LinuxLists.cc - [PATCH v2 0/5] Allocate memmap from hotadded memory

2019-06-25 07:57:37

Subject: [PATCH v2 0/5] Allocate memmap from hotadded memory

Hi,

It has been while since I sent previous version [1].

In this version I added some feedback I got back then, like letting
the caller decide whether he wants allocating per memory block or
per memory range (patch#2), and having the chance to disable vmemmap when
users want to expose all hotpluggable memory to userspace (patch#5).

[Testing]

While I could test last version on powerpc, and Huawei's fellows helped me out
testing it on arm64, this time I could only test it on x86_64.
The codebase is quite the same, so I would not expect surprises.

- x86_64: small and large memblocks (128MB, 1G and 2G)
- Kernel module that adds memory spanning multiple memblocks
and remove that memory in a different granularity.

So far, only acpi memory hotplug uses the new flag.
The other callers can be changed depending on their needs.

Of course, more testing and feedback is appreciated.

[Coverletter]

This is another step to make memory hotplug more usable. The primary
goal of this patchset is to reduce memory overhead of the hot-added
memory (at least for SPARSEMEM_VMEMMAP memory model). The current way we use
to populate memmap (struct page array) has two main drawbacks:

a) it consumes an additional memory until the hotadded memory itself is
onlined and
b) memmap might end up on a different numa node which is especially true
for movable_node configuration.

a) it is a problem especially for memory hotplug based memory "ballooning"
solutions when the delay between physical memory hotplug and the
onlining can lead to OOM and that led to introduction of hacks like auto
onlining (see 31bc3858ea3e ("memory-hotplug: add automatic onlining
policy for the newly added memory")).

b) can have performance drawbacks.

Another minor case is that I have seen hot-add operations failing on archs
because they were running out of order-x pages.
E.g On powerpc, in certain configurations, we use order-8 pages,
and given 64KB base pagesize, that is 16MB.
If we run out of those, we just fail the operation and we cannot add
more memory.
We could fallback to base pages as x86_64 does, but we can do better.

One way to mitigate all these issues is to simply allocate memmap array
(which is the largest memory footprint of the physical memory hotplug)
from the hot-added memory itself. SPARSEMEM_VMEMMAP memory model allows
us to map any pfn range so the memory doesn't need to be online to be
usable for the array. See patch 3 for more details.
This feature is only usable when CONFIG_SPARSEMEM_VMEMMAP is set.

[Overall design]:

Implementation wise we reuse vmem_altmap infrastructure to override
the default allocator used by vmemap_populate. Once the memmap is
allocated we need a way to mark altmap pfns used for the allocation.
If MHP_MEMMAP_{DEVICE,MEMBLOCK} flag was passed, we set up the layout of the
altmap structure at the beginning of __add_pages(), and then we call
mark_vmemmap_pages().

The flags are either MHP_MEMMAP_DEVICE or MHP_MEMMAP_MEMBLOCK, and only differ
in the way they allocate vmemmap pages within the memory blocks.

MHP_MEMMAP_MEMBLOCK:
- With this flag, we will allocate vmemmap pages in each memory block.
This means that if we hot-add a range that spans multiple memory blocks,
we will use the beginning of each memory block for the vmemmap pages.
This strategy is good for cases where the caller wants the flexiblity
to hot-remove memory in a different granularity than when it was added.

MHP_MEMMAP_DEVICE:
- With this flag, we will store all vmemmap pages at the beginning of
hot-added memory.

So it is a tradeoff of flexiblity vs contigous memory.
More info on the above can be found in patch#2.

Depending on which flag is passed (MHP_MEMMAP_DEVICE or MHP_MEMMAP_MEMBLOCK),
mark_vmemmap_pages() gets called at a different stage.
With MHP_MEMMAP_MEMBLOCK, we call it once we have populated the sections
fitting in a single memblock, while with MHP_MEMMAP_DEVICE we wait until all
sections have been populated.

mark_vmemmap_pages() marks the pages as vmemmap and sets some metadata:

The current layout of the Vmemmap pages are:

[Head->refcount] : Nr sections used by this altmap
[Head->private] : Nr of vmemmap pages
[Tail->freelist] : Pointer to the head page

This is done to easy the computation we need in some places.
E.g:

Example 1)
We hot-add 1GB on x86_64 (memory block 128MB) using
MHP_MEMMAP_DEVICE:

head->_refcount = 8 sections
head->private = 4096 vmemmap pages
tail's->freelist = head

Example 2)
We hot-add 1GB on x86_64 using MHP_MEMMAP_MEMBLOCK:

[at the beginning of each memblock]
head->_refcount = 1 section
head->private = 512 vmemmap pages
tail's->freelist = head

We have the refcount because when using MHP_MEMMAP_DEVICE, we need to know
how much do we have to defer the call to vmemmap_free().
The thing is that the first pages of the hot-added range are used to create
the memmap mapping, so we cannot remove those first, otherwise we would blow up
when accessing the other pages.

What we do is that since when we hot-remove a memory-range, sections are being
removed sequentially, we wait until we hit the last section, and then we free
the hole range to vmemmap_free backwards.
We know that it is the last section because in every pass we
decrease head->_refcount, and when it reaches 0, we got our last section.

We also have to be careful about those pages during online and offline
operations. They are simply skipped, so online will keep them
reserved and so unusable for any other purpose and offline ignores them
so they do not block the offline operation.

One thing worth mention is that vmemmap pages residing in movable memory is not a
show-stopper for that memory to be offlined/migrated away.
Vmemmap pages are just ignored in that case and they stick around until sections
referred by those vmemmap pages are hot-removed.

