forked from mirrors/linux
mm/sparsemem: support sub-section hotplug
The libnvdimm sub-system has suffered a series of hacks and broken
workarounds for the memory-hotplug implementation's awkward
section-aligned (128MB) granularity.
For example the following backtrace is emitted when attempting
arch_add_memory() with physical address ranges that intersect 'System
RAM' (RAM) with 'Persistent Memory' (PMEM) within a given section:
# cat /proc/iomem | grep -A1 -B1 Persistent\ Memory
100000000-1ffffffff : System RAM
200000000-303ffffff : Persistent Memory (legacy)
304000000-43fffffff : System RAM
440000000-23ffffffff : Persistent Memory
2400000000-43bfffffff : Persistent Memory
2400000000-43bfffffff : namespace2.0
WARNING: CPU: 38 PID: 928 at arch/x86/mm/init_64.c:850 add_pages+0x5c/0x60
[..]
RIP: 0010:add_pages+0x5c/0x60
[..]
Call Trace:
devm_memremap_pages+0x460/0x6e0
pmem_attach_disk+0x29e/0x680 [nd_pmem]
? nd_dax_probe+0xfc/0x120 [libnvdimm]
nvdimm_bus_probe+0x66/0x160 [libnvdimm]
It was discovered that the problem goes beyond RAM vs PMEM collisions as
some platform produce PMEM vs PMEM collisions within a given section.
The libnvdimm workaround for that case revealed that the libnvdimm
section-alignment-padding implementation has been broken for a long
while.
A fix for that long-standing breakage introduces as many problems as it
solves as it would require a backward-incompatible change to the
namespace metadata interpretation. Instead of that dubious route [1],
address the root problem in the memory-hotplug implementation.
Note that EEXIST is no longer treated as success as that is how
sparse_add_section() reports subsection collisions, it was also obviated
by recent changes to perform the request_region() for 'System RAM'
before arch_add_memory() in the add_memory() sequence.
[1] https://lore.kernel.org/r/155000671719.348031.2347363160141119237.stgit@dwillia2-desk3.amr.corp.intel.com
[osalvador@suse.de: fix deactivate_section for early sections]
Link: http://lkml.kernel.org/r/20190715081549.32577-2-osalvador@suse.de
Link: http://lkml.kernel.org/r/156092354368.979959.6232443923440952359.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64]
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dan Williams
Linus Torvalds
parent
7ea6216049
commit
ba72b4c8cf
4 changed files with 141 additions and 96 deletions
|
|
@ -348,7 +348,7 @@ extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
|
|||
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);
|
||||
extern void sparse_remove_one_section(struct mem_section *ms,
|
||||
extern void sparse_remove_section(struct mem_section *ms,
|
||||
unsigned long pfn, unsigned long nr_pages,
|
||||
unsigned long map_offset, struct vmem_altmap *altmap);
|
||||
extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
|
||||
|
|
|
|||
|
|
@ -252,18 +252,6 @@ void __init register_page_bootmem_info_node(struct pglist_data *pgdat)
|
|||
}
|
||||
#endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
|
||||
|
||||
static int __meminit __add_section(int nid, unsigned long pfn,
|
||||
unsigned long nr_pages, struct vmem_altmap *altmap)
|
||||
{
|
||||
int ret;
|
||||
|
||||
if (pfn_valid(pfn))
|
||||
return -EEXIST;
|
||||
|
||||
ret = sparse_add_section(nid, pfn, nr_pages, altmap);
|
||||
return ret < 0 ? ret : 0;
|
||||
}
|
||||
|
||||
static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
|
||||
const char *reason)
|
||||
{
|
||||
|
|
@ -327,18 +315,11 @@ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
|
|||
|
||||
pfns = min(nr_pages, PAGES_PER_SECTION
|
||||
- (pfn & ~PAGE_SECTION_MASK));
|
||||
err = __add_section(nid, pfn, pfns, altmap);
|
||||
err = sparse_add_section(nid, pfn, pfns, altmap);
|
||||
if (err)
|
||||
break;
|
||||
pfn += pfns;
|
||||
nr_pages -= pfns;
|
||||
|
||||
/*
|
||||
* EEXIST is finally dealt with by ioresource collision
|
||||
* check. see add_memory() => register_memory_resource()
|
||||
* Warning will be printed if there is collision.
