Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1539038 > unrolled thread

[PATCH v2 00/11] mm: sub-section memory hotplug support

Started byDan Williams <dan.j.williams@intel.com>
First post2016-12-09 03:50 +0100
Last post2016-12-09 03:50 +0100
Articles 4 — 1 participant

Back to article view | Back to linux.kernel

Contents

  [PATCH v2 00/11] mm: sub-section memory hotplug support Dan Williams <dan.j.williams@intel.com> - 2016-12-09 03:50 +0100
    [PATCH v2 02/11] mm: introduce struct mem_section_usage to track  partial population of a section Dan Williams <dan.j.williams@intel.com> - 2016-12-09 03:50 +0100
    [PATCH v2 11/11] libnvdimm, pfn,  dax: stop padding pmem namespaces to section alignment Dan Williams <dan.j.williams@intel.com> - 2016-12-09 03:50 +0100
    [PATCH v2 04/11] mm: cleanup sparse_init_one_section() return value Dan Williams <dan.j.williams@intel.com> - 2016-12-09 03:50 +0100

#1539038 — [PATCH v2 00/11] mm: sub-section memory hotplug support

FromDan Williams <dan.j.williams@intel.com>
Date2016-12-09 03:50 +0100
Subject[PATCH v2 00/11] mm: sub-section memory hotplug support
Message-ID<sMjq1-5Sr-3@gated-at.bofh.it>
Changes since v1 [1]:

1/ fixed the pgmap_radix to index pfns instead of full physical
   addresses

2/ reflowed the follow-on patches and fixed a conflict in patch 10, but
   no other functional changes.

[1]: https://lkml.org/lkml/2016/12/1/740

---

Same cover letter from v1:

Quoting "[PATCH 09/11] mm: support section-unaligned ZONE_DEVICE memory
ranges":

---

The initial motivation for this change is persistent memory platforms
that, unfortunately, align the pmem range on a boundary less than a full
section (64M vs 128M), and may change the alignment from one boot to the
next. A secondary motivation is the arrival of prospective ZONE_DEVICE
users that want devm_memremap_pages() to map PCI-E device memory ranges
to enable peer-to-peer DMA.

Currently the nvdimm core injects padding when 'pfn' (struct page
mapping configuration) instances are created. However, not all users of
devm_memremap_pages() have the opportunity to inject such padding. Users
of the memmap=ss!nn kernel command line option can trigger the following
failure with unaligned parameters like "memmap=0xfc000000!8G":

 WARNING: CPU: 0 PID: 558 at kernel/memremap.c:300 devm_memremap_pages+0x3b5/0x4c0
 devm_memremap_pages attempted on mixed region [mem 0x200000000-0x2fbffffff flags 0x200]
 [..]
 Call Trace:
  [<ffffffff814c0393>] dump_stack+0x86/0xc3
  [<ffffffff810b173b>] __warn+0xcb/0xf0
  [<ffffffff810b17bf>] warn_slowpath_fmt+0x5f/0x80
  [<ffffffff811eb105>] devm_memremap_pages+0x3b5/0x4c0
  [<ffffffffa006f308>] __wrap_devm_memremap_pages+0x58/0x70 [nfit_test_iomap]
  [<ffffffffa00e231a>] pmem_attach_disk+0x19a/0x440 [nd_pmem]

Without this change a user could inadvertently lose access to nvdimm
namespaces by adding/removing other DIMMs in the platform leading to the
BIOS changing the base alignment of the namespace in an incompatible
fashion. With this support we can accommodate a BIOS changing the
namespace to any alignment provided it is >= SECTION_ACTIVE_SIZE.

---

Andrew, yes, this is rather late for 4.10, but it is ostensibly a fix
for devm_memremap_pages(). Both the memmap=ss!nn and qemu-kvm methods of
defining persistent memory can generate the misaligned configuration.
However, in those cases the existing devm_memremap_pages() would have
failed so no one could be relying on that.

The greater concern is new misalignment injected by the BIOS after the
libnvdimm sub-system already recorded that the namespace does not need
alignment padding. In that case the user would need to figure out how to
undo the BIOS change to regain access to their nvdimm device.

The patches have received a build success notification from the
0day-kbuild robot across 177 configs and pass the ndctl unit test suite.
They merge cleanly on top of current -next (test merge with
next-20161201).

---

New diffstat:

Dan Williams (11):
      mm, devm_memremap_pages: use multi-order radix for ZONE_DEVICE lookups
      mm: introduce struct mem_section_usage to track partial population of a section
      mm: introduce common definitions for the size and mask of a section
      mm: cleanup sparse_init_one_section() return value
      mm: track active portions of a section at boot
      mm: fix register_new_memory() zone type detection
      mm: convert kmalloc_section_memmap() to populate_section_memmap()
      mm: prepare for hot-{add,remove} of sub-section ranges
      mm: support section-unaligned ZONE_DEVICE memory ranges
      mm: enable section-unaligned devm_memremap_pages()
      libnvdimm, pfn, dax: stop padding pmem namespaces to section alignment


 arch/x86/mm/init_64.c          |   15 +
 drivers/base/memory.c          |   26 +-
 drivers/nvdimm/pfn_devs.c      |   42 +---
 include/linux/memory.h         |    4 
 include/linux/memory_hotplug.h |    6 -
 include/linux/mm.h             |    3 
 include/linux/mmzone.h         |   26 ++
 kernel/memremap.c              |   75 ++++---
 mm/Kconfig                     |    1 
 mm/memory_hotplug.c            |   95 ++++----
 mm/page_alloc.c                |    6 -
 mm/sparse-vmemmap.c            |   24 +-
 mm/sparse.c                    |  454 +++++++++++++++++++++++++++++-----------
 13 files changed, 510 insertions(+), 267 deletions(-)

[toc] | [next] | [standalone]

#1539039 — [PATCH v2 02/11] mm: introduce struct mem_section_usage to track partial population of a section

FromDan Williams <dan.j.williams@intel.com>
Date2016-12-09 03:50 +0100
Subject[PATCH v2 02/11] mm: introduce struct mem_section_usage to track partial population of a section
Message-ID<sMjq2-5Sr-43@gated-at.bofh.it>
In reply to#1539038
'struct mem_section_usage' combines the existing 'pageblock_flags' bitmap
with a new 'map_active' bitmap.  The new bitmap enables the memory
hot{plug,remove} implementation to act on incremental sub-divisions of
a section. The primary impetus for this functionality is to support
platforms that mix "System RAM" and "Persistent Memory" within a single
section.  We want to be able to hotplug "Persistent Memory" to extend a
partially populated section and share that section between ZONE_DEVICE and
ZONE_NORMAL/MOVABLE memory.

This introduces a pointer to the new 'map_active' bitmap through struct
mem_section, but otherwise should not change any behavior.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Stephen Bates <stephen.bates@microsemi.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 include/linux/mmzone.h |   21 +++++++++-
 mm/memory_hotplug.c    |    4 +-
 mm/page_alloc.c        |    2 -
 mm/sparse.c            |   98 ++++++++++++++++++++++++++----------------------
 4 files changed, 75 insertions(+), 50 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 0f088f3a2fed..b13b490321a5 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1068,6 +1068,19 @@ static inline unsigned long early_pfn_to_nid(unsigned long pfn)
 #define SECTION_ALIGN_UP(pfn)	(((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK)
 #define SECTION_ALIGN_DOWN(pfn)	((pfn) & PAGE_SECTION_MASK)
 
+#define SECTION_ACTIVE_SIZE ((1UL << SECTION_SIZE_BITS) / BITS_PER_LONG)
+#define SECTION_ACTIVE_MASK (~(SECTION_ACTIVE_SIZE - 1))
+
+struct mem_section_usage {
+	/*
+	 * SECTION_ACTIVE_SIZE portions of the section that are populated in
+	 * the memmap
+	 */
+	unsigned long map_active;
+	/* See declaration of similar field in struct zone */
+	unsigned long pageblock_flags[0];
+};
+
 struct page;
 struct page_ext;
 struct mem_section {
@@ -1085,8 +1098,7 @@ struct mem_section {
 	 */
 	unsigned long section_mem_map;
 
-	/* See declaration of similar field in struct zone */
-	unsigned long *pageblock_flags;
+	struct mem_section_usage *usage;
 #ifdef CONFIG_PAGE_EXTENSION
 	/*
 	 * If SPARSEMEM, pgdat doesn't have page_ext pointer. We use
@@ -1117,6 +1129,11 @@ extern struct mem_section *mem_section[NR_SECTION_ROOTS];
 extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
 #endif
 
+static inline unsigned long *section_to_usemap(struct mem_section *ms)
+{
+	return ms->usage->pageblock_flags;
+}
+
 static inline struct mem_section *__nr_to_section(unsigned long nr)
 {
 	if (!mem_section[SECTION_NR_TO_ROOT(nr)])
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index cad4b9125695..c7b3b2308ac3 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -227,7 +227,7 @@ static void register_page_bootmem_info_section(unsigned long start_pfn)
 	for (i = 0; i < mapsize; i++, page++)
 		get_page_bootmem(section_nr, page, SECTION_INFO);
 
-	usemap = __nr_to_section(section_nr)->pageblock_flags;
+	usemap = section_to_usemap(__nr_to_section(section_nr));
 	page = virt_to_page(usemap);
 
 	mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
@@ -253,7 +253,7 @@ static void register_page_bootmem_info_section(unsigned long start_pfn)
 
 	register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
 
-	usemap = __nr_to_section(section_nr)->pageblock_flags;
+	usemap = section_to_usemap(__nr_to_section(section_nr));
 	page = virt_to_page(usemap);
 
 	mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8fd42aa7c4bd..8a509e382f55 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -352,7 +352,7 @@ static inline unsigned long *get_pageblock_bitmap(struct page *page,
 							unsigned long pfn)
 {
 #ifdef CONFIG_SPARSEMEM
-	return __pfn_to_section(pfn)->pageblock_flags;
+	return section_to_usemap(__pfn_to_section(pfn));
 #else
 	return page_zone(page)->pageblock_flags;
 #endif /* CONFIG_SPARSEMEM */
diff --git a/mm/sparse.c b/mm/sparse.c
index 1e168bf2779a..91e1908db23d 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -233,15 +233,15 @@ struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pn
 
 static int __meminit sparse_init_one_section(struct mem_section *ms,
 		unsigned long pnum, struct page *mem_map,
-		unsigned long *pageblock_bitmap)
+		struct mem_section_usage *usage)
 {
 	if (!present_section(ms))
 		return -EINVAL;
 
 	ms->section_mem_map &= ~SECTION_MAP_MASK;
 	ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) |
-							SECTION_HAS_MEM_MAP;
- 	ms->pageblock_flags = pageblock_bitmap;
+		SECTION_HAS_MEM_MAP;
+	ms->usage = usage;
 
 	return 1;
 }
@@ -255,9 +255,13 @@ unsigned long usemap_size(void)
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
-static unsigned long *__kmalloc_section_usemap(void)
+static struct mem_section_usage *__alloc_section_usage(void)
 {
-	return kmalloc(usemap_size(), GFP_KERNEL);
+	struct mem_section_usage *usage;
+
+	usage = kzalloc(sizeof(*usage) + usemap_size(), GFP_KERNEL);
+	/* TODO: allocate the map_active bitmap */
+	return usage;
 }
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
@@ -293,7 +297,8 @@ sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 	return p;
 }
 
-static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
+static void __init check_usemap_section_nr(int nid,
+		struct mem_section_usage *usage)
 {
 	unsigned long usemap_snr, pgdat_snr;
 	static unsigned long old_usemap_snr = NR_MEM_SECTIONS;
@@ -301,7 +306,7 @@ static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 	struct pglist_data *pgdat = NODE_DATA(nid);
 	int usemap_nid;
 
-	usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT);
+	usemap_snr = pfn_to_section_nr(__pa(usage) >> PAGE_SHIFT);
 	pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
 	if (usemap_snr == pgdat_snr)
 		return;
@@ -336,7 +341,8 @@ sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 	return memblock_virt_alloc_node_nopanic(size, pgdat->node_id);
 }
 
-static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
+static void __init check_usemap_section_nr(int nid,
+		struct mem_section_usage *usage)
 {
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
@@ -344,26 +350,27 @@ static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 static void __init sparse_early_usemaps_alloc_node(void *data,
 				 unsigned long pnum_begin,
 				 unsigned long pnum_end,
-				 unsigned long usemap_count, int nodeid)
+				 unsigned long usage_count, int nodeid)
 {
-	void *usemap;
+	void *usage;
 	unsigned long pnum;
-	unsigned long **usemap_map = (unsigned long **)data;
-	int size = usemap_size();
+	struct mem_section_usage **usage_map = data;
+	int size = sizeof(struct mem_section_usage) + usemap_size();
 
-	usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nodeid),
-							  size * usemap_count);
-	if (!usemap) {
+	usage = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nodeid),
+							  size * usage_count);
+	if (!usage) {
 		pr_warn("%s: allocation failed\n", __func__);
 		return;
 	}
 
+	memset(usage, 0, size * usage_count);
 	for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 		if (!present_section_nr(pnum))
 			continue;
-		usemap_map[pnum] = usemap;
-		usemap += size;
-		check_usemap_section_nr(nodeid, usemap_map[pnum]);
+		usage_map[pnum] = usage;
+		usage += size;
+		check_usemap_section_nr(nodeid, usage_map[pnum]);
 	}
 }
 
@@ -468,7 +475,7 @@ void __weak __meminit vmemmap_populate_print_last(void)
 
 /**
  *  alloc_usemap_and_memmap - memory alloction for pageblock flags and vmemmap
- *  @map: usemap_map for pageblock flags or mmap_map for vmemmap
+ *  @map: usage_map for mem_section_usage or mmap_map for vmemmap
  */
 static void __init alloc_usemap_and_memmap(void (*alloc_func)
 					(void *, unsigned long, unsigned long,
@@ -521,10 +528,9 @@ static void __init alloc_usemap_and_memmap(void (*alloc_func)
  */
 void __init sparse_init(void)
 {
+	struct mem_section_usage *usage, **usage_map;
 	unsigned long pnum;
 	struct page *map;
-	unsigned long *usemap;
-	unsigned long **usemap_map;
 	int size;
 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 	int size2;
@@ -539,21 +545,21 @@ void __init sparse_init(void)
 
 	/*
 	 * map is using big page (aka 2M in x86 64 bit)
-	 * usemap is less one page (aka 24 bytes)
+	 * usage is less one page (aka 24 bytes)
 	 * so alloc 2M (with 2M align) and 24 bytes in turn will
 	 * make next 2M slip to one more 2M later.
 	 * then in big system, the memory will have a lot of holes...
 	 * here try to allocate 2M pages continuously.
 	 *
 	 * powerpc need to call sparse_init_one_section right after each
-	 * sparse_early_mem_map_alloc, so allocate usemap_map at first.
+	 * sparse_early_mem_map_alloc, so allocate usage_map at first.
 	 */
-	size = sizeof(unsigned long *) * NR_MEM_SECTIONS;
-	usemap_map = memblock_virt_alloc(size, 0);
-	if (!usemap_map)
-		panic("can not allocate usemap_map\n");
+	size = sizeof(struct mem_section_usage *) * NR_MEM_SECTIONS;
+	usage_map = memblock_virt_alloc(size, 0);
+	if (!usage_map)
+		panic("can not allocate usage_map\n");
 	alloc_usemap_and_memmap(sparse_early_usemaps_alloc_node,
-							(void *)usemap_map);
+							(void *)usage_map);
 
 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 	size2 = sizeof(struct page *) * NR_MEM_SECTIONS;
@@ -568,8 +574,8 @@ void __init sparse_init(void)
 		if (!present_section_nr(pnum))
 			continue;
 
-		usemap = usemap_map[pnum];
-		if (!usemap)
+		usage = usage_map[pnum];
+		if (!usage)
 			continue;
 
 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
@@ -581,7 +587,7 @@ void __init sparse_init(void)
 			continue;
 
 		sparse_init_one_section(__nr_to_section(pnum), pnum, map,
-								usemap);
+								usage);
 	}
 
 	vmemmap_populate_print_last();
@@ -589,7 +595,7 @@ void __init sparse_init(void)
 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 	memblock_free_early(__pa(map_map), size2);
 #endif
-	memblock_free_early(__pa(usemap_map), size);
+	memblock_free_early(__pa(usage_map), size);
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
@@ -693,9 +699,9 @@ int __meminit sparse_add_one_section(struct zone *zone, unsigned long start_pfn)
 {
 	unsigned long section_nr = pfn_to_section_nr(start_pfn);
 	struct pglist_data *pgdat = zone->zone_pgdat;
+	static struct mem_section_usage *usage;
 	struct mem_section *ms;
 	struct page *memmap;
-	unsigned long *usemap;
 	unsigned long flags;
 	int ret;
 
@@ -709,8 +715,8 @@ int __meminit sparse_add_one_section(struct zone *zone, unsigned long start_pfn)
 	memmap = kmalloc_section_memmap(section_nr, pgdat->node_id);
 	if (!memmap)
 		return -ENOMEM;
-	usemap = __kmalloc_section_usemap();
-	if (!usemap) {
+	usage = __alloc_section_usage();
+	if (!usage) {
 		__kfree_section_memmap(memmap);
 		return -ENOMEM;
 	}
@@ -727,12 +733,12 @@ int __meminit sparse_add_one_section(struct zone *zone, unsigned long start_pfn)
 
 	ms->section_mem_map |= SECTION_MARKED_PRESENT;
 
-	ret = sparse_init_one_section(ms, section_nr, memmap, usemap);
+	ret = sparse_init_one_section(ms, section_nr, memmap, usage);
 
 out:
 	pgdat_resize_unlock(pgdat, &flags);
 	if (ret <= 0) {
-		kfree(usemap);
+		kfree(usage);
 		__kfree_section_memmap(memmap);
 	}
 	return ret;
@@ -760,19 +766,20 @@ static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 }
 #endif
 
-static void free_section_usemap(struct page *memmap, unsigned long *usemap)
+static void free_section_usage(struct page *memmap,
+		struct mem_section_usage *usage)
 {
 	struct page *usemap_page;
 
-	if (!usemap)
+	if (!usage)
 		return;
 
-	usemap_page = virt_to_page(usemap);
+	usemap_page = virt_to_page(usage->pageblock_flags);
 	/*
 	 * Check to see if allocation came from hot-plug-add
 	 */
 	if (PageSlab(usemap_page) || PageCompound(usemap_page)) {
-		kfree(usemap);
+		kfree(usage);
 		if (memmap)
 			__kfree_section_memmap(memmap);
 		return;
@@ -790,23 +797,24 @@ static void free_section_usemap(struct page *memmap, unsigned long *usemap)
 void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
 		unsigned long map_offset)
 {
+	unsigned long flags;
 	struct page *memmap = NULL;
-	unsigned long *usemap = NULL, flags;
+	struct mem_section_usage *usage = NULL;
 	struct pglist_data *pgdat = zone->zone_pgdat;
 
 	pgdat_resize_lock(pgdat, &flags);
 	if (ms->section_mem_map) {
-		usemap = ms->pageblock_flags;
+		usage = ms->usage;
 		memmap = sparse_decode_mem_map(ms->section_mem_map,
 						__section_nr(ms));
 		ms->section_mem_map = 0;
-		ms->pageblock_flags = NULL;
+		ms->usage = NULL;
 	}
 	pgdat_resize_unlock(pgdat, &flags);
 
 	clear_hwpoisoned_pages(memmap + map_offset,
 			PAGES_PER_SECTION - map_offset);
-	free_section_usemap(memmap, usemap);
+	free_section_usage(memmap, usage);
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 #endif /* CONFIG_MEMORY_HOTPLUG */

[toc] | [prev] | [next] | [standalone]

#1539040 — [PATCH v2 11/11] libnvdimm, pfn, dax: stop padding pmem namespaces to section alignment

FromDan Williams <dan.j.williams@intel.com>
Date2016-12-09 03:50 +0100
Subject[PATCH v2 11/11] libnvdimm, pfn, dax: stop padding pmem namespaces to section alignment
Message-ID<sMjq3-5Sr-47@gated-at.bofh.it>
In reply to#1539038
Now that the mm core supports section-unaligned hotplug of ZONE_DEVICE
memory, we no longer need to add padding at pfn/dax device creation
time. The kernel will still honor padding established by older kernels.

Cc: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/nvdimm/pfn_devs.c |   42 +++++++-----------------------------------
 1 file changed, 7 insertions(+), 35 deletions(-)

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index cea8350fbc7e..ead3c3186d09 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -538,7 +538,7 @@ static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 		nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
 		altmap = NULL;
 	} else if (nd_pfn->mode == PFN_MODE_PMEM) {
-		nd_pfn->npfns = (resource_size(res) - offset) / PAGE_SIZE;
+		nd_pfn->npfns = PHYS_PFN((resource_size(res) - offset));
 		if (le64_to_cpu(nd_pfn->pfn_sb->npfns) > nd_pfn->npfns)
 			dev_info(&nd_pfn->dev,
 					"number of pfns truncated from %lld to %ld\n",
@@ -557,7 +557,6 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
 {
 	u32 dax_label_reserve = is_nd_dax(&nd_pfn->dev) ? SZ_128K : 0;
 	struct nd_namespace_common *ndns = nd_pfn->ndns;
-	u32 start_pad = 0, end_trunc = 0;
 	resource_size_t start, size;
 	struct nd_namespace_io *nsio;
 	struct nd_region *nd_region;
@@ -590,42 +589,16 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
 		return -ENXIO;
 	}
 
-	memset(pfn_sb, 0, sizeof(*pfn_sb));
-
-	/*
-	 * Check if pmem collides with 'System RAM' when section aligned and
-	 * trim it accordingly
-	 */
-	nsio = to_nd_namespace_io(&ndns->dev);
-	start = PHYS_SECTION_ALIGN_DOWN(nsio->res.start);
-	size = resource_size(&nsio->res);
-	if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
-				IORES_DESC_NONE) == REGION_MIXED) {
-		start = nsio->res.start;
-		start_pad = PHYS_SECTION_ALIGN_UP(start) - start;
-	}
-
-	start = nsio->res.start;
-	size = PHYS_SECTION_ALIGN_UP(start + size) - start;
-	if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
-				IORES_DESC_NONE) == REGION_MIXED) {
-		size = resource_size(&nsio->res);
-		end_trunc = start + size - PHYS_SECTION_ALIGN_DOWN(start + size);
-	}
-
-	if (start_pad + end_trunc)
-		dev_info(&nd_pfn->dev, "%s section collision, truncate %d bytes\n",
-				dev_name(&ndns->dev), start_pad + end_trunc);
-
 	/*
 	 * Note, we use 64 here for the standard size of struct page,
 	 * debugging options may cause it to be larger in which case the
 	 * implementation will limit the pfns advertised through
 	 * ->direct_access() to those that are included in the memmap.
 	 */
-	start += start_pad;
+	nsio = to_nd_namespace_io(&ndns->dev);
+	start = nsio->res.start;
 	size = resource_size(&nsio->res);
-	npfns = (size - start_pad - end_trunc - SZ_8K) / SZ_4K;
+	npfns = PHYS_PFN(size - SZ_8K);
 	if (nd_pfn->mode == PFN_MODE_PMEM) {
 		unsigned long memmap_size;
 
@@ -642,13 +615,14 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
 	else
 		return -ENXIO;
 
-	if (offset + start_pad + end_trunc >= size) {
+	if (offset >= size) {
 		dev_err(&nd_pfn->dev, "%s unable to satisfy requested alignment\n",
 				dev_name(&ndns->dev));
 		return -ENXIO;
 