Re: [PATCH v2 2/3] mm/memory_hotplug: split memmap_on_memory requests across memblocks
On 14.08.23 08:45, Huang, Ying wrote:
"Verma, Vishal L" writes:
On Mon, 2023-07-24 at 13:54 +0800, Huang, Ying wrote:
Vishal Verma writes:
@@ -2035,12 +2056,38 @@ void try_offline_node(int nid)
}
EXPORT_SYMBOL(try_offline_node);
-static int __ref try_remove_memory(u64 start, u64 size)
+static void __ref __try_remove_memory(int nid, u64 start, u64 size,
+struct vmem_altmap *altmap)
{
- struct vmem_altmap mhp_altmap = {};
- struct vmem_altmap *altmap = NULL;
- unsigned long nr_vmemmap_pages;
- int rc = 0, nid = NUMA_NO_NODE;
+ /* remove memmap entry */
+ firmware_map_remove(start, start + size, "System RAM");
If mhp_supports_memmap_on_memory(), we will call
firmware_map_add_hotplug() for whole range. But here we may call
firmware_map_remove() for part of range. Is it OK?
Good point, this is a discrepancy in the add vs remove path. Can the
firmware memmap entries be moved up a bit in the add path, and is it
okay to create these for each memblock? Or should these be for the
whole range? I'm not familiar with the implications. (I've left it as
is for v3 for now, but depending on the direction I can update in a
future rev).
Cced more firmware map developers and maintainers.
Per my understanding, we should create one firmware memmap entry for
each memblock.
Ideally we should create it for the whole range, ti limit the ranges.
But it really only matters for DIMMs; for dax/kmem, we'll not create any
firmware entries.
--
Cheers,
David / dhildenb
Re: [PATCH v2 2/3] mm/memory_hotplug: split memmap_on_memory requests across memblocks
"Verma, Vishal L" writes:
> On Mon, 2023-07-24 at 13:54 +0800, Huang, Ying wrote:
>> Vishal Verma writes:
>>
>> >
>> > @@ -2035,12 +2056,38 @@ void try_offline_node(int nid)
>> > }
>> > EXPORT_SYMBOL(try_offline_node);
>> >
>> > -static int __ref try_remove_memory(u64 start, u64 size)
>> > +static void __ref __try_remove_memory(int nid, u64 start, u64 size,
>> > +struct vmem_altmap *altmap)
>> > {
>> > - struct vmem_altmap mhp_altmap = {};
>> > - struct vmem_altmap *altmap = NULL;
>> > - unsigned long nr_vmemmap_pages;
>> > - int rc = 0, nid = NUMA_NO_NODE;
>> > + /* remove memmap entry */
>> > + firmware_map_remove(start, start + size, "System RAM");
>>
>> If mhp_supports_memmap_on_memory(), we will call
>> firmware_map_add_hotplug() for whole range. But here we may call
>> firmware_map_remove() for part of range. Is it OK?
>>
>
> Good point, this is a discrepancy in the add vs remove path. Can the
> firmware memmap entries be moved up a bit in the add path, and is it
> okay to create these for each memblock? Or should these be for the
> whole range? I'm not familiar with the implications. (I've left it as
> is for v3 for now, but depending on the direction I can update in a
> future rev).
Cced more firmware map developers and maintainers.
Per my understanding, we should create one firmware memmap entry for
each memblock.
--
Best Regards,
Huang, Ying
Re: [PATCH v2 2/3] mm/memory_hotplug: split memmap_on_memory requests across memblocks
"Verma, Vishal L" writes:
> On Mon, 2023-07-24 at 11:16 +0800, Huang, Ying wrote:
>> "Aneesh Kumar K.V" writes:
>> >
>> > > @@ -1339,27 +1367,20 @@ int __ref add_memory_resource(int nid,
>> > > struct resource *res, mhp_t mhp_flags)
>> > > /*
>> > > * Self hosted memmap array
>> > > */
>> > > - if (mhp_flags & MHP_MEMMAP_ON_MEMORY) {
>> > > - if (!mhp_supports_memmap_on_memory(size)) {
>> > > - ret = -EINVAL;
>> > > + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) &&
>> > > + mhp_supports_memmap_on_memory(memblock_size)) {
>> > > + for (cur_start = start; cur_start < start + size;
>> > > +cur_start += memblock_size) {
>> > > + ret = add_memory_create_devices(nid,
>> > > group, cur_start,
>> > > + memblock_
>> > > size,
>> > > + mhp_flags
>> > > );
>> > > + if (ret)
>> > > + goto error;
>> > > + }
>> >
>> > We should handle the below error details here.
>> >
>> > 1) If we hit an error after some blocks got added, should we
>> > iterate over rest of the dev_dax->nr_range.
>> > 2) With some blocks added if we return a failure here, we remove
>> > the
>> > resource in dax_kmem. Is that ok?
>> >
>> > IMHO error handling with partial creation of memory blocks in a
>> > resource range should be
>> > documented with this change.
>>
>> Or, should we remove all added memory blocks upon error?
>>
> I didn't address these in v3 - I wasn't sure how we'd proceed here.
> Something obviously went very wrong and I'd imagine it is okay if this
> memory is unusable as a result.
>
> What woyuld removing the blocks we added look like? Just call
> try_remove_memory() from the error path in add_memory_resource()? (for
> a range of [start, cur_start) ?
I guess that we can just keep the original behavior. Originally, if
something goes wrong, arch_remove_memory() and remove_memory_block() (in
create_memory_block_devices()) will be called for all added memory
range. So, we should do that too?
--
Best Regards,
Huang, Ying
Re: [PATCH v2 2/3] mm/memory_hotplug: split memmap_on_memory requests across memblocks
On Mon, 2023-07-24 at 13:54 +0800, Huang, Ying wrote:
> Vishal Verma writes:
>
> >
> > @@ -2035,12 +2056,38 @@ void try_offline_node(int nid)
> > }
> > EXPORT_SYMBOL(try_offline_node);
> >
> > -static int __ref try_remove_memory(u64 start, u64 size)
> > +static void __ref __try_remove_memory(int nid, u64 start, u64 size,
> > + struct vmem_altmap *altmap)
> > {
> > - struct vmem_altmap mhp_altmap = {};
> > - struct vmem_altmap *altmap = NULL;
> > - unsigned long nr_vmemmap_pages;
> > - int rc = 0, nid = NUMA_NO_NODE;
> > + /* remove memmap entry */
> > + firmware_map_remove(start, start + size, "System RAM");
>
> If mhp_supports_memmap_on_memory(), we will call
> firmware_map_add_hotplug() for whole range. But here we may call
> firmware_map_remove() for part of range. Is it OK?
>
Good point, this is a discrepancy in the add vs remove path. Can the
firmware memmap entries be moved up a bit in the add path, and is it
okay to create these for each memblock? Or should these be for the
whole range? I'm not familiar with the implications. (I've left it as
is for v3 for now, but depending on the direction I can update in a
future rev).
Re: [PATCH v2 2/3] mm/memory_hotplug: split memmap_on_memory requests across memblocks
On Mon, 2023-07-24 at 11:16 +0800, Huang, Ying wrote:
> "Aneesh Kumar K.V" writes:
> >
> > > @@ -1339,27 +1367,20 @@ int __ref add_memory_resource(int nid,
> > > struct resource *res, mhp_t mhp_flags)
> > > /*
> > > * Self hosted memmap array
> > > */
> > > - if (mhp_flags & MHP_MEMMAP_ON_MEMORY) {
> > > - if (!mhp_supports_memmap_on_memory(size)) {
> > > - ret = -EINVAL;
> > > + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) &&
> > > + mhp_supports_memmap_on_memory(memblock_size)) {
> > > + for (cur_start = start; cur_start < start + size;
> > > + cur_start += memblock_size) {
> > > + ret = add_memory_create_devices(nid,
> > > group, cur_start,
> > > + memblock_
> > > size,
> > > + mhp_flags
> > > );
> > > + if (ret)
> > > + goto error;
> > > + }
> >
> > We should handle the below error details here.
> >
> > 1) If we hit an error after some blocks got added, should we
> > iterate over rest of the dev_dax->nr_range.
> > 2) With some blocks added if we return a failure here, we remove
> > the
> > resource in dax_kmem. Is that ok?
> >
> > IMHO error handling with partial creation of memory blocks in a
> > resource range should be
> > documented with this change.
>
> Or, should we remove all added memory blocks upon error?
>
I didn't address these in v3 - I wasn't sure how we'd proceed here.
Something obviously went very wrong and I'd imagine it is okay if this
memory is unusable as a result.
What woyuld removing the blocks we added look like? Just call
try_remove_memory() from the error path in add_memory_resource()? (for
a range of [start, cur_start) ?
Re: [PATCH v2 2/3] mm/memory_hotplug: split memmap_on_memory requests across memblocks
Vishal Verma writes:
> The MHP_MEMMAP_ON_MEMORY flag for hotplugged memory is currently
> restricted to 'memblock_size' chunks of memory being added. Adding a
> larger span of memory precludes memmap_on_memory semantics.
>
> For users of hotplug such as kmem, large amounts of memory might get
> added from the CXL subsystem. In some cases, this amount may exceed the
> available 'main memory' to store the memmap for the memory being added.
> In this case, it is useful to have a way to place the memmap on the
> memory being added, even if it means splitting the addition into
> memblock-sized chunks.
>
> Change add_memory_resource() to loop over memblock-sized chunks of
> memory if caller requested memmap_on_memory, and if other conditions for
> it are met,. Teach try_remove_memory() to also expect that a memory
> range being removed might have been split up into memblock sized chunks,
> and to loop through those as needed.
>
> Cc: Andrew Morton
> Cc: David Hildenbrand
> Cc: Oscar Salvador
> Cc: Dan Williams
> Cc: Dave Jiang
> Cc: Dave Hansen
> Cc: Huang Ying
> Suggested-by: David Hildenbrand
> Signed-off-by: Vishal Verma
> ---
> mm/memory_hotplug.c | 154
> +++-
> 1 file changed, 91 insertions(+), 63 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index e9bcacbcbae2..20456f0d28e6 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1286,6 +1286,35 @@ bool mhp_supports_memmap_on_memory(unsigned long size)
> }
> EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
>
> +static int add_memory_create_devices(int nid, struct memory_group *group,
> + u64 start, u64 size, mhp_t mhp_flags)
> +{
> + struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
> + struct vmem_altmap mhp_altmap = {};
> + int ret;
> +
> + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY)) {
> + mhp_altmap.free = PHYS_PFN(size);
> + mhp_altmap.base_pfn = PHYS_PFN(start);
> + params.altmap = &mhp_altmap;
> + }
> +
> + /* call arch's memory hotadd */
> + ret = arch_add_memory(nid, start, size, ¶ms);
> + if (ret < 0)
> + return ret;
> +
> + /* create memory block devices after memory was added */
> + ret = create_memory_block_devices(start, size, mhp_altmap.alloc,
> + group);
> + if (ret) {
> + arch_remove_memory(start, size, NULL);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> /*
> * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
> * and online/offline operations (triggered e.g. by sysfs).
> @@ -1294,11 +1323,10 @@ EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
> */
> int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
> {
> - struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
> + unsigned long memblock_size = memory_block_size_bytes();
> enum memblock_flags memblock_flags = MEMBLOCK_NONE;
> - struct vmem_altmap mhp_altmap = {};
> struct memory_group *group = NULL;
> - u64 start, size;
> + u64 start, size, cur_start;
> bool new_node = false;
> int ret;
>
> @@ -1339,27 +1367,20 @@ int __ref add_memory_resource(int nid, struct
> resource *res, mhp_t mhp_flags)
> /*
>* Self hosted memmap array
>*/
> - if (mhp_flags & MHP_MEMMAP_ON_MEMORY) {
> - if (!mhp_supports_memmap_on_memory(size)) {
> - ret = -EINVAL;
> + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) &&
> + mhp_supports_memmap_on_memory(memblock_size)) {
> + for (cur_start = start; cur_start < start + size;
> + cur_start += memblock_size) {
> + ret = add_memory_create_devices(nid, group, cur_start,
> + memblock_size,
> + mhp_flags);
> + if (ret)
> + goto error;
> + }
> + } else {
> + ret = add_memory_create_devices(nid, group, start, size,
> mhp_flags);
> + if (ret)
> goto error;
Another choice to organize code is to use different step (memblock_size
vs. size) in "for" loop.
It's not necessary in this patchset. It appears that we cannot create
1GB mapping if we put memmap on memory now, right? If so, is it doable
to support that via separating creating memory mapping from
arch_add_memory()?
> - }
> - mhp_altmap.free = PHYS_PFN(size);
> - mhp_altmap.base_pfn = PHYS_PFN(start);
> - params.altmap = &mhp_altmap;
> - }
> -
> - /* call arch's memory hotadd */
> - ret = arch_add_memory(nid, start, size, ¶ms);
> - if (ret < 0)
> - goto error;
> -
> - /* create memory block devices
Re: [PATCH v2 2/3] mm/memory_hotplug: split memmap_on_memory requests across memblocks
"Aneesh Kumar K.V" writes:
> Vishal Verma writes:
>
>> The MHP_MEMMAP_ON_MEMORY flag for hotplugged memory is currently
>> restricted to 'memblock_size' chunks of memory being added. Adding a
>> larger span of memory precludes memmap_on_memory semantics.
>>
>> For users of hotplug such as kmem, large amounts of memory might get
>> added from the CXL subsystem. In some cases, this amount may exceed the
>> available 'main memory' to store the memmap for the memory being added.
>> In this case, it is useful to have a way to place the memmap on the
>> memory being added, even if it means splitting the addition into
>> memblock-sized chunks.
>>
>> Change add_memory_resource() to loop over memblock-sized chunks of
>> memory if caller requested memmap_on_memory, and if other conditions for
>> it are met,. Teach try_remove_memory() to also expect that a memory
>> range being removed might have been split up into memblock sized chunks,
>> and to loop through those as needed.
>>
>> Cc: Andrew Morton
>> Cc: David Hildenbrand
>> Cc: Oscar Salvador
>> Cc: Dan Williams
>> Cc: Dave Jiang
>> Cc: Dave Hansen
>> Cc: Huang Ying
>> Suggested-by: David Hildenbrand
>> Signed-off-by: Vishal Verma
>> ---
>> mm/memory_hotplug.c | 154
>> +++-
>> 1 file changed, 91 insertions(+), 63 deletions(-)
>>
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index e9bcacbcbae2..20456f0d28e6 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -1286,6 +1286,35 @@ bool mhp_supports_memmap_on_memory(unsigned long size)
>> }
>> EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
>>
>> +static int add_memory_create_devices(int nid, struct memory_group *group,
>> + u64 start, u64 size, mhp_t mhp_flags)
>> +{
>> +struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
>> +struct vmem_altmap mhp_altmap = {};
>> +int ret;
>> +
>> +if ((mhp_flags & MHP_MEMMAP_ON_MEMORY)) {
>> +mhp_altmap.free = PHYS_PFN(size);
>> +mhp_altmap.base_pfn = PHYS_PFN(start);
>> +params.altmap = &mhp_altmap;
>> +}
>> +
>> +/* call arch's memory hotadd */
>> +ret = arch_add_memory(nid, start, size, ¶ms);
>> +if (ret < 0)
>> +return ret;
>> +
>> +/* create memory block devices after memory was added */
>> +ret = create_memory_block_devices(start, size, mhp_altmap.alloc,
>> + group);
>> +if (ret) {
>> +arch_remove_memory(start, size, NULL);
>> +return ret;
>> +}
>> +
>> +return 0;
>> +}
>> +
>> /*
>> * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
>> * and online/offline operations (triggered e.g. by sysfs).
>> @@ -1294,11 +1323,10 @@ EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
>> */
>> int __ref add_memory_resource(int nid, struct resource *res, mhp_t
>> mhp_flags)
>> {
>> -struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
>> +unsigned long memblock_size = memory_block_size_bytes();
>> enum memblock_flags memblock_flags = MEMBLOCK_NONE;
>> -struct vmem_altmap mhp_altmap = {};
>> struct memory_group *group = NULL;
>> -u64 start, size;
>> +u64 start, size, cur_start;
>> bool new_node = false;
>> int ret;
>>
>> @@ -1339,27 +1367,20 @@ int __ref add_memory_resource(int nid, struct
>> resource *res, mhp_t mhp_flags)
>> /*
>> * Self hosted memmap array
>> */
>> -if (mhp_flags & MHP_MEMMAP_ON_MEMORY) {
>> -if (!mhp_supports_memmap_on_memory(size)) {
>> -ret = -EINVAL;
>> +if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) &&
>> +mhp_supports_memmap_on_memory(memblock_size)) {
>> +for (cur_start = start; cur_start < start + size;
>> + cur_start += memblock_size) {
>> +ret = add_memory_create_devices(nid, group, cur_start,
>> +memblock_size,
>> +mhp_flags);
>> +if (ret)
>> +goto error;
>> +}
>
> We should handle the below error details here.
>
> 1) If we hit an error after some blocks got added, should we iterate over
> rest of the dev_dax->nr_range.
> 2) With some blocks added if we return a failure here, we remove the
> resource in dax_kmem. Is that ok?
>
> IMHO error handling with partial creation of memory blocks in a resource
> range should be
> documented with this change.
Or, should we remove all added memory blocks upon error?
--
Best Regards,
Huang, Ying
Re: [PATCH v2 2/3] mm/memory_hotplug: split memmap_on_memory requests across memblocks
Vishal Verma writes:
> The MHP_MEMMAP_ON_MEMORY flag for hotplugged memory is currently
> restricted to 'memblock_size' chunks of memory being added. Adding a
> larger span of memory precludes memmap_on_memory semantics.
>
> For users of hotplug such as kmem, large amounts of memory might get
> added from the CXL subsystem. In some cases, this amount may exceed the
> available 'main memory' to store the memmap for the memory being added.
> In this case, it is useful to have a way to place the memmap on the
> memory being added, even if it means splitting the addition into
> memblock-sized chunks.
>
> Change add_memory_resource() to loop over memblock-sized chunks of
> memory if caller requested memmap_on_memory, and if other conditions for
> it are met,. Teach try_remove_memory() to also expect that a memory
> range being removed might have been split up into memblock sized chunks,
> and to loop through those as needed.
>
> Cc: Andrew Morton
> Cc: David Hildenbrand
> Cc: Oscar Salvador
> Cc: Dan Williams
> Cc: Dave Jiang
> Cc: Dave Hansen
> Cc: Huang Ying
> Suggested-by: David Hildenbrand
> Signed-off-by: Vishal Verma
> ---
> mm/memory_hotplug.c | 154
> +++-
> 1 file changed, 91 insertions(+), 63 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index e9bcacbcbae2..20456f0d28e6 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1286,6 +1286,35 @@ bool mhp_supports_memmap_on_memory(unsigned long size)
> }
> EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
>
> +static int add_memory_create_devices(int nid, struct memory_group *group,
> + u64 start, u64 size, mhp_t mhp_flags)
> +{
> + struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
> + struct vmem_altmap mhp_altmap = {};
> + int ret;
> +
> + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY)) {
> + mhp_altmap.free = PHYS_PFN(size);
> + mhp_altmap.base_pfn = PHYS_PFN(start);
> + params.altmap = &mhp_altmap;
> + }
> +
> + /* call arch's memory hotadd */
> + ret = arch_add_memory(nid, start, size, ¶ms);
> + if (ret < 0)
> + return ret;
> +
> + /* create memory block devices after memory was added */
> + ret = create_memory_block_devices(start, size, mhp_altmap.alloc,
> + group);
> + if (ret) {
> + arch_remove_memory(start, size, NULL);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> /*
> * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
> * and online/offline operations (triggered e.g. by sysfs).
> @@ -1294,11 +1323,10 @@ EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
> */
> int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
> {
> - struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
> + unsigned long memblock_size = memory_block_size_bytes();
> enum memblock_flags memblock_flags = MEMBLOCK_NONE;
> - struct vmem_altmap mhp_altmap = {};
> struct memory_group *group = NULL;
> - u64 start, size;
> + u64 start, size, cur_start;
> bool new_node = false;
> int ret;
>
> @@ -1339,27 +1367,20 @@ int __ref add_memory_resource(int nid, struct
> resource *res, mhp_t mhp_flags)
> /*
>* Self hosted memmap array
>*/
> - if (mhp_flags & MHP_MEMMAP_ON_MEMORY) {
> - if (!mhp_supports_memmap_on_memory(size)) {
> - ret = -EINVAL;
> + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) &&
> + mhp_supports_memmap_on_memory(memblock_size)) {
> + for (cur_start = start; cur_start < start + size;
> + cur_start += memblock_size) {
> + ret = add_memory_create_devices(nid, group, cur_start,
> + memblock_size,
> + mhp_flags);
> + if (ret)
> + goto error;
> + }
We should handle the below error details here.
1) If we hit an error after some blocks got added, should we iterate over rest
of the dev_dax->nr_range.
2) With some blocks added if we return a failure here, we remove the
resource in dax_kmem. Is that ok?
IMHO error handling with partial creation of memory blocks in a resource range
should be
documented with this change.
> + } else {
> + ret = add_memory_create_devices(nid, group, start, size,
> mhp_flags);
> + if (ret)
> goto error;
> - }
> - mhp_altmap.free = PHYS_PFN(size);
> - mhp_altmap.base_pfn = PHYS_PFN(start);
> - params.altmap = &mhp_altmap;
> - }
> -
> - /* call arch's memory hotadd */
> - ret = arch_add_memory(nid, start, size, ¶ms);
> - if (ret < 0)
> -
Re: [PATCH v2 2/3] mm/memory_hotplug: split memmap_on_memory requests across memblocks
Vishal Verma writes:
> The MHP_MEMMAP_ON_MEMORY flag for hotplugged memory is currently
> restricted to 'memblock_size' chunks of memory being added. Adding a
> larger span of memory precludes memmap_on_memory semantics.
>
> For users of hotplug such as kmem, large amounts of memory might get
> added from the CXL subsystem. In some cases, this amount may exceed the
> available 'main memory' to store the memmap for the memory being added.
> In this case, it is useful to have a way to place the memmap on the
> memory being added, even if it means splitting the addition into
> memblock-sized chunks.
>
> Change add_memory_resource() to loop over memblock-sized chunks of
> memory if caller requested memmap_on_memory, and if other conditions for
> it are met,. Teach try_remove_memory() to also expect that a memory
> range being removed might have been split up into memblock sized chunks,
> and to loop through those as needed.
>
This conflicts with
https://lore.kernel.org/linux-mm/20230718024409.95742-1-aneesh.ku...@linux.ibm.com/
IIUC Andrew was planning add that series to -mm. Also that patchset makes
some of related changes in this patch not required. Can you rebase this
series on top of that ?
>
> Cc: Andrew Morton
> Cc: David Hildenbrand
> Cc: Oscar Salvador
> Cc: Dan Williams
> Cc: Dave Jiang
> Cc: Dave Hansen
> Cc: Huang Ying
> Suggested-by: David Hildenbrand
> Signed-off-by: Vishal Verma
> ---
> mm/memory_hotplug.c | 154
> +++-
> 1 file changed, 91 insertions(+), 63 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index e9bcacbcbae2..20456f0d28e6 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1286,6 +1286,35 @@ bool mhp_supports_memmap_on_memory(unsigned long size)
> }
> EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
>
> +static int add_memory_create_devices(int nid, struct memory_group *group,
> + u64 start, u64 size, mhp_t mhp_flags)
> +{
> + struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
> + struct vmem_altmap mhp_altmap = {};
> + int ret;
> +
> + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY)) {
> + mhp_altmap.free = PHYS_PFN(size);
> + mhp_altmap.base_pfn = PHYS_PFN(start);
> + params.altmap = &mhp_altmap;
> + }
> +
> + /* call arch's memory hotadd */
> + ret = arch_add_memory(nid, start, size, ¶ms);
> + if (ret < 0)
> + return ret;
> +
> + /* create memory block devices after memory was added */
> + ret = create_memory_block_devices(start, size, mhp_altmap.alloc,
> + group);
> + if (ret) {
> + arch_remove_memory(start, size, NULL);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> /*
> * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
> * and online/offline operations (triggered e.g. by sysfs).
> @@ -1294,11 +1323,10 @@ EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
> */
> int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
> {
> - struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
> + unsigned long memblock_size = memory_block_size_bytes();
> enum memblock_flags memblock_flags = MEMBLOCK_NONE;
> - struct vmem_altmap mhp_altmap = {};
> struct memory_group *group = NULL;
> - u64 start, size;
> + u64 start, size, cur_start;
> bool new_node = false;
> int ret;
>
> @@ -1339,27 +1367,20 @@ int __ref add_memory_resource(int nid, struct
> resource *res, mhp_t mhp_flags)
> /*
>* Self hosted memmap array
>*/
> - if (mhp_flags & MHP_MEMMAP_ON_MEMORY) {
> - if (!mhp_supports_memmap_on_memory(size)) {
> - ret = -EINVAL;
> + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) &&
> + mhp_supports_memmap_on_memory(memblock_size)) {
> + for (cur_start = start; cur_start < start + size;
> + cur_start += memblock_size) {
> + ret = add_memory_create_devices(nid, group, cur_start,
> + memblock_size,
> + mhp_flags);
> + if (ret)
> + goto error;
> + }
> + } else {
> + ret = add_memory_create_devices(nid, group, start, size,
> mhp_flags);
> + if (ret)
> goto error;
> - }
> - mhp_altmap.free = PHYS_PFN(size);
> - mhp_altmap.base_pfn = PHYS_PFN(start);
> - params.altmap = &mhp_altmap;
> - }
> -
> - /* call arch's memory hotadd */
> - ret = arch_add_memory(nid, start, size, ¶ms);
> - if (ret < 0)
> - goto error;
> -
> - /* create memory block devices after memory was added */
> - ret =
[PATCH v2 2/3] mm/memory_hotplug: split memmap_on_memory requests across memblocks
The MHP_MEMMAP_ON_MEMORY flag for hotplugged memory is currently
restricted to 'memblock_size' chunks of memory being added. Adding a
larger span of memory precludes memmap_on_memory semantics.
For users of hotplug such as kmem, large amounts of memory might get
added from the CXL subsystem. In some cases, this amount may exceed the
available 'main memory' to store the memmap for the memory being added.
In this case, it is useful to have a way to place the memmap on the
memory being added, even if it means splitting the addition into
memblock-sized chunks.
Change add_memory_resource() to loop over memblock-sized chunks of
memory if caller requested memmap_on_memory, and if other conditions for
it are met,. Teach try_remove_memory() to also expect that a memory
range being removed might have been split up into memblock sized chunks,
and to loop through those as needed.
Cc: Andrew Morton
Cc: David Hildenbrand
Cc: Oscar Salvador
Cc: Dan Williams
Cc: Dave Jiang
Cc: Dave Hansen
Cc: Huang Ying
Suggested-by: David Hildenbrand
Signed-off-by: Vishal Verma
---
mm/memory_hotplug.c | 154 +++-
1 file changed, 91 insertions(+), 63 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e9bcacbcbae2..20456f0d28e6 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1286,6 +1286,35 @@ bool mhp_supports_memmap_on_memory(unsigned long size)
}
EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
+static int add_memory_create_devices(int nid, struct memory_group *group,
+u64 start, u64 size, mhp_t mhp_flags)
+{
+ struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
+ struct vmem_altmap mhp_altmap = {};
+ int ret;
+
+ if ((mhp_flags & MHP_MEMMAP_ON_MEMORY)) {
+ mhp_altmap.free = PHYS_PFN(size);
+ mhp_altmap.base_pfn = PHYS_PFN(start);
+ params.altmap = &mhp_altmap;
+ }
+
+ /* call arch's memory hotadd */
+ ret = arch_add_memory(nid, start, size, ¶ms);
+ if (ret < 0)
+ return ret;
+
+ /* create memory block devices after memory was added */
+ ret = create_memory_block_devices(start, size, mhp_altmap.alloc,
+ group);
+ if (ret) {
+ arch_remove_memory(start, size, NULL);
+ return ret;
+ }
+
+ return 0;
+}
+
/*
* NOTE: The caller must call lock_device_hotplug() to serialize hotplug
* and online/offline operations (triggered e.g. by sysfs).
@@ -1294,11 +1323,10 @@ EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
*/
int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
{
- struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
+ unsigned long memblock_size = memory_block_size_bytes();
enum memblock_flags memblock_flags = MEMBLOCK_NONE;
- struct vmem_altmap mhp_altmap = {};
struct memory_group *group = NULL;
- u64 start, size;
+ u64 start, size, cur_start;
bool new_node = false;
int ret;
@@ -1339,27 +1367,20 @@ int __ref add_memory_resource(int nid, struct resource
*res, mhp_t mhp_flags)
/*
* Self hosted memmap array
*/
- if (mhp_flags & MHP_MEMMAP_ON_MEMORY) {
- if (!mhp_supports_memmap_on_memory(size)) {
- ret = -EINVAL;
+ if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) &&
+ mhp_supports_memmap_on_memory(memblock_size)) {
+ for (cur_start = start; cur_start < start + size;
+cur_start += memblock_size) {
+ ret = add_memory_create_devices(nid, group, cur_start,
+ memblock_size,
+ mhp_flags);
+ if (ret)
+ goto error;
+ }
+ } else {
+ ret = add_memory_create_devices(nid, group, start, size,
mhp_flags);
+ if (ret)
goto error;
- }
- mhp_altmap.free = PHYS_PFN(size);
- mhp_altmap.base_pfn = PHYS_PFN(start);
- params.altmap = &mhp_altmap;
- }
-
- /* call arch's memory hotadd */
- ret = arch_add_memory(nid, start, size, ¶ms);
- if (ret < 0)
- goto error;
-
- /* create memory block devices after memory was added */
- ret = create_memory_block_devices(start, size, mhp_altmap.alloc,
- group);
- if (ret) {
- arch_remove_memory(start, size, NULL);
- goto error;
}
if (new_node) {
@@ -2035,12 +2056,38 @@ void try_offline_node(int nid)
}
EXPORT_SYMBOL(try_offline_node);
-static int __ref try_remove_memory(u64 start, u64 size)
+static void __ref __tr
