From 1b862aecfbd419cdc4553645bf86d07554279bed Mon Sep 17 00:00:00 2001

From: Michal Hocko <mhocko@suse.com>

Date: Thu, 6 Jul 2017 15:37:45 -0700

Subject: [PATCH 04/16] mm, memory_hotplug: get rid of is_zone_device_section

Git-commit: 1b862aecfbd419cdc4553645bf86d07554279bed

Patch-mainline: 4.13-rc1

References: bnc#1027153, bnc#1030659, bnc#1047595, fate#323634

Device memory hotplug hooks into regular memory hotplug only half way.

It needs memory sections to track struct pages but there is no

need/desire to associate those sections with memory blocks and export

them to the userspace via sysfs because they cannot be onlined anyway.

This is currently expressed by for_device argument to arch_add_memory

which then makes sure to associate the given memory range with

ZONE_DEVICE.  register_new_memory then relies on is_zone_device_section

to distinguish special memory hotplug from the regular one.  While this

works now, later patches in this series want to move __add_zone outside

of arch_add_memory path so we have to come up with something else.

Add want_memblock down the __add_pages path and use it to control

whether the section->memblock association should be done.

arch_add_memory then just trivially want memblock for everything but

for_device hotplug.

remove_memory_section doesn't need is_zone_device_section either.  We

can simply skip all the memblock specific cleanup if there is no

memblock for the given section.

This shouldn't introduce any functional change.

Link: http://lkml.kernel.org/r/20170515085827.16474-5-mhocko@kernel.org

Signed-off-by: Michal Hocko <mhocko@suse.com>

Tested-by: Dan Williams <dan.j.williams@intel.com>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

Cc: Andi Kleen <ak@linux.intel.com>

Cc: Andrea Arcangeli <aarcange@redhat.com>

Cc: Balbir Singh <bsingharora@gmail.com>

Cc: Daniel Kiper <daniel.kiper@oracle.com>

Cc: David Rientjes <rientjes@google.com>

Cc: Heiko Carstens <heiko.carstens@de.ibm.com>

Cc: Igor Mammedov <imammedo@redhat.com>

Cc: Jerome Glisse <jglisse@redhat.com>

Cc: Joonsoo Kim <js1304@gmail.com>

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>

Cc: Mel Gorman <mgorman@suse.de>

Cc: Reza Arbab <arbab@linux.vnet.ibm.com>

Cc: Tobias Regnery <tobias.regnery@gmail.com>

Cc: Toshi Kani <toshi.kani@hpe.com>

Cc: Vitaly Kuznetsov <vkuznets@redhat.com>

Cc: Xishi Qiu <qiuxishi@huawei.com>

Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

---

 arch/ia64/mm/init.c            |  2 +-

 arch/powerpc/mm/mem.c          |  2 +-

 arch/s390/mm/init.c            |  2 +-

 arch/sh/mm/init.c              |  2 +-

 arch/x86/mm/init_32.c          |  2 +-

 arch/x86/mm/init_64.c          |  2 +-

 drivers/base/memory.c          | 23 +++++++++--------------

 include/linux/memory_hotplug.h |  2 +-

 mm/memory_hotplug.c            |  9 ++++++---

 9 files changed, 22 insertions(+), 24 deletions(-)

diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c

index 8f3efa682ee8..39e2aeb4669d 100644

--- a/arch/ia64/mm/init.c

+++ b/arch/ia64/mm/init.c

@@ -658,7 +658,7 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device)

 	zone = pgdat->node_zones +

 		zone_for_memory(nid, start, size, ZONE_NORMAL, for_device);

-	ret = __add_pages(nid, zone, start_pfn, nr_pages);

+	ret = __add_pages(nid, zone, start_pfn, nr_pages, !for_device);

 	if (ret)

 		printk("%s: Problem encountered in __add_pages() as ret=%d\n",

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c

index 9ee536ec0739..e6b2e6618b6c 100644

--- a/arch/powerpc/mm/mem.c

+++ b/arch/powerpc/mm/mem.c

@@ -151,7 +151,7 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device)

 	zone = pgdata->node_zones +

 		zone_for_memory(nid, start, size, 0, for_device);

-	return __add_pages(nid, zone, start_pfn, nr_pages);

+	return __add_pages(nid, zone, start_pfn, nr_pages, !for_device);

 }

 #ifdef CONFIG_MEMORY_HOTREMOVE

diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c

index 3348e60dd8ad..a3d549966b6a 100644

--- a/arch/s390/mm/init.c

+++ b/arch/s390/mm/init.c

@@ -195,7 +195,7 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device)

 			continue;

 		nr_pages = (start_pfn + size_pages > zone_end_pfn) ?

 			   zone_end_pfn - start_pfn : size_pages;

-		rc = __add_pages(nid, zone, start_pfn, nr_pages);

+		rc = __add_pages(nid, zone, start_pfn, nr_pages, !for_device);

 		if (rc)

 			break;

 		start_pfn += nr_pages;

diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c

index 75491862d900..a9d57f75ae8c 100644

--- a/arch/sh/mm/init.c

+++ b/arch/sh/mm/init.c

@@ -498,7 +498,7 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device)

 	ret = __add_pages(nid, pgdat->node_zones +

 			zone_for_memory(nid, start, size, ZONE_NORMAL,

 			for_device),

-			start_pfn, nr_pages);

+			start_pfn, nr_pages, !for_device);

 	if (unlikely(ret))

 		printk("%s: Failed, __add_pages() == %d\n", __func__, ret);

diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c

index 99fb83819a5f..94594b889144 100644

--- a/arch/x86/mm/init_32.c

+++ b/arch/x86/mm/init_32.c

@@ -831,7 +831,7 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device)

 	unsigned long start_pfn = start >> PAGE_SHIFT;

 	unsigned long nr_pages = size >> PAGE_SHIFT;

-	return __add_pages(nid, zone, start_pfn, nr_pages);

+	return __add_pages(nid, zone, start_pfn, nr_pages, !for_device);

 }

 #ifdef CONFIG_MEMORY_HOTREMOVE

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c

index dae6a5e5ad4a..9d64291459b6 100644

--- a/arch/x86/mm/init_64.c

+++ b/arch/x86/mm/init_64.c

@@ -787,7 +787,7 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device)

 	init_memory_mapping(start, start + size);

-	ret = __add_pages(nid, zone, start_pfn, nr_pages);

+	ret = __add_pages(nid, zone, start_pfn, nr_pages, !for_device);

 	WARN_ON_ONCE(ret);

 	/* update max_pfn, max_low_pfn and high_memory */

diff --git a/drivers/base/memory.c b/drivers/base/memory.c

index 90225ffee501..f8fd562c3f18 100644

--- a/drivers/base/memory.c

+++ b/drivers/base/memory.c

@@ -685,14 +685,6 @@ static int add_memory_block(int base_section_nr)

 	return 0;

 }

-static bool is_zone_device_section(struct mem_section *ms)

-{

-	struct page *page;

-

-	page = sparse_decode_mem_map(ms->section_mem_map, __section_nr(ms));

-	return is_zone_device_page(page);

-}

-

 /*

  * need an interface for the VM to add new memory regions,

  * but without onlining it.

@@ -702,9 +694,6 @@ int register_new_memory(int nid, struct mem_section *section)

 	int ret = 0;

 	struct memory_block *mem;

-	if (is_zone_device_section(section))

-		return 0;

-

 	mutex_lock(&mem_sysfs_mutex);

 	mem = find_memory_block(section);

@@ -741,11 +730,16 @@ static int remove_memory_section(unsigned long node_id,

 {

 	struct memory_block *mem;

-	if (is_zone_device_section(section))

-		return 0;

-

 	mutex_lock(&mem_sysfs_mutex);

+

+	/*

+	 * Some users of the memory hotplug do not want/need memblock to

+	 * track all sections. Skip over those.

+	 */

 	mem = find_memory_block(section);

+	if (!mem)

+		goto out_unlock;

+

 	unregister_mem_sect_under_nodes(mem, __section_nr(section));

 	mem->section_count--;

@@ -754,6 +748,7 @@ static int remove_memory_section(unsigned long node_id,

 	else

 		put_device(&mem->dev);

+out_unlock:

 	mutex_unlock(&mem_sysfs_mutex);

 	return 0;

 }

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h

index 134a2f69c21a..3c8cf86201c3 100644

--- a/include/linux/memory_hotplug.h

+++ b/include/linux/memory_hotplug.h

@@ -111,7 +111,7 @@ extern int __remove_pages(struct zone *zone, unsigned long start_pfn,

 /* reasonably generic interface to expand the physical pages in a zone  */

 extern int __add_pages(int nid, struct zone *zone, unsigned long start_pfn,

-	unsigned long nr_pages);

+	unsigned long nr_pages, bool want_memblock);

 #ifdef CONFIG_NUMA

 extern int memory_add_physaddr_to_nid(u64 start);

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c

index 6b6362819be2..c0147d3024eb 100644

--- a/mm/memory_hotplug.c

+++ b/mm/memory_hotplug.c

@@ -494,7 +494,7 @@ static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)

 }

 static int __meminit __add_section(int nid, struct zone *zone,

-					unsigned long phys_start_pfn)

+		unsigned long phys_start_pfn, bool want_memblock)

 {

 	int ret;

@@ -511,6 +511,9 @@ static int __meminit __add_section(int nid, struct zone *zone,

 	if (ret < 0)

 		return ret;

+	if (!want_memblock)

+		return 0;

+

 	return register_new_memory(nid, __pfn_to_section(phys_start_pfn));

 }

@@ -521,7 +524,7 @@ static int __meminit __add_section(int nid, struct zone *zone,

  * add the new pages.

  */

 int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,

-			unsigned long nr_pages)

+			unsigned long nr_pages, bool want_memblock)

 {

 	unsigned long i;

 	int err = 0;

@@ -549,7 +552,7 @@ int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,

 	}

 	for (i = start_sec; i <= end_sec; i++) {

-		err = __add_section(nid, zone, section_nr_to_pfn(i));

+		err = __add_section(nid, zone, section_nr_to_pfn(i), want_memblock);

 		/*

 		 * EEXIST is finally dealt with by ioresource collision

-- 

1.8.5.6