[HMM v15 02/16] mm/memory/hotplug: convert device bool to int to allow for more flags v2

From: JÃrÃme Glisse
Date: Fri Jan 06 2017 - 10:46:14 EST

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When hotpluging memory we want more informations on the type of memory and
its properties. Replace the device boolean flag by an int and define a set
of flags.

New property for device memory is an opt-in flag to allow page migration
from and to a ZONE_DEVICE. Existing user of ZONE_DEVICE are not expecting
page migration to work for their pages. New changes to page migration i
changing that and we now need a flag to explicitly opt-in page migration.

Changes since v1:
- Improved commit message
- Improved define name
- Improved comments
- Typos

Signed-off-by: JÃrÃme Glisse <jglisse@xxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
---
arch/ia64/mm/init.c | 23 ++++++++++++++++++++---
arch/powerpc/mm/mem.c | 22 +++++++++++++++++++---
arch/s390/mm/init.c | 10 ++++++++--
arch/sh/mm/init.c | 22 +++++++++++++++++++---
arch/tile/mm/init.c | 10 ++++++++--
arch/x86/mm/init_32.c | 23 ++++++++++++++++++++---
arch/x86/mm/init_64.c | 23 ++++++++++++++++++++---
include/linux/memory_hotplug.h | 24 ++++++++++++++++++++++--
include/linux/memremap.h | 11 +++++++++++
kernel/memremap.c | 4 ++--
mm/memory_hotplug.c | 4 ++--
11 files changed, 151 insertions(+), 25 deletions(-)

diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 1841ef6..303027e 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -645,18 +645,27 @@ mem_init (void)
}

#ifdef CONFIG_MEMORY_HOTPLUG
-int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
+int arch_add_memory(int nid, u64 start, u64 size, int flags)
{
+ const int supported_flags = MEMORY_DEVICE |
+ MEMORY_DEVICE_ALLOW_MIGRATE;
pg_data_t *pgdat;
struct zone *zone;
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
int ret;

+ /* Each flag need special handling so error out on un-supported flag */
+ if (flags & (~supported_flags)) {
+ BUG();
+ return -EINVAL;
+ }
+
pgdat = NODE_DATA(nid);

zone = pgdat->node_zones +
- zone_for_memory(nid, start, size, ZONE_NORMAL, for_device);
+ zone_for_memory(nid, start, size, ZONE_NORMAL,
+ flags & MEMORY_DEVICE);
ret = __add_pages(nid, zone, start_pfn, nr_pages);

if (ret)
@@ -667,13 +676,21 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
}

#ifdef CONFIG_MEMORY_HOTREMOVE
-int arch_remove_memory(u64 start, u64 size)
+int arch_remove_memory(u64 start, u64 size, int flags)
{
+ const int supported_flags = MEMORY_DEVICE |
+ MEMORY_DEVICE_ALLOW_MIGRATE;
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
struct zone *zone;
int ret;

+ /* Each flag need special handling so error out on un-supported flag */
+ if (flags & (~supported_flags)) {
+ BUG();
+ return -EINVAL;
+ }
+
zone = page_zone(pfn_to_page(start_pfn));
ret = __remove_pages(zone, start_pfn, nr_pages);
if (ret)
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 5f84433..6e877d3 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -126,14 +126,22 @@ int __weak remove_section_mapping(unsigned long start, unsigned long end)
return -ENODEV;
}

-int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
+int arch_add_memory(int nid, u64 start, u64 size, int flags)
{
+ const int supported_flags = MEMORY_DEVICE |
+ MEMORY_DEVICE_ALLOW_MIGRATE;
struct pglist_data *pgdata;
struct zone *zone;
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
int rc;

+ /* Each flag need special handling so error out on un-supported flag */
+ if (flags & (~supported_flags)) {
+ BUG();
+ return -EINVAL;
+ }
+
pgdata = NODE_DATA(nid);

start = (unsigned long)__va(start);
@@ -147,19 +155,27 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device)

/* this should work for most non-highmem platforms */
zone = pgdata->node_zones +
- zone_for_memory(nid, start, size, 0, for_device);
+ zone_for_memory(nid, start, size, 0, flags & MEMORY_DEVICE);

