_MEMORY_HOTPLUG */



void show_mem(void)

kernel/resource.c

+1 −1
Original line number Diff line number Diff line
@@ -228,7 +228,7 @@ int release_resource(struct resource *old) 


EXPORT_SYMBOL(release_resource);



#ifdef CONFIG_MEMORY_HOTPLUG

#if defined(CONFIG_MEMORY_HOTPLUG) && !defined(CONFIG_ARCH_HAS_WALK_MEMORY)

/*

 * Finds the lowest memory reosurce exists within [res->start.res->end)

 * the caller must specify res->start, res->end, res->flags.