diff mbox series

[v1,05/11] mm/sparse-vmemmap: add a pgmap argument to section activation

Message ID 20210325230938.30752-6-joao.m.martins@oracle.com (mailing list archive)
State New, archived
Headers show
Series mm, sparse-vmemmap: Introduce compound pagemaps | expand

Commit Message

Joao Martins March 25, 2021, 11:09 p.m. UTC 
@altmap is stored in a dev_pagemap, but it will be repurposed for
hotplug memory for storing the memmap in the hotplugged memory[*] and
reusing the altmap infrastructure to that end. This is to say that
altmap can't be replaced with a @pgmap as it is going to cover more than
dev_pagemap backend altmaps.

So in addition to @altmap, pass @pgmap to sparse section populate
functions namely:

	sparse_add_section
	  section_activate
	    populate_section_memmap
   	      __populate_section_memmap

Passing @pgmap allows __populate_section_memmap() to both fetch the align
in which memmap metadata is created for and also to let sparse-vmemmap
fetch pgmap ranges to co-relate to a given section and pick whether to just
reuse tail pages from past onlined sections.

[*] https://lore.kernel.org/linux-mm/20210319092635.6214-1-osalvador@suse.de/

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
 include/linux/memory_hotplug.h |  5 ++++-
 include/linux/mm.h             |  3 ++-
 mm/memory_hotplug.c            |  3 ++-
 mm/sparse-vmemmap.c            |  3 ++-
 mm/sparse.c                    | 24 +++++++++++++++---------
 5 files changed, 25 insertions(+), 13 deletions(-)

Comments

Dan Williams May 5, 2021, 10:34 p.m. UTC | #1 
On Thu, Mar 25, 2021 at 4:10 PM Joao Martins <joao.m.martins@oracle.com> wrote:
>
> @altmap is stored in a dev_pagemap, but it will be repurposed for
> hotplug memory for storing the memmap in the hotplugged memory[*] and
> reusing the altmap infrastructure to that end. This is to say that
> altmap can't be replaced with a @pgmap as it is going to cover more than
> dev_pagemap backend altmaps.

I was going to say, just pass the pgmap and lookup the altmap from
pgmap, but Oscar added a use case for altmap independent of pgmap. So
you might refresh this commit message to clarify why passing pgmap by
itself is not sufficient.

Other than that, looks good.
Joao Martins May 5, 2021, 10:37 p.m. UTC | #2 
On 5/5/21 11:34 PM, Dan Williams wrote:
> On Thu, Mar 25, 2021 at 4:10 PM Joao Martins <joao.m.martins@oracle.com> wrote:
>>
>> @altmap is stored in a dev_pagemap, but it will be repurposed for
>> hotplug memory for storing the memmap in the hotplugged memory[*] and
>> reusing the altmap infrastructure to that end. This is to say that
>> altmap can't be replaced with a @pgmap as it is going to cover more than
>> dev_pagemap backend altmaps.
> 
> I was going to say, just pass the pgmap and lookup the altmap from
> pgmap, but Oscar added a use case for altmap independent of pgmap. So
> you might refresh this commit message to clarify why passing pgmap by
> itself is not sufficient.
> 
Isn't that what I am doing above with that exact paragraph? I even
reference his series at the end of commit description :) in [*]

> Other than that, looks good.
> 
/me nods
Dan Williams May 5, 2021, 11:14 p.m. UTC | #3 
On Wed, May 5, 2021 at 3:38 PM Joao Martins <joao.m.martins@oracle.com> wrote:
>
>
>
> On 5/5/21 11:34 PM, Dan Williams wrote:
> > On Thu, Mar 25, 2021 at 4:10 PM Joao Martins <joao.m.martins@oracle.com> wrote:
> >>
> >> @altmap is stored in a dev_pagemap, but it will be repurposed for
> >> hotplug memory for storing the memmap in the hotplugged memory[*] and
> >> reusing the altmap infrastructure to that end. This is to say that
> >> altmap can't be replaced with a @pgmap as it is going to cover more than
> >> dev_pagemap backend altmaps.
> >
> > I was going to say, just pass the pgmap and lookup the altmap from
> > pgmap, but Oscar added a use case for altmap independent of pgmap. So
> > you might refresh this commit message to clarify why passing pgmap by
> > itself is not sufficient.
> >
> Isn't that what I am doing above with that exact paragraph? I even
> reference his series at the end of commit description :) in [*]