[1] https://patchwork.kernel.org/cover/10875017/

Oscar Salvador (5):
drivers/base/memory: Remove unneeded check in
remove_memory_block_devices
mm,memory_hotplug: Introduce MHP_VMEMMAP_FLAGS
mm,memory_hotplug: Introduce Vmemmap page helpers
mm,memory_hotplug: allocate memmap from the added memory range for
sparse-vmemmap
mm,memory_hotplug: Allow userspace to enable/disable vmemmap

arch/arm64/mm/mmu.c | 5 +-
arch/powerpc/mm/init_64.c | 7 ++
arch/s390/mm/init.c | 6 ++
arch/x86/mm/init_64.c | 10 +++
drivers/acpi/acpi_memhotplug.c | 2 +-
drivers/base/memory.c | 41 +++++++++--
drivers/dax/kmem.c | 2 +-
drivers/hv/hv_balloon.c | 2 +-
drivers/s390/char/sclp_cmd.c | 2 +-
drivers/xen/balloon.c | 2 +-
include/linux/memory_hotplug.h | 31 ++++++++-
include/linux/memremap.h | 2 +-
include/linux/page-flags.h | 34 +++++++++
mm/compaction.c | 7 ++
mm/memory_hotplug.c | 152 ++++++++++++++++++++++++++++++++++-------
mm/page_alloc.c | 22 +++++-
mm/page_isolation.c | 14 +++-
mm/sparse.c | 93 +++++++++++++++++++++++++
mm/util.c | 2 +
19 files changed, 394 insertions(+), 42 deletions(-)

--
2.12.3

2019-06-25 07:58:14

by Oscar Salvador

[permalink] [raw]

Subject: [PATCH v2 2/5] mm,memory_hotplug: Introduce MHP_VMEMMAP_FLAGS

This patch introduces MHP_MEMMAP_DEVICE and MHP_MEMMAP_MEMBLOCK flags,
and prepares the callers that add memory to take a "flags" parameter.
This "flags" parameter will be evaluated later on in Patch#3
to init mhp_restrictions struct.

The callers are:

add_memory
__add_memory
add_memory_resource

Unfortunately, we do not have a single entry point to add memory, as depending
on the requisites of the caller, they want to hook up in different places,
(e.g: Xen reserve_additional_memory()), so we have to spread the parameter
in the three callers.

The flags are either MHP_MEMMAP_DEVICE or MHP_MEMMAP_MEMBLOCK, and only differ
in the way they allocate vmemmap pages within the memory blocks.

MHP_MEMMAP_MEMBLOCK:
- With this flag, we will allocate vmemmap pages in each memory block.
This means that if we hot-add a range that spans multiple memory blocks,
we will use the beginning of each memory block for the vmemmap pages.
This strategy is good for cases where the caller wants the flexiblity
to hot-remove memory in a different granularity than when it was added.

E.g:
We allocate a range (x,y], that spans 3 memory blocks, and given
memory block size = 128MB.
[memblock#0 ]
[0 - 511 pfns ] - vmemmaps for section#0
[512 - 32767 pfns ] - normal memory

[memblock#1 ]
[32768 - 33279 pfns] - vmemmaps for section#1
[33280 - 65535 pfns] - normal memory

[memblock#2 ]
[65536 - 66047 pfns] - vmemmap for section#2
[66048 - 98304 pfns] - normal memory

MHP_MEMMAP_DEVICE:
- With this flag, we will store all vmemmap pages at the beginning of
hot-added memory.

E.g:
We allocate a range (x,y], that spans 3 memory blocks, and given
memory block size = 128MB.
[memblock #0 ]
[0 - 1533 pfns ] - vmemmap for section#{0-2}
[1534 - 98304 pfns] - normal memory

When using larger memory blocks (1GB or 2GB), the principle is the same.

Of course, MHP_MEMMAP_DEVICE is nicer when it comes to have a large contigous
area, while MHP_MEMMAP_MEMBLOCK allows us to have flexibility when removing the
memory.

Signed-off-by: Oscar Salvador <[email protected]>
---
drivers/acpi/acpi_memhotplug.c | 2 +-
drivers/base/memory.c | 2 +-
drivers/dax/kmem.c | 2 +-
drivers/hv/hv_balloon.c | 2 +-
drivers/s390/char/sclp_cmd.c | 2 +-
drivers/xen/balloon.c | 2 +-
include/linux/memory_hotplug.h | 22 +++++++++++++++++++---
mm/memory_hotplug.c | 10 +++++-----
8 files changed, 30 insertions(+), 14 deletions(-)

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index db013dc21c02..860f84e82dd0 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -218,7 +218,7 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
if (node < 0)
node = memory_add_physaddr_to_nid(info->start_addr);

- result = __add_memory(node, info->start_addr, info->length);
+ result = __add_memory(node, info->start_addr, info->length, 0);

/*
* If the memory block has been used by the kernel, add_memory()
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 07ba731beb42..ad9834b8b7f7 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -516,7 +516,7 @@ static ssize_t probe_store(struct device *dev, struct device_attribute *attr,

nid = memory_add_physaddr_to_nid(phys_addr);
ret = __add_memory(nid, phys_addr,
- MIN_MEMORY_BLOCK_SIZE * sections_per_block);
+ MIN_MEMORY_BLOCK_SIZE * sections_per_block, 0);

if (ret)
goto out;
diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index 3d0a7e702c94..e159184e0ba0 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -65,7 +65,7 @@ int dev_dax_kmem_probe(struct device *dev)
new_res->flags = IORESOURCE_SYSTEM_RAM;
new_res->name = dev_name(dev);