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

#ifdef CONFIG_MEMORY_HOTREMOVE
-int arch_remove_memory(u64 start, u64 size)
+int arch_remove_memory(u64 start, u64 size, int flags)
{
+ const int supported_flags = MEMORY_DEVICE |
+ MEMORY_DEVICE_ALLOW_MIGRATE;
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
struct zone *zone;
int ret;

+ /* Each flag need special handling so error out on un-supported flag */
+ if (flags & (~supported_flags)) {
+ BUG();
+ return -EINVAL;
+ }
+
zone = page_zone(pfn_to_page(start_pfn));
ret = __remove_pages(zone, start_pfn, nr_pages);
if (ret)
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index b3e9d18..e94b9e1 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -149,7 +149,7 @@ void __init free_initrd_mem(unsigned long start, unsigned long end)
#endif

#ifdef CONFIG_MEMORY_HOTPLUG
-int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
+int arch_add_memory(int nid, u64 start, u64 size, int flags)
{
unsigned long zone_start_pfn, zone_end_pfn, nr_pages;
unsigned long start_pfn = PFN_DOWN(start);
@@ -158,6 +158,12 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
struct zone *zone;
int rc, i;

+ /* Each flag need special handling so error out on un-supported flag */
+ if (flags) {
+ BUG();
+ return -EINVAL;
+ }
+
rc = vmem_add_mapping(start, size);
if (rc)
return rc;
@@ -201,7 +207,7 @@ unsigned long memory_block_size_bytes(void)
}

#ifdef CONFIG_MEMORY_HOTREMOVE
-int arch_remove_memory(u64 start, u64 size)
+int arch_remove_memory(u64 start, u64 size, int flags)
{
/*
* There is no hardware or firmware interface which could trigger a
diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
index 7549186..0ca69ac 100644
--- a/arch/sh/mm/init.c
+++ b/arch/sh/mm/init.c
@@ -485,19 +485,27 @@ void free_initrd_mem(unsigned long start, unsigned long end)
#endif

#ifdef CONFIG_MEMORY_HOTPLUG
-int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
+int arch_add_memory(int nid, u64 start, u64 size, int flags)
{
+ const int supported_flags = MEMORY_DEVICE |
+ MEMORY_DEVICE_ALLOW_MIGRATE;
pg_data_t *pgdat;
unsigned long start_pfn = PFN_DOWN(start);
unsigned long nr_pages = size >> PAGE_SHIFT;
int ret;

+ /* Each flag need special handling so error out on un-supported flag */
+ if (flags & (~supported_flags)) {
+ BUG();
+ return -EINVAL;
+ }
+
pgdat = NODE_DATA(nid);

/* We only have ZONE_NORMAL, so this is easy.. */
ret = __add_pages(nid, pgdat->node_zones +
zone_for_memory(nid, start, size, ZONE_NORMAL,
- for_device),
+ flags & MEMORY_DEVICE),
start_pfn, nr_pages);
if (unlikely(ret))
printk("%s: Failed, __add_pages() == %d\n", __func__, ret);
@@ -516,13 +524,21 @@ EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
#endif

#ifdef CONFIG_MEMORY_HOTREMOVE
-int arch_remove_memory(u64 start, u64 size)
+int arch_remove_memory(u64 start, u64 size, int flags)
{
+ const int supported_flags = MEMORY_DEVICE |
+ MEMORY_DEVICE_ALLOW_MIGRATE;
unsigned long start_pfn = PFN_DOWN(start);
unsigned long nr_pages = size >> PAGE_SHIFT;
struct zone *zone;
int ret;

+ /* Each flag need special handling so error out on un-supported flag */
+ if (flags & (~supported_flags)) {
+ BUG();
+ return -EINVAL;
+ }
+
zone = page_zone(pfn_to_page(start_pfn));
ret = __remove_pages(zone, start_pfn, nr_pages);
if (unlikely(ret))
diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
index adce254..ba001b1 100644
--- a/arch/tile/mm/init.c
+++ b/arch/tile/mm/init.c
@@ -863,13 +863,19 @@ void __init mem_init(void)
* memory to the highmem for now.
*/
#ifndef CONFIG_NEED_MULTIPLE_NODES
-int arch_add_memory(u64 start, u64 size, bool for_device)
+int arch_add_memory(u64 start, u64 size, int flags)
{
struct pglist_data *pgdata = &contig_page_data;
struct zone *zone = pgdata->node_zones + MAX_NR_ZONES-1;
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;