Oh, sorry, it didn't hit me explicitly that you were talking about
Oscar's work I thought you were referring to your own changes in this
set. I see it now... at a minimum the tense needs updating since
Oscar's changes are in the past not the future anymore. If it helps,
the following reads more direct to me: "In support of using compound
pages for devmap mappings, plumb the pgmap down to the
vmemmap_populate* implementation. Note that while altmap is
retrievable from pgmap the memory hotplug codes passes altmap without
pgmap, so both need to be independently plumbed."
Joao Martins May 6, 2021, 10:24 a.m. UTC | #4 
On 5/6/21 12:14 AM, Dan Williams wrote:
> On Wed, May 5, 2021 at 3:38 PM Joao Martins <joao.m.martins@oracle.com> wrote:
>>
>>
>>
>> On 5/5/21 11:34 PM, Dan Williams wrote:
>>> On Thu, Mar 25, 2021 at 4:10 PM Joao Martins <joao.m.martins@oracle.com> wrote:
>>>>
>>>> @altmap is stored in a dev_pagemap, but it will be repurposed for
>>>> hotplug memory for storing the memmap in the hotplugged memory[*] and
>>>> reusing the altmap infrastructure to that end. This is to say that
>>>> altmap can't be replaced with a @pgmap as it is going to cover more than
>>>> dev_pagemap backend altmaps.
>>>
>>> I was going to say, just pass the pgmap and lookup the altmap from
>>> pgmap, but Oscar added a use case for altmap independent of pgmap. So
>>> you might refresh this commit message to clarify why passing pgmap by
>>> itself is not sufficient.
>>>
>> Isn't that what I am doing above with that exact paragraph? I even
>> reference his series at the end of commit description :) in [*]
> 
> Oh, sorry, it didn't hit me explicitly that you were talking about
> Oscar's work I thought you were referring to your own changes in this
> set. I see it now... at a minimum the tense needs updating since
> Oscar's changes are in the past not the future anymore. 

/me nods

> If it helps,
> the following reads more direct to me: "In support of using compound
> pages for devmap mappings, plumb the pgmap down to the
> vmemmap_populate* implementation. Note that while altmap is
> retrievable from pgmap the memory hotplug codes passes altmap without
> pgmap, so both need to be independently plumbed."
> 
Let me use this one instead, definitely better than my strange english :)
diff mbox series

Patch

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index a85d4b7d15c2..45532192934c 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -14,6 +14,7 @@  struct mem_section;
 struct memory_block;
 struct resource;
 struct vmem_altmap;
+struct dev_pagemap;
 
 #ifdef CONFIG_MEMORY_HOTPLUG
 struct page *pfn_to_online_page(unsigned long pfn);
@@ -72,6 +73,7 @@  typedef int __bitwise mhp_t;
 struct mhp_params {
 	struct vmem_altmap *altmap;
 	pgprot_t pgprot;
+	struct dev_pagemap *pgmap;
 };
 
 bool mhp_range_allowed(u64 start, u64 size, bool need_mapping);
@@ -360,7 +362,8 @@  extern void remove_pfn_range_from_zone(struct zone *zone,
 				       unsigned long nr_pages);
 extern bool is_memblock_offlined(struct memory_block *mem);
 extern int sparse_add_section(int nid, unsigned long pfn,
-		unsigned long nr_pages, struct vmem_altmap *altmap);
+		unsigned long nr_pages, struct vmem_altmap *altmap,
+		struct dev_pagemap *pgmap);
 extern void sparse_remove_section(struct mem_section *ms,
 		unsigned long pfn, unsigned long nr_pages,
 		unsigned long map_offset, struct vmem_altmap *altmap);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index cb1e191da319..61474602c2b1 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3033,7 +3033,8 @@  static inline void print_vma_addr(char *prefix, unsigned long rip)
 
 void *sparse_buffer_alloc(unsigned long size);
 struct page * __populate_section_memmap(unsigned long pfn,
-		unsigned long nr_pages, int nid, struct vmem_altmap *altmap);
+		unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
+		struct dev_pagemap *pgmap);
 pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
 p4d_t *vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node);
 pud_t *vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e0b499a1fee4..2df3b2a7b4b5 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -384,7 +384,8 @@  int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
 		/* Select all remaining pages up to the next section boundary */
 		cur_nr_pages = min(end_pfn - pfn,
 				   SECTION_ALIGN_UP(pfn + 1) - pfn);
-		err = sparse_add_section(nid, pfn, cur_nr_pages, altmap);
+		err = sparse_add_section(nid, pfn, cur_nr_pages, altmap,
+					 params->pgmap);
 		if (err)
 			break;
 		cond_resched();
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index 16183d85a7d5..370728c206ee 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -249,7 +249,8 @@  int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end,
 }
 
 struct page * __meminit __populate_section_memmap(unsigned long pfn,
-		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
+		unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
+		struct dev_pagemap *pgmap)
 {
 	unsigned long start = (unsigned long) pfn_to_page(pfn);
 	unsigned long end = start + nr_pages * sizeof(struct page);
diff --git a/mm/sparse.c b/mm/sparse.c
index be66a62e22c3..c2abf1281a89 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -443,7 +443,8 @@  static unsigned long __init section_map_size(void)
 }
 
 struct page __init *__populate_section_memmap(unsigned long pfn,
-		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
+		unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
+		struct dev_pagemap *pgmap)
 {
 	unsigned long size = section_map_size();
 	struct page *map = sparse_buffer_alloc(size);
@@ -542,7 +543,7 @@  static void __init sparse_init_nid(int nid, unsigned long pnum_begin,
 			break;
 
 		map = __populate_section_memmap(pfn, PAGES_PER_SECTION,
-				nid, NULL);
+				nid, NULL, NULL);
 		if (!map) {
 			pr_err("%s: node[%d] memory map backing failed. Some memory will not be available.",
 			       __func__, nid);
@@ -648,9 +649,10 @@  void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
 
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 static struct page * __meminit populate_section_memmap(unsigned long pfn,
-		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
+		unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
+		struct dev_pagemap *pgmap)
 {
-	return __populate_section_memmap(pfn, nr_pages, nid, altmap);
+	return __populate_section_memmap(pfn, nr_pages, nid, altmap, pgmap);
 }
 
 static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages,
@@ -719,7 +721,8 @@  static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages)
 }
 #else
 struct page * __meminit populate_section_memmap(unsigned long pfn,
-		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
+		unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
+		struct dev_pagemap *pgmap)
 {
 	return kvmalloc_node(array_size(sizeof(struct page),
 					PAGES_PER_SECTION), GFP_KERNEL, nid);
@@ -842,7 +845,8 @@  static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
 }
 
 static struct page * __meminit section_activate(int nid, unsigned long pfn,
-		unsigned long nr_pages, struct vmem_altmap *altmap)
+		unsigned long nr_pages, struct vmem_altmap *altmap,
+		struct dev_pagemap *pgmap)
 {
 	struct mem_section *ms = __pfn_to_section(pfn);
 	struct mem_section_usage *usage = NULL;
@@ -874,7 +878,7 @@  static struct page * __meminit section_activate(int nid, unsigned long pfn,
 	if (nr_pages < PAGES_PER_SECTION && early_section(ms))
 		return pfn_to_page(pfn);
 
-	memmap = populate_section_memmap(pfn, nr_pages, nid, altmap);
+	memmap = populate_section_memmap(pfn, nr_pages, nid, altmap, pgmap);
 	if (!memmap) {
 		section_deactivate(pfn, nr_pages, altmap);
 		return ERR_PTR(-ENOMEM);
@@ -889,6 +893,7 @@  static struct page * __meminit section_activate(int nid, unsigned long pfn,
  * @start_pfn: start pfn of the memory range
  * @nr_pages: number of pfns to add in the section
  * @altmap: device page map
+ * @pgmap: device page map object that owns the section
  *
  * This is only intended for hotplug.
  *
@@ -902,7 +907,8 @@  static struct page * __meminit section_activate(int nid, unsigned long pfn,
  * * -ENOMEM	- Out of memory.
  */
 int __meminit sparse_add_section(int nid, unsigned long start_pfn,
-		unsigned long nr_pages, struct vmem_altmap *altmap)
+		unsigned long nr_pages, struct vmem_altmap *altmap,
+		struct dev_pagemap *pgmap)
 {
 	unsigned long section_nr = pfn_to_section_nr(start_pfn);
 	struct mem_section *ms;
@@ -913,7 +919,7 @@  int __meminit sparse_add_section(int nid, unsigned long start_pfn,
 	if (ret < 0)
 		return ret;
 
-	memmap = section_activate(nid, start_pfn, nr_pages, altmap);
+	memmap = section_activate(nid, start_pfn, nr_pages, altmap, pgmap);
 	if (IS_ERR(memmap))
 		return PTR_ERR(memmap);