- rc = add_memory(numa_node, new_res->start, resource_size(new_res));
+ rc = add_memory(numa_node, new_res->start, resource_size(new_res), 0);
if (rc) {
release_resource(new_res);
kfree(new_res);
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 6fb4ea5f0304..beb92bc56186 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -731,7 +731,7 @@ static void hv_mem_hot_add(unsigned long start, unsigned long size,

nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn));
ret = add_memory(nid, PFN_PHYS((start_pfn)),
- (HA_CHUNK << PAGE_SHIFT));
+ (HA_CHUNK << PAGE_SHIFT), 0);

if (ret) {
pr_err("hot_add memory failed error is %d\n", ret);
diff --git a/drivers/s390/char/sclp_cmd.c b/drivers/s390/char/sclp_cmd.c
index 37d42de06079..f61026c7db7e 100644
--- a/drivers/s390/char/sclp_cmd.c
+++ b/drivers/s390/char/sclp_cmd.c
@@ -406,7 +406,7 @@ static void __init add_memory_merged(u16 rn)
if (!size)
goto skip_add;
for (addr = start; addr < start + size; addr += block_size)
- add_memory(numa_pfn_to_nid(PFN_DOWN(addr)), addr, block_size);
+ add_memory(numa_pfn_to_nid(PFN_DOWN(addr)), addr, block_size, 0);
skip_add:
first_rn = rn;
num = 1;
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 37a36c6b9f93..33814b3513ca 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -349,7 +349,7 @@ static enum bp_state reserve_additional_memory(void)
mutex_unlock(&balloon_mutex);
/* add_memory_resource() requires the device_hotplug lock */
lock_device_hotplug();
- rc = add_memory_resource(nid, resource);
+ rc = add_memory_resource(nid, resource, 0);
unlock_device_hotplug();
mutex_lock(&balloon_mutex);

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 0b8a5e5ef2da..6fdbce9d04f9 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -54,6 +54,22 @@ enum {
};

/*
+ * We want memmap (struct page array) to be allocated from the hotadded range.
+ * To do so, there are two possible ways depending on what the caller wants.
+ * 1) Allocate memmap pages per device (whole hot-added range)
+ * 2) Allocate memmap pages per memblock
+ * The former implies that we wil use the beginning of the hot-added range
+ * to store the memmap pages of the whole range, while the latter implies
+ * that we will use the beginning of each memblock to store its own memmap
+ * pages.
+ * Please note that only SPARSE_VMEMMAP implements this feature and some
+ * architectures might not support it even for that memory model (e.g. s390)
+ */
+#define MHP_MEMMAP_DEVICE (1UL<<0)
+#define MHP_MEMMAP_MEMBLOCK (1UL<<1)
+#define MHP_VMEMMAP_FLAGS (MHP_MEMMAP_DEVICE|MHP_MEMMAP_MEMBLOCK)
+
+/*
* Restrictions for the memory hotplug:
* flags: MHP_ flags
* altmap: alternative allocator for memmap array
@@ -342,9 +358,9 @@ static inline void __remove_memory(int nid, u64 start, u64 size) {}
extern void __ref free_area_init_core_hotplug(int nid);
extern int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
void *arg, int (*func)(struct memory_block *, void *));
-extern int __add_memory(int nid, u64 start, u64 size);
-extern int add_memory(int nid, u64 start, u64 size);
-extern int add_memory_resource(int nid, struct resource *resource);
+extern int __add_memory(int nid, u64 start, u64 size, unsigned long flags);
+extern int add_memory(int nid, u64 start, u64 size, unsigned long flags);
+extern int add_memory_resource(int nid, struct resource *resource, unsigned long flags);
extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages, struct vmem_altmap *altmap);
extern bool is_memblock_offlined(struct memory_block *mem);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 4e8e65954f31..e4e3baa6eaa7 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1057,7 +1057,7 @@ static int online_memory_block(struct memory_block *mem, void *arg)
*
* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
*/
-int __ref add_memory_resource(int nid, struct resource *res)
+int __ref add_memory_resource(int nid, struct resource *res, unsigned long flags)
{
struct mhp_restrictions restrictions = {};
u64 start, size;
@@ -1135,7 +1135,7 @@ int __ref add_memory_resource(int nid, struct resource *res)
}

/* requires device_hotplug_lock, see add_memory_resource() */
-int __ref __add_memory(int nid, u64 start, u64 size)
+int __ref __add_memory(int nid, u64 start, u64 size, unsigned long flags)
{
struct resource *res;
int ret;
@@ -1144,18 +1144,18 @@ int __ref __add_memory(int nid, u64 start, u64 size)
if (IS_ERR(res))
return PTR_ERR(res);

- ret = add_memory_resource(nid, res);
+ ret = add_memory_resource(nid, res, flags);
if (ret < 0)
release_memory_resource(res);
return ret;
}

-int add_memory(int nid, u64 start, u64 size)
+int add_memory(int nid, u64 start, u64 size, unsigned long flags)
{
int rc;

lock_device_hotplug();
- rc = __add_memory(nid, start, size);
+ rc = __add_memory(nid, start, size, flags);
unlock_device_hotplug();

return rc;
--
2.12.3

2019-06-25 07:58:20

by Oscar Salvador

[permalink] [raw]

Subject: [PATCH v2 3/5] mm,memory_hotplug: Introduce Vmemmap page helpers

Introduce a set of functions for Vmemmap pages.
Set of functions:

- {Set,Clear,Check} Vmemmap flag
- Given a vmemmap page, get its vmemmap-head
- Get #nr of vmemmap pages taking into account the current position
of the page

These functions will be used for the code handling Vmemmap pages.