+ /* Each flag need special handling so error out on un-supported flag */
+ if (flags) {
+ BUG();
+ return -EINVAL;
+ }
+
return __add_pages(zone, start_pfn, nr_pages);
}

@@ -879,7 +885,7 @@ int remove_memory(u64 start, u64 size)
}

#ifdef CONFIG_MEMORY_HOTREMOVE
-int arch_remove_memory(u64 start, u64 size)
+int arch_remove_memory(u64 start, u64 size, int flags)
{
/* TODO */
return -EBUSY;
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index cf80590..8287a4b 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -816,24 +816,41 @@ void __init mem_init(void)
}

#ifdef CONFIG_MEMORY_HOTPLUG
-int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
+int arch_add_memory(int nid, u64 start, u64 size, int flags)
{
+ const int supported_flags = MEMORY_DEVICE |
+ MEMORY_DEVICE_ALLOW_MIGRATE;
struct pglist_data *pgdata = NODE_DATA(nid);
struct zone *zone = pgdata->node_zones +
- zone_for_memory(nid, start, size, ZONE_HIGHMEM, for_device);
+ zone_for_memory(nid, start, size, ZONE_HIGHMEM,
+ flags & MEMORY_DEVICE);
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;

+ /* Each flag need special handling so error out on un-supported flag */
+ if (flags & (~supported_flags)) {
+ BUG();
+ return -EINVAL;
+ }
+
return __add_pages(nid, zone, start_pfn, nr_pages);
}

#ifdef CONFIG_MEMORY_HOTREMOVE
-int arch_remove_memory(u64 start, u64 size)
+int arch_remove_memory(u64 start, u64 size, int flags)
{
+ const int supported_flags = MEMORY_DEVICE |
+ MEMORY_DEVICE_ALLOW_MIGRATE;
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
struct zone *zone;

+ /* Each flag need special handling so error out on un-supported flag */
+ if (flags & (~supported_flags)) {
+ BUG();
+ return -EINVAL;
+ }
+
zone = page_zone(pfn_to_page(start_pfn));
return __remove_pages(zone, start_pfn, nr_pages);
}
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 14b9dd7..442ac86 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -651,15 +651,24 @@ static void update_end_of_memory_vars(u64 start, u64 size)
* Memory is added always to NORMAL zone. This means you will never get
* additional DMA/DMA32 memory.
*/
-int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
+int arch_add_memory(int nid, u64 start, u64 size, int flags)
{
+ const int supported_flags = MEMORY_DEVICE |
+ MEMORY_DEVICE_ALLOW_MIGRATE;
struct pglist_data *pgdat = NODE_DATA(nid);
struct zone *zone = pgdat->node_zones +
- zone_for_memory(nid, start, size, ZONE_NORMAL, for_device);
+ zone_for_memory(nid, start, size, ZONE_NORMAL,
+ flags & MEMORY_DEVICE);
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
int ret;

+ /* Each flag need special handling so error out on un-supported flag */
+ if (flags & (~supported_flags)) {
+ BUG();
+ return -EINVAL;
+ }
+
init_memory_mapping(start, start + size);

ret = __add_pages(nid, zone, start_pfn, nr_pages);
@@ -956,8 +965,10 @@ kernel_physical_mapping_remove(unsigned long start, unsigned long end)
remove_pagetable(start, end, true);
}

-int __ref arch_remove_memory(u64 start, u64 size)
+int __ref arch_remove_memory(u64 start, u64 size, int flags)
{
+ const int supported_flags = MEMORY_DEVICE |
+ MEMORY_DEVICE_ALLOW_MIGRATE;
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
struct page *page = pfn_to_page(start_pfn);
@@ -965,6 +976,12 @@ int __ref arch_remove_memory(u64 start, u64 size)
struct zone *zone;
int ret;

+ /* Each flag need special handling so error out on un-supported flag */
+ if (flags & (~supported_flags)) {
+ BUG();
+ return -EINVAL;
+ }
+
/* With altmap the first mapped page is offset from @start */
altmap = to_vmem_altmap((unsigned long) page);
if (altmap)
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 01033fa..3f50eb8 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -103,7 +103,7 @@ extern bool memhp_auto_online;