|
||||
*/
|
||||
if (err && (err != -EEXIST))
|
||||
break;
|
||||
err = 0;
|
||||
cond_resched();
|
||||
}
|
||||
vmemmap_populate_print_last();
|
||||
|
|
@ -541,7 +522,7 @@ static void __remove_section(struct zone *zone, unsigned long pfn,
|
|||
return;
|
||||
|
||||
__remove_zone(zone, pfn, nr_pages);
|
||||
sparse_remove_one_section(ms, pfn, nr_pages, map_offset, altmap);
|
||||
sparse_remove_section(ms, pfn, nr_pages, map_offset, altmap);
|
||||
}
|
||||
|
||||
/**
|
||||
|
|
|
|||
|
|
@ -5974,7 +5974,7 @@ void __ref memmap_init_zone_device(struct zone *zone,
|
|||
* pfn out of zone.
|
||||
*
|
||||
* Please note that MEMMAP_HOTPLUG path doesn't clear memmap
|
||||
* because this is done early in sparse_add_one_section
|
||||
* because this is done early in section_activate()
|
||||
*/
|
||||
if (!(pfn & (pageblock_nr_pages - 1))) {
|
||||
set_pageblock_migratetype(page, MIGRATE_MOVABLE);
|
||||
|
|
|
|||
206
mm/sparse.c
206
mm/sparse.c
|
|
@ -83,8 +83,15 @@ static int __meminit sparse_index_init(unsigned long section_nr, int nid)
|
|||
unsigned long root = SECTION_NR_TO_ROOT(section_nr);
|
||||
struct mem_section *section;
|
||||
|
||||
/*
|
||||
* An existing section is possible in the sub-section hotplug
|
||||
* case. First hot-add instantiates, follow-on hot-add reuses
|
||||
* the existing section.
|
||||
*
|
||||
* The mem_hotplug_lock resolves the apparent race below.
|
||||
*/
|
||||
if (mem_section[root])
|
||||
return -EEXIST;
|
||||
return 0;
|
||||
|
||||
section = sparse_index_alloc(nid);
|
||||
if (!section)
|
||||
|
|
@ -715,10 +722,120 @@ static void free_map_bootmem(struct page *memmap)
|
|||
}
|
||||
#endif /* CONFIG_SPARSEMEM_VMEMMAP */
|
||||
|
||||
static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
|
||||
struct vmem_altmap *altmap)
|
||||
{
|
||||
DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
|
||||
DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 };
|
||||
struct mem_section *ms = __pfn_to_section(pfn);
|
||||
bool section_is_early = early_section(ms);
|
||||
struct page *memmap = NULL;
|
||||
unsigned long *subsection_map = ms->usage
|
||||
? &ms->usage->subsection_map[0] : NULL;
|
||||
|
||||
subsection_mask_set(map, pfn, nr_pages);
|
||||
if (subsection_map)
|
||||
bitmap_and(tmp, map, subsection_map, SUBSECTIONS_PER_SECTION);
|
||||
|
||||
if (WARN(!subsection_map || !bitmap_equal(tmp, map, SUBSECTIONS_PER_SECTION),
|
||||
"section already deactivated (%#lx + %ld)\n",
|
||||
pfn, nr_pages))
|
||||
return;
|
||||
|
||||
/*
|
||||
* There are 3 cases to handle across two configurations
|
||||
* (SPARSEMEM_VMEMMAP={y,n}):
|
||||
*
|
||||
* 1/ deactivation of a partial hot-added section (only possible
|
||||
* in the SPARSEMEM_VMEMMAP=y case).
|
||||
* a/ section was present at memory init
|
||||
* b/ section was hot-added post memory init
|
||||
* 2/ deactivation of a complete hot-added section
|
||||
* 3/ deactivation of a complete section from memory init
|
||||
*
|
||||
* For 1/, when subsection_map does not empty we will not be
|
||||
* freeing the usage map, but still need to free the vmemmap
|
||||
* range.
|
||||
*
|
||||
* For 2/ and 3/ the SPARSEMEM_VMEMMAP={y,n} cases are unified
|
||||
*/
|
||||
bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION);
|
||||
if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) {
|
||||
unsigned long section_nr = pfn_to_section_nr(pfn);
|
||||
|
||||
if (!section_is_early) {
|
||||
kfree(ms->usage);
|
||||
ms->usage = NULL;
|
||||
}
|
||||
memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
|
||||
ms->section_mem_map = sparse_encode_mem_map(NULL, section_nr);
|
||||
}
|
||||
|
||||
if (section_is_early && memmap)
|
||||
free_map_bootmem(memmap);
|
||||
else
|
||||
depopulate_section_memmap(pfn, nr_pages, altmap);
|
||||
}
|
||||
|
||||
static struct page * __meminit section_activate(int nid, unsigned long pfn,
|
||||
unsigned long nr_pages, struct vmem_altmap *altmap)
|
||||
{
|
||||
DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
|
||||
struct mem_section *ms = __pfn_to_section(pfn);
|
||||
struct mem_section_usage *usage = NULL;
|
||||
unsigned long *subsection_map;
|
||||
struct page *memmap;
|
||||
int rc = 0;
|
||||
|
||||
subsection_mask_set(map, pfn, nr_pages);
|
||||
|
||||
if (!ms->usage) {
|
||||
usage = kzalloc(mem_section_usage_size(), GFP_KERNEL);
|
||||
if (!usage)
|
||||
return ERR_PTR(-ENOMEM);
|
||||
ms->usage = usage;
|
||||
}
|
||||
subsection_map = &ms->usage->subsection_map[0];
|
||||
|
||||
if (bitmap_empty(map, SUBSECTIONS_PER_SECTION))
|
||||
rc = -EINVAL;
|
||||
else if (bitmap_intersects(map, subsection_map, SUBSECTIONS_PER_SECTION))
|
||||
rc = -EEXIST;
|
||||
else
|
||||
bitmap_or(subsection_map, map, subsection_map,
|
||||
SUBSECTIONS_PER_SECTION);
|
||||
|
||||
if (rc) {
|
||||
if (usage)
|
||||
ms->usage = NULL;
|
||||
kfree(usage);
|
||||
return ERR_PTR(rc);
|
||||
}
|
||||
|
||||
/*
|
||||
* The early init code does not consider partially populated
|
||||
* initial sections, it simply assumes that memory will never be
|
||||
* referenced. If we hot-add memory into such a section then we
|
||||
* do not need to populate the memmap and can simply reuse what
|
||||
* is already there.
|
||||
*/
|
||||
if (nr_pages < PAGES_PER_SECTION && early_section(ms))
|
||||
return pfn_to_page(pfn);
|
||||
|
||||
memmap = populate_section_memmap(pfn, nr_pages, nid, altmap);
|
||||
if (!memmap) {
|
||||
section_deactivate(pfn, nr_pages, altmap);
|
||||
return ERR_PTR(-ENOMEM);
|
||||
}
|
||||
|
||||
return memmap;
|
||||
}
|
||||
|
||||
/**
|
||||
* sparse_add_one_section - add a memory section
|
||||
* sparse_add_section - add a memory section, or populate an existing one
|
||||
* @nid: The node to add section on
|
||||
* @start_pfn: start pfn of the memory range
|
||||
* @nr_pages: number of pfns to add in the section
|
||||
* @altmap: device page map
|
||||
*
|
||||
* This is only intended for hotplug.
|
||||
|
|
@ -732,51 +849,34 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn,
|
|||
unsigned long nr_pages, struct vmem_altmap *altmap)
|
||||
{
|
||||
unsigned long section_nr = pfn_to_section_nr(start_pfn);
|
||||
struct mem_section_usage *usage;
|
||||
struct mem_section *ms;
|
||||
struct page *memmap;
|
||||
int ret;
|
||||
|
||||
/*
|
||||
* no locking for this, because it does its own
|
||||
* plus, it does a kmalloc
|
||||
*/
|
||||
ret = sparse_index_init(section_nr, nid);
|
||||
if (ret < 0 && ret != -EEXIST)
|
||||
if (ret < 0)
|
||||
return ret;
|
||||
ret = 0;
|
||||
memmap = populate_section_memmap(start_pfn, PAGES_PER_SECTION, nid,
|
||||
altmap);
|
||||
if (!memmap)
|
||||
return -ENOMEM;
|
||||
usage = kzalloc(mem_section_usage_size(), GFP_KERNEL);
|
||||
if (!usage) {
|
||||
depopulate_section_memmap(start_pfn, PAGES_PER_SECTION, altmap);
|
||||
return -ENOMEM;
|
||||
}
|
||||
|
||||
ms = __pfn_to_section(start_pfn);
|
||||
if (ms->section_mem_map & SECTION_MARKED_PRESENT) {
|
||||
ret = -EEXIST;
|
||||
goto out;
|
||||
}
|
||||
memmap = section_activate(nid, start_pfn, nr_pages, altmap);
|
||||
if (IS_ERR(memmap))
|
||||
return PTR_ERR(memmap);
|
||||
|
||||
/*
|
||||
* Poison uninitialized struct pages in order to catch invalid flags
|
||||
* combinations.
|
||||
*/
|
||||
page_init_poison(memmap, sizeof(struct page) * PAGES_PER_SECTION);
|
||||
page_init_poison(pfn_to_page(start_pfn), sizeof(struct page) * nr_pages);
|
||||
|
||||
ms = __pfn_to_section(start_pfn);
|
||||
set_section_nid(section_nr, nid);
|
||||
section_mark_present(ms);
|
||||
sparse_init_one_section(ms, section_nr, memmap, usage, 0);
|
||||
|
||||
out:
|
||||
if (ret < 0) {
|
||||
kfree(usage);
|
||||
depopulate_section_memmap(start_pfn, PAGES_PER_SECTION, altmap);
|
||||
}
|
||||
return ret;
|
||||
/* Align memmap to section boundary in the subsection case */
|
||||
if (section_nr_to_pfn(section_nr) != start_pfn)
|
||||
memmap = pfn_to_kaddr(section_nr_to_pfn(section_nr));
|
||||
sparse_init_one_section(ms, section_nr, memmap, ms->usage, 0);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
#ifdef CONFIG_MEMORY_FAILURE
|
||||
|
|
@ -809,48 +909,12 @@ static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
|
|||
}
|
||||
#endif
|
||||
|
||||
static void free_section_usage(struct mem_section *ms, struct page *memmap,
|
||||
struct mem_section_usage *usage, unsigned long pfn,
|
||||
unsigned long nr_pages, struct vmem_altmap *altmap)
|
||||
{
|
||||
if (!usage)
|
||||
return;
|
||||
|
||||
/*
|
||||
* Check to see if allocation came from hot-plug-add
|
||||
*/
|
||||
if (!early_section(ms)) {
|
||||
kfree(usage);
|
||||
if (memmap)
|
||||
depopulate_section_memmap(pfn, nr_pages, altmap);
|
||||
return;
|
||||
}
|
||||
|
||||
/*
|
||||
* The usemap came from bootmem. This is packed with other usemaps
|
||||
* on the section which has pgdat at boot time. Just keep it as is now.
|
||||
*/
|
||||
|
||||
if (memmap)
|
||||
free_map_bootmem(memmap);
|
||||
}
|
||||
|
||||
void sparse_remove_one_section(struct mem_section *ms, unsigned long pfn,
|
||||
void sparse_remove_section(struct mem_section *ms, unsigned long pfn,
|
||||
unsigned long nr_pages, unsigned long map_offset,
|
||||
struct vmem_altmap *altmap)
|
||||
{
|
||||
struct page *memmap = NULL;
|
||||
struct mem_section_usage *usage = NULL;
|
||||
|
||||
if (ms->section_mem_map) {
|
||||
usage = ms->usage;
|
||||
memmap = sparse_decode_mem_map(ms->section_mem_map,
|
||||
__section_nr(ms));
|
||||
ms->section_mem_map = 0;
|
||||
ms->usage = NULL;
|
||||
}
|
||||
|
||||
clear_hwpoisoned_pages(memmap + map_offset, nr_pages - map_offset);
|
||||
free_section_usage(ms, memmap, usage, pfn, nr_pages, altmap);
|
||||
clear_hwpoisoned_pages(pfn_to_page(pfn) + map_offset,
|
||||
nr_pages - map_offset);
|
||||
section_deactivate(pfn, nr_pages, altmap);
|
||||
}
|
||||
#endif /* CONFIG_MEMORY_HOTPLUG */
|
||||
|
|
|
|||
Loading…
Reference in a new issue