Signed-off-by: Oscar Salvador <[email protected]>
---
include/linux/page-flags.h | 34 ++++++++++++++++++++++++++++++++++
mm/util.c | 2 ++
2 files changed, 36 insertions(+)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index b848517da64c..a8b9b57162b3 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -466,6 +466,40 @@ static __always_inline int __PageMovable(struct page *page)
PAGE_MAPPING_MOVABLE;
}

+#define VMEMMAP_PAGE (~PAGE_MAPPING_FLAGS)
+static __always_inline int PageVmemmap(struct page *page)
+{
+ return PageReserved(page) && (unsigned long)page->mapping == VMEMMAP_PAGE;
+}
+
+static __always_inline int __PageVmemmap(struct page *page)
+{
+ return (unsigned long)page->mapping == VMEMMAP_PAGE;
+}
+
+static __always_inline void __ClearPageVmemmap(struct page *page)
+{
+ __ClearPageReserved(page);
+ page->mapping = NULL;
+}
+
+static __always_inline void __SetPageVmemmap(struct page *page)
+{
+ __SetPageReserved(page);
+ page->mapping = (void *)VMEMMAP_PAGE;
+}
+
+static __always_inline struct page *vmemmap_get_head(struct page *page)
+{
+ return (struct page *)page->freelist;
+}
+
+static __always_inline unsigned long get_nr_vmemmap_pages(struct page *page)
+{
+ struct page *head = vmemmap_get_head(page);
+ return head->private - (page - head);
+}
+
#ifdef CONFIG_KSM
/*
* A KSM page is one of those write-protected "shared pages" or "merged pages"
diff --git a/mm/util.c b/mm/util.c
index 021648a8a3a3..5e20563cdef6 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -607,6 +607,8 @@ struct address_space *page_mapping(struct page *page)
mapping = page->mapping;
if ((unsigned long)mapping & PAGE_MAPPING_ANON)
return NULL;
+ if ((unsigned long)mapping == VMEMMAP_PAGE)
+ return NULL;

return (void *)((unsigned long)mapping & ~PAGE_MAPPING_FLAGS);
}
--
2.12.3

2019-06-25 07:58:32

by Oscar Salvador

[permalink] [raw]

Subject: [PATCH v2 4/5] mm,memory_hotplug: allocate memmap from the added memory range for sparse-vmemmap

Physical memory hotadd has to allocate a memmap (struct page array) for
the newly added memory section. Currently, alloc_pages_node() is used
for those allocations.

This has some disadvantages:
a) an existing memory is consumed for that purpose
(~2MB per 128MB memory section on x86_64)
b) if the whole node is movable then we have off-node struct pages
which has performance drawbacks.

a) has turned out to be a problem for memory hotplug based ballooning
because the userspace might not react in time to online memory while
the memory consumed during physical hotadd consumes enough memory to
push system to OOM. 31bc3858ea3e ("memory-hotplug: add automatic onlining
policy for the newly added memory") has been added to workaround that
problem.

I have also seen hot-add operations failing on powerpc due to the fact
that we try to use order-8 pages. If the base page size is 64KB, this
gives us 16MB, and if we run out of those, we simply fail.
One could arge that we can fall back to basepages as we do in x86_64, but
we can do better when CONFIG_SPARSEMEM_VMEMMAP is enabled.

Vmemap page tables can map arbitrary memory.
That means that we can simply use the beginning of each memory section and
map struct pages there.
struct pages which back the allocated space then just need to be treated
carefully.

Implementation wise we reuse vmem_altmap infrastructure to override
the default allocator used by __vmemap_populate. Once the memmap is
allocated we need a way to mark altmap pfns used for the allocation.
If MHP_MEMMAP_{DEVICE,MEMBLOCK} flag was passed, we set up the layout of the
altmap structure at the beginning of __add_pages(), and then we call
mark_vmemmap_pages().

Depending on which flag is passed (MHP_MEMMAP_DEVICE or MHP_MEMMAP_MEMBLOCK),
mark_vmemmap_pages() gets called at a different stage.
With MHP_MEMMAP_MEMBLOCK, we call it once we have populated the sections
fitting in a single memblock, while with MHP_MEMMAP_DEVICE we wait until all
sections have been populated.

mark_vmemmap_pages() marks the pages as vmemmap and sets some metadata:

The current layout of the Vmemmap pages are:

[Head->refcount] : Nr sections used by this altmap
[Head->private] : Nr of vmemmap pages
[Tail->freelist] : Pointer to the head page

This is done to easy the computation we need in some places.
E.g:

Example 1)
We hot-add 1GB on x86_64 (memory block 128MB) using
MHP_MEMMAP_DEVICE:

head->_refcount = 8 sections
head->private = 4096 vmemmap pages
tail's->freelist = head

Example 2)
We hot-add 1GB on x86_64 using MHP_MEMMAP_MEMBLOCK:

[at the beginning of each memblock]
head->_refcount = 1 section
head->private = 512 vmemmap pages
tail's->freelist = head

We have the refcount because when using MHP_MEMMAP_DEVICE, we need to know
how much do we have to defer the call to vmemmap_free().
The thing is that the first pages of the hot-added range are used to create
the memmap mapping, so we cannot remove those first, otherwise we would blow up
when accessing the other pages.

What we do is that since when we hot-remove a memory-range, sections are being
removed sequentially, we wait until we hit the last section, and then we free
the hole range to vmemmap_free backwards.
We know that it is the last section because in every pass we
decrease head->_refcount, and when it reaches 0, we got our last section.

We also have to be careful about those pages during online and offline
operations. They are simply skipped, so online will keep them
reserved and so unusable for any other purpose and offline ignores them
so they do not block the offline operation.

In offline operation we only have to check for one particularity.
Depending on how large was the hot-added range, and using MHP_MEMMAP_DEVICE,
can be that one or more than one memory block is filled with only vmemmap pages.
We just need to check for this case and skip 1) isolating 2) migrating,
because those pages do not need to be migrated anywhere, they are self-hosted.

Signed-off-by: Oscar Salvador <[email protected]>
---
arch/arm64/mm/mmu.c | 5 +-
arch/powerpc/mm/init_64.c | 7 +++
arch/s390/mm/init.c | 6 ++
arch/x86/mm/init_64.c | 10 +++
drivers/acpi/acpi_memhotplug.c | 2 +-
drivers/base/memory.c | 2 +-
include/linux/memory_hotplug.h | 6 ++
include/linux/memremap.h | 2 +-
mm/compaction.c | 7 +++
mm/memory_hotplug.c | 138 +++++++++++++++++++++++++++++++++++------
mm/page_alloc.c | 22 ++++++-
mm/page_isolation.c | 14 ++++-
mm/sparse.c | 93 +++++++++++++++++++++++++++
13 files changed, 289 insertions(+), 25 deletions(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 93ed0df4df79..d4b5661fa6b6 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -765,7 +765,10 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
if (pmd_none(READ_ONCE(*pmdp))) {
void *p = NULL;

- p = vmemmap_alloc_block_buf(PMD_SIZE, node);
+ if (altmap)
+ p = altmap_alloc_block_buf(PMD_SIZE, altmap);
+ else
+ p = vmemmap_alloc_block_buf(PMD_SIZE, node);
if (!p)
return -ENOMEM;

diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index a4e17a979e45..ff9d2c245321 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -289,6 +289,13 @@ void __ref vmemmap_free(unsigned long start, unsigned long end,

if (base_pfn >= alt_start && base_pfn < alt_end) {
vmem_altmap_free(altmap, nr_pages);
+ } else if (PageVmemmap(page)) {
+ /*
+ * runtime vmemmap pages are residing inside the memory
+ * section so they do not have to be freed anywhere.
+ */
+ while (PageVmemmap(page))
+ __ClearPageVmemmap(page++);
} else if (PageReserved(page)) {
/* allocated from bootmem */
if (page_size < PAGE_SIZE) {
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index ffb81fe95c77..c045411552a3 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -226,6 +226,12 @@ int arch_add_memory(int nid, u64 start, u64 size,
unsigned long size_pages = PFN_DOWN(size);
int rc;

+ /*
+ * Physical memory is added only later during the memory online so we
+ * cannot use the added range at this stage unfortunately.
+ */
+ restrictions->flags &= ~restrictions->flags;
+
if (WARN_ON_ONCE(restrictions->altmap))
return -EINVAL;

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 688fb0687e55..00d17b666337 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -874,6 +874,16 @@ static void __meminit free_pagetable(struct page *page, int order)
unsigned long magic;
unsigned int nr_pages = 1 << order;

+ /*
+ * Runtime vmemmap pages are residing inside the memory section so
+ * they do not have to be freed anywhere.
+ */
+ if (PageVmemmap(page)) {
+ while (nr_pages--)
+ __ClearPageVmemmap(page++);
+ return;
+ }
+
/* bootmem page has reserved flag */
if (PageReserved(page)) {
__ClearPageReserved(page);
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 860f84e82dd0..3257edb98d90 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -218,7 +218,7 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
if (node < 0)
node = memory_add_physaddr_to_nid(info->start_addr);

- result = __add_memory(node, info->start_addr, info->length, 0);
+ result = __add_memory(node, info->start_addr, info->length, MHP_MEMMAP_DEVICE);

/*
* If the memory block has been used by the kernel, add_memory()
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index ad9834b8b7f7..e0ac9a3b66f8 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -32,7 +32,7 @@ static DEFINE_MUTEX(mem_sysfs_mutex);

#define to_memory_block(dev) container_of(dev, struct memory_block, dev)

-static int sections_per_block;
+int sections_per_block;

static inline int base_memory_block_id(int section_nr)
{
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 6fdbce9d04f9..e28e226c9a20 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -375,4 +375,10 @@ extern bool allow_online_pfn_range(int nid, unsigned long pfn, unsigned long nr_
int online_type);
extern struct zone *zone_for_pfn_range(int online_type, int nid, unsigned start_pfn,
unsigned long nr_pages);
+
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+extern void mark_vmemmap_pages(struct vmem_altmap *self);
+#else
+static inline void mark_vmemmap_pages(struct vmem_altmap *self) {}
+#endif
#endif /* __LINUX_MEMORY_HOTPLUG_H */
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 1732dea030b2..6de37e168f57 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -16,7 +16,7 @@ struct device;
* @alloc: track pages consumed, private to vmemmap_populate()
*/
struct vmem_altmap {
- const unsigned long base_pfn;
+ unsigned long base_pfn;
const unsigned long reserve;
unsigned long free;
unsigned long align;
diff --git a/mm/compaction.c b/mm/compaction.c
index 9e1b9acb116b..40697f74b8b4 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -855,6 +855,13 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
nr_scanned++;

page = pfn_to_page(low_pfn);
+ /*
+ * Vmemmap pages do not need to be isolated.
+ */
+ if (PageVmemmap(page)) {
+ low_pfn += get_nr_vmemmap_pages(page) - 1;
+ continue;
+ }

/*
* Check if the pageblock has already been marked skipped.
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e4e3baa6eaa7..b5106cb75795 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -42,6 +42,8 @@
#include "internal.h"
#include "shuffle.h"

+extern int sections_per_block;
+
/*
* online_page_callback contains pointer to current page onlining function.
* Initially it is generic_online_page(). If it is required it could be
@@ -279,6 +281,24 @@ static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
return 0;
}

+static void mhp_reset_altmap(unsigned long next_pfn,
+ struct vmem_altmap *altmap)
+{
+ altmap->base_pfn = next_pfn;
+ altmap->alloc = 0;
+}
+
+static void mhp_init_altmap(unsigned long pfn, unsigned long nr_pages,
+ unsigned long mhp_flags,
+ struct vmem_altmap *altmap)
+{
+ if (mhp_flags & MHP_MEMMAP_DEVICE)
+ altmap->free = nr_pages;
+ else
+ altmap->free = PAGES_PER_SECTION * sections_per_block;
+ altmap->base_pfn = pfn;
+}
+
/*
* Reasonably generic function for adding memory. It is
* expected that archs that support memory hotplug will
@@ -290,8 +310,17 @@ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
{
unsigned long i;
int start_sec, end_sec, err;
- struct vmem_altmap *altmap = restrictions->altmap;
+ struct vmem_altmap *altmap;
+ struct vmem_altmap __memblk_altmap = {};
+ unsigned long mhp_flags = restrictions->flags;
+ unsigned long sections_added;
+
+ if (mhp_flags & MHP_VMEMMAP_FLAGS) {
+ mhp_init_altmap(pfn, nr_pages, mhp_flags, &__memblk_altmap);
+ restrictions->altmap = &__memblk_altmap;
+ }

+ altmap = restrictions->altmap;
if (altmap) {
/*
* Validate altmap is within bounds of the total request
@@ -308,9 +337,10 @@ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
if (err)
return err;

+ sections_added = 1;
start_sec = pfn_to_section_nr(pfn);
end_sec = pfn_to_section_nr(pfn + nr_pages - 1);
- for (i = start_sec; i <= end_sec; i++) {
+ for (i = start_sec; i <= end_sec; i++, sections_added++) {
unsigned long pfns;

pfns = min(nr_pages, PAGES_PER_SECTION
@@ -320,9 +350,19 @@ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
break;
pfn += pfns;
nr_pages -= pfns;
+
+ if (mhp_flags & MHP_MEMMAP_MEMBLOCK &&
+ !(sections_added % sections_per_block)) {
+ mark_vmemmap_pages(altmap);
+ mhp_reset_altmap(pfn, altmap);
+ }
cond_resched();
}
vmemmap_populate_print_last();
+
+ if (mhp_flags & MHP_MEMMAP_DEVICE)
+ mark_vmemmap_pages(altmap);
+
return err;
}

@@ -642,6 +682,14 @@ static int online_pages_blocks(unsigned long start, unsigned long nr_pages)
while (start < end) {
order = min(MAX_ORDER - 1,
get_order(PFN_PHYS(end) - PFN_PHYS(start)));
+ /*
+ * Check if the pfn is aligned to its order.
+ * If not, we decrement the order until it is,
+ * otherwise __free_one_page will bug us.
+ */
+ while (start & ((1 << order) - 1))
+ order--;
+
(*online_page_callback)(pfn_to_page(start), order);

onlined_pages += (1UL << order);
@@ -654,13 +702,30 @@ static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
void *arg)
{
unsigned long onlined_pages = *(unsigned long *)arg;
+ unsigned long pfn = start_pfn;
+ unsigned long nr_vmemmap_pages = 0;

- if (PageReserved(pfn_to_page(start_pfn)))
- onlined_pages += online_pages_blocks(start_pfn, nr_pages);
+ if (PageVmemmap(pfn_to_page(pfn))) {
+ /*
+ * Do not send vmemmap pages to the page allocator.
+ */
+ nr_vmemmap_pages = get_nr_vmemmap_pages(pfn_to_page(start_pfn));
+ nr_vmemmap_pages = min(nr_vmemmap_pages, nr_pages);
+ pfn += nr_vmemmap_pages;
+ if (nr_vmemmap_pages == nr_pages)
+ /*
+ * If the entire range contains only vmemmap pages,
+ * there are no pages left for the page allocator.
+ */
+ goto skip_online;
+ }

+ if (PageReserved(pfn_to_page(pfn)))
+ onlined_pages += online_pages_blocks(pfn, nr_pages - nr_vmemmap_pages);
+skip_online:
online_mem_sections(start_pfn, start_pfn + nr_pages);

- *(unsigned long *)arg = onlined_pages;
+ *(unsigned long *)arg = onlined_pages + nr_vmemmap_pages;
return 0;
}

@@ -1051,6 +1116,23 @@ static int online_memory_block(struct memory_block *mem, void *arg)
return device_online(&mem->dev);
}

+static bool mhp_check_correct_flags(unsigned long flags)
+{
+ if (flags & MHP_VMEMMAP_FLAGS) {
+ if (!IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) {
+ WARN(1, "Vmemmap capability can only be used on"
+ "CONFIG_SPARSEMEM_VMEMMAP. Ignoring flags.\n");
+ return false;
+ }
+ if ((flags & MHP_VMEMMAP_FLAGS) == MHP_VMEMMAP_FLAGS) {
+ WARN(1, "Both MHP_MEMMAP_DEVICE and MHP_MEMMAP_MEMBLOCK"
+ "were passed. Ignoring flags.\n");
+ return false;
+ }
+ }
+ return true;
+}
+
/*
* NOTE: The caller must call lock_device_hotplug() to serialize hotplug
* and online/offline operations (triggered e.g. by sysfs).
@@ -1086,6 +1168,9 @@ int __ref add_memory_resource(int nid, struct resource *res, unsigned long flags
goto error;
new_node = ret;

+ if (mhp_check_correct_flags(flags))
+ restrictions.flags = flags;
+
/* call arch's memory hotadd */
ret = arch_add_memory(nid, start, size, &restrictions);
if (ret < 0)
@@ -1518,12 +1603,14 @@ static int __ref __offline_pages(unsigned long start_pfn,
{
unsigned long pfn, nr_pages;
unsigned long offlined_pages = 0;
+ unsigned long nr_vmemmap_pages = 0;
int ret, node, nr_isolate_pageblock;
unsigned long flags;
unsigned long valid_start, valid_end;
struct zone *zone;
struct memory_notify arg;
char *reason;
+ bool skip = false;

mem_hotplug_begin();