#ifdef CONFIG_MEMORY_HOTREMOVE
extern bool is_pageblock_removable_nolock(struct page *page);
-extern int arch_remove_memory(u64 start, u64 size);
+extern int arch_remove_memory(u64 start, u64 size, int flags);
extern int __remove_pages(struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages);
#endif /* CONFIG_MEMORY_HOTREMOVE */
@@ -275,7 +275,27 @@ extern int add_memory(int nid, u64 start, u64 size);
extern int add_memory_resource(int nid, struct resource *resource, bool online);
extern int zone_for_memory(int nid, u64 start, u64 size, int zone_default,
bool for_device);
-extern int arch_add_memory(int nid, u64 start, u64 size, bool for_device);
+
+/*
+ * When hotpluging memory with arch_add_memory() we want more informations on
+ * the type of memory and its properties. The flags parameter allow to provide
+ * more informations on the memory which is being addedd.
+ *
+ * Provide an opt-in flag for struct page migration. Persistent device memory
+ * never relied on struct page migration so far and new user of might also
+ * prefer avoiding struct page migration.
+ *
+ * New non device memory specific flags can be added if ever needed.
+ *
+ * MEMORY_REGULAR: regular system memory
+ * DEVICE_MEMORY: device memory create a ZONE_DEVICE zone for it
+ * DEVICE_MEMORY_ALLOW_MIGRATE: page in that device memory ca be migrated
+ */
+#define MEMORY_NORMAL 0
+#define MEMORY_DEVICE (1 << 0)
+#define MEMORY_DEVICE_ALLOW_MIGRATE (1 << 1)
+
+extern int arch_add_memory(int nid, u64 start, u64 size, int flags);
extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
extern bool is_memblock_offlined(struct memory_block *mem);
extern void remove_memory(int nid, u64 start, u64 size);
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 9341619..f7e0609 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -53,6 +53,12 @@ struct dev_pagemap {
void *devm_memremap_pages(struct device *dev, struct resource *res,
struct percpu_ref *ref, struct vmem_altmap *altmap);
struct dev_pagemap *find_dev_pagemap(resource_size_t phys);
+
+static inline bool dev_page_allow_migrate(const struct page *page)
+{
+ return ((page_zonenum(page) == ZONE_DEVICE) &&
+ (page->pgmap->flags & MEMORY_DEVICE_ALLOW_MIGRATE));
+}
#else
static inline void *devm_memremap_pages(struct device *dev,
struct resource *res, struct percpu_ref *ref,
@@ -71,6 +77,11 @@ static inline struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
{
return NULL;
}
+
+static inline bool dev_page_allow_migrate(const struct page *page)
+{
+ return false;
+}
#endif

/**
diff --git a/kernel/memremap.c b/kernel/memremap.c
index b501e39..07665eb 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -246,7 +246,7 @@ static void devm_memremap_pages_release(struct device *dev, void *data)
/* pages are dead and unused, undo the arch mapping */
align_start = res->start & ~(SECTION_SIZE - 1);
align_size = ALIGN(resource_size(res), SECTION_SIZE);
- arch_remove_memory(align_start, align_size);
+ arch_remove_memory(align_start, align_size, MEMORY_DEVICE);
untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
pgmap_radix_release(res);
dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc,
@@ -358,7 +358,7 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
if (error)
goto err_pfn_remap;

- error = arch_add_memory(nid, align_start, align_size, true);
+ error = arch_add_memory(nid, align_start, align_size, MEMORY_DEVICE);
if (error)
goto err_add_memory;

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e43142c1..096c651 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1372,7 +1372,7 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online)
}

/* call arch's memory hotadd */
- ret = arch_add_memory(nid, start, size, false);
+ ret = arch_add_memory(nid, start, size, MEMORY_NORMAL);

if (ret < 0)
goto error;
@@ -2156,7 +2156,7 @@ void __ref remove_memory(int nid, u64 start, u64 size)
memblock_free(start, size);
memblock_remove(start, size);

- arch_remove_memory(start, size);
+ arch_remove_memory(start, size, MEMORY_NORMAL);

try_offline_node(nid);

--
2.4.3

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