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

Joao Martins
2021-03-25T23:10:42Z

@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(-)

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);

--
2.17.1