@@ -1540,15 +1627,24 @@ static int __ref __offline_pages(unsigned long start_pfn,
node = zone_to_nid(zone);
nr_pages = end_pfn - start_pfn;

- /* set above range as isolated */
- ret = start_isolate_page_range(start_pfn, end_pfn,
- MIGRATE_MOVABLE,
- SKIP_HWPOISON | REPORT_FAILURE);
- if (ret < 0) {
- reason = "failure to isolate range";
- goto failed_removal;
+ if (PageVmemmap(pfn_to_page(start_pfn))) {
+ nr_vmemmap_pages = get_nr_vmemmap_pages(pfn_to_page(start_pfn));
+ nr_vmemmap_pages = min(nr_vmemmap_pages, nr_pages);
+ if (nr_vmemmap_pages == nr_pages)
+ skip = true;
+ }
+
+ if (!skip) {
+ /* set above range as isolated */
+ ret = start_isolate_page_range(start_pfn, end_pfn,
+ MIGRATE_MOVABLE,
+ SKIP_HWPOISON | REPORT_FAILURE);
+ if (ret < 0) {
+ reason = "failure to isolate range";
+ goto failed_removal;
+ }
+ nr_isolate_pageblock = ret;
}
- nr_isolate_pageblock = ret;

arg.start_pfn = start_pfn;
arg.nr_pages = nr_pages;
@@ -1561,6 +1657,9 @@ static int __ref __offline_pages(unsigned long start_pfn,
goto failed_removal_isolated;
}

+ if (skip)
+ goto skip_migration;
+
do {
for (pfn = start_pfn; pfn;) {
if (signal_pending(current)) {
@@ -1601,7 +1700,9 @@ static int __ref __offline_pages(unsigned long start_pfn,
We cannot do rollback at this point. */
walk_system_ram_range(start_pfn, end_pfn - start_pfn,
&offlined_pages, offline_isolated_pages_cb);
- pr_info("Offlined Pages %ld\n", offlined_pages);
+
+skip_migration:
+ pr_info("Offlined Pages %ld\n", offlined_pages + nr_vmemmap_pages);
/*
* Onlining will reset pagetype flags and makes migrate type
* MOVABLE, so just need to decrease the number of isolated
@@ -1612,11 +1713,12 @@ static int __ref __offline_pages(unsigned long start_pfn,
spin_unlock_irqrestore(&zone->lock, flags);

/* removal success */
- adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
- zone->present_pages -= offlined_pages;
+ if (offlined_pages)
+ adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
+ zone->present_pages -= offlined_pages + nr_vmemmap_pages;

pgdat_resize_lock(zone->zone_pgdat, &flags);
- zone->zone_pgdat->node_present_pages -= offlined_pages;
+ zone->zone_pgdat->node_present_pages -= offlined_pages + nr_vmemmap_pages;
pgdat_resize_unlock(zone->zone_pgdat, &flags);

init_per_zone_wmark_min();
@@ -1645,7 +1747,7 @@ static int __ref __offline_pages(unsigned long start_pfn,
memory_notify(MEM_CANCEL_OFFLINE, &arg);
failed_removal:
pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",
- (unsigned long long) start_pfn << PAGE_SHIFT,
+ (unsigned long long) (start_pfn - nr_vmemmap_pages) << PAGE_SHIFT,
((unsigned long long) end_pfn << PAGE_SHIFT) - 1,
reason);
/* pushback to free area */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5b3266d63521..7a73a06c5730 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1282,9 +1282,14 @@ static void free_one_page(struct zone *zone,
static void __meminit __init_single_page(struct page *page, unsigned long pfn,
unsigned long zone, int nid)
{
- mm_zero_struct_page(page);
+ if (!__PageVmemmap(page)) {
+ /*
+ * Vmemmap pages need to preserve their state.
+ */
+ mm_zero_struct_page(page);
+ init_page_count(page);
+ }
set_page_links(page, zone, nid, pfn);
- init_page_count(page);
page_mapcount_reset(page);
page_cpupid_reset_last(page);
page_kasan_tag_reset(page);
@@ -8143,6 +8148,14 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count,

page = pfn_to_page(check);

+ /*
+ * Vmemmap pages are not needed to be moved around.
+ */
+ if (PageVmemmap(page)) {
+ iter += get_nr_vmemmap_pages(page) - 1;
+ continue;
+ }
+
if (PageReserved(page))
goto unmovable;

@@ -8510,6 +8523,11 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
continue;
}
page = pfn_to_page(pfn);
+
+ if (PageVmemmap(page)) {
+ pfn += get_nr_vmemmap_pages(page);
+ continue;
+ }
/*
* The HWPoisoned page may be not in buddy system, and
* page_count() is not 0.
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index e3638a5bafff..128c47a27925 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -146,7 +146,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
static inline struct page *
__first_valid_page(unsigned long pfn, unsigned long nr_pages)
{
- int i;
+ unsigned long i;

for (i = 0; i < nr_pages; i++) {
struct page *page;
@@ -154,6 +154,10 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
page = pfn_to_online_page(pfn + i);
if (!page)
continue;
+ if (PageVmemmap(page)) {
+ i += get_nr_vmemmap_pages(page) - 1;
+ continue;
+ }
return page;
}
return NULL;
@@ -268,6 +272,14 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
continue;
}
page = pfn_to_page(pfn);
+ /*
+ * Vmemmap pages are not isolated. Skip them.
+ */
+ if (PageVmemmap(page)) {
+ pfn += get_nr_vmemmap_pages(page);
+ continue;
+ }
+
if (PageBuddy(page))
/*
* If the page is on a free list, it has to be on
diff --git a/mm/sparse.c b/mm/sparse.c
index b77ca21a27a4..04b395fb4463 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -635,6 +635,94 @@ void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
#endif

#ifdef CONFIG_SPARSEMEM_VMEMMAP
+void mark_vmemmap_pages(struct vmem_altmap *self)
+{
+ unsigned long pfn = self->base_pfn + self->reserve;
+ unsigned long nr_pages = self->alloc;
+ unsigned long nr_sects = self->free / PAGES_PER_SECTION;
+ unsigned long i;
+ struct page *head;
+
+ if (!nr_pages)
+ return;
+
+ pr_debug("%s: marking %px - %px as Vmemmap (%ld pages)\n",
+ __func__,
+ pfn_to_page(pfn),
+ pfn_to_page(pfn + nr_pages - 1),
+ nr_pages);
+
+ /*
+ * All allocations for the memory hotplug are the same sized so align
+ * should be 0.
+ */
+ WARN_ON(self->align);
+
+ /*
+ * Layout of vmemmap pages:
+ * [Head->refcount] : Nr sections used by this altmap
+ * [Head->private] : Nr of vmemmap pages
+ * [Tail->freelist] : Pointer to the head page
+ */
+
+ /*
+ * Head, first vmemmap page
+ */
+ head = pfn_to_page(pfn);
+ for (i = 0; i < nr_pages; i++, pfn++) {
+ struct page *page = pfn_to_page(pfn);
+
+ mm_zero_struct_page(page);
+ __SetPageVmemmap(page);
+ page->freelist = head;
+ init_page_count(page);
+ }
+ set_page_count(head, (int)nr_sects);
+ set_page_private(head, nr_pages);
+}
+/*
+ * If the range we are trying to remove was hot-added with vmemmap pages
+ * using MHP_MEMMAP_DEVICE, we need to keep track of it to know how much
+ * do we have do defer the free up.
+ * Since sections are removed sequentally in __remove_pages()->
+ * __remove_section(), we just wait until we hit the last section.
+ * Once that happens, we can trigger free_deferred_vmemmap_range to actually
+ * free the whole memory-range.
+ */
+static struct page *head_vmemmap_page = NULL;;
+static bool freeing_vmemmap_range = false;
+
+static inline bool vmemmap_dec_and_test(void)
+{
+ return page_ref_dec_and_test(head_vmemmap_page);
+}
+
+static void free_deferred_vmemmap_range(unsigned long start,
+ unsigned long end)
+{
+ unsigned long nr_pages = end - start;
+ unsigned long first_section = (unsigned long)head_vmemmap_page;
+
+ while (start >= first_section) {
+ vmemmap_free(start, end, NULL);
+ end = start;
+ start -= nr_pages;
+ }
+ head_vmemmap_page = NULL;
+ freeing_vmemmap_range = false;
+}
+
+static void deferred_vmemmap_free(unsigned long start, unsigned long end)
+{
+ if (!freeing_vmemmap_range) {
+ freeing_vmemmap_range = true;
+ head_vmemmap_page = (struct page *)start;
+ }
+
+ if (vmemmap_dec_and_test())
+ free_deferred_vmemmap_range(start, end);
+}
+
static struct page *populate_section_memmap(unsigned long pfn,
unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
{
@@ -647,6 +735,11 @@ static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages,
unsigned long start = (unsigned long) pfn_to_page(pfn);
unsigned long end = start + nr_pages * sizeof(struct page);

+ if (PageVmemmap((struct page *)start) || freeing_vmemmap_range) {
+ deferred_vmemmap_free(start, end);
+ return;
+ }
+
vmemmap_free(start, end, altmap);
}
static void free_map_bootmem(struct page *memmap)
--
2.12.3

2019-06-25 08:26:42

Subject: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: [PATCH v2 2/5] mm,memory_hotplug: Introduce MHP_VMEMMAP_FLAGS

Subject: [PATCH v2 3/5] mm,memory_hotplug: Introduce Vmemmap page helpers

Subject: [PATCH v2 4/5] mm,memory_hotplug: allocate memmap from the added memory range for sparse-vmemmap

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 2/5] mm,memory_hotplug: Introduce MHP_VMEMMAP_FLAGS

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 4/5] mm,memory_hotplug: allocate memmap from the added memory range for sparse-vmemmap

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 4/5] mm,memory_hotplug: allocate memmap from the added memory range for sparse-vmemmap

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 4/5] mm,memory_hotplug: allocate memmap from the added memory range for sparse-vmemmap

Subject: Re: [PATCH v2 4/5] mm,memory_hotplug: allocate memmap from the added memory range for sparse-vmemmap

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 4/5] mm,memory_hotplug: allocate memmap from the added memory range for sparse-vmemmap

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 2/5] mm,memory_hotplug: Introduce MHP_VMEMMAP_FLAGS

Subject: Re: [PATCH v2 4/5] mm,memory_hotplug: allocate memmap from the added memory range for sparse-vmemmap

Subject: Re: [PATCH v2 2/5] mm,memory_hotplug: Introduce MHP_VMEMMAP_FLAGS

Subject: Re: [PATCH v2 2/5] mm,memory_hotplug: Introduce MHP_VMEMMAP_FLAGS

Subject: Re: [PATCH v2 2/5] mm,memory_hotplug: Introduce MHP_VMEMMAP_FLAGS

Subject: Re: [PATCH v2 2/5] mm,memory_hotplug: Introduce MHP_VMEMMAP_FLAGS

Subject: Re: [PATCH v2 2/5] mm,memory_hotplug: Introduce MHP_VMEMMAP_FLAGS

Subject: Re: [PATCH v2 2/5] mm,memory_hotplug: Introduce MHP_VMEMMAP_FLAGS

Subject: Re: [PATCH v2 2/5] mm,memory_hotplug: Introduce MHP_VMEMMAP_FLAGS

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory