Commit 6ad696d2 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

mm: allow memory hotplug and hibernation in the same kernel 



Allow memory hotplug and hibernation in the same kernel

Memory hotplug and hibernation were exclusive 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.

Fixes a regression - old kernels didn't exclude memory hotadd and
hibernation.

Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 93981800

include/linux/suspend.h

+19 −2
Original line number Diff line number Diff line
@@ -301,6 +301,8 @@ static inline int unregister_pm_notifier(struct notifier_block *nb) 
#define pm_notifier(fn, pri)	do { (void)(fn); } while (0)

#endif /* !CONFIG_PM_SLEEP */



extern struct mutex pm_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_region(unsigned long b, unsigned long e) 
static inline void register_nosave_region_late(unsigned long b, unsigned long e)

{

}

#endif



extern struct mutex pm_mutex;

static inline void lock_system_sleep(void) {}

static inline void unlock_system_sleep(void) {}



#else



/* Let some subsystems like memory hotadd exclude hibernation */



static inline void lock_system_sleep(void)

{

	mutex_lock(&pm_mutex);

}



static inline void unlock_system_sleep(void)

{

	mutex_unlock(&pm_mutex);

}

#endif



#endif /* _LINUX_SUSPEND_H */

mm/Kconfig

+1 −4
Original line number Diff line number Diff line
@@ -128,12 +128,9 @@ config SPARSEMEM_VMEMMAP 
config MEMORY_HOTPLUG

	bool "Allow for memory hot-add"

	depends on SPARSEMEM || X86_64_ACPI_NUMA

	depends on HOTPLUG && !(HIBERNATION && !S390) && ARCH_ENABLE_MEMORY_HOTPLUG

	depends on HOTPLUG && ARCH_ENABLE_MEMORY_HOTPLUG

	depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390)



comment "Memory hotplug is currently incompatible with Software Suspend"

	depends on SPARSEMEM && HOTPLUG && HIBERNATION && !S390



config MEMORY_HOTPLUG_SPARSE

	def_bool y

	depends on SPARSEMEM && MEMORY_HOTPLUG

mm/memory_hotplug.c

+17 −4
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <linux/migrate.h>

#include <linux/page-isolation.h>

#include <linux/pfn.h>

#include <linux/suspend.h>



#include <asm/tlbflush.h>
@@ -485,14 +486,18 @@ int __ref add_memory(int nid, u64 start, u64 size) 
	struct resource *res;

	int ret;



	lock_system_sleep();



	res = register_memory_resource(start, size);

	ret = -EEXIST;

	if (!res)

		return -EEXIST;

		goto out;



	if (!node_online(nid)) {

		pgdat = hotadd_new_pgdat(nid, start);

		ret = -ENOMEM;

		if (!pgdat)

			return -ENOMEM;

			goto out;

		new_pgdat = 1;

	}
@@ -515,7 +520,8 @@ int __ref add_memory(int nid, u64 start, u64 size) 
		BUG_ON(ret);

	}



	return ret;

	goto out;



error:

	/* rollback pgdat allocation and others */

	if (new_pgdat)
@@ -523,6 +529,8 @@ error: 
	if (res)

		release_memory_resource(res);



out:

	unlock_system_sleep();

	return ret;

}

EXPORT_SYMBOL_GPL(add_memory);
@@ -759,6 +767,8 @@ int offline_pages(unsigned long start_pfn, 
	if (!test_pages_in_a_zone(start_pfn, end_pfn))

		return -EINVAL;



	lock_system_sleep();



	zone = page_zone(pfn_to_page(start_pfn));

	node = zone_to_nid(zone);

	nr_pages = end_pfn - start_pfn;
@@ -766,7 +776,7 @@ int offline_pages(unsigned long start_pfn, 
	/* set above range as isolated */

	ret = start_isolate_page_range(start_pfn, end_pfn);

	if (ret)

		return ret;

		goto out;



	arg.start_pfn = start_pfn;

	arg.nr_pages = nr_pages;
@@ -844,6 +854,7 @@ repeat: 
	writeback_set_ratelimit();



	memory_notify(MEM_OFFLINE, &arg);

	unlock_system_sleep();

	return 0;



failed_removal:
@@ -853,6 +864,8 @@ failed_removal: 
	/* pushback to free area */

	undo_isolate_page_range(start_pfn, end_pfn);



out:

	unlock_system_sleep();

	return ret;

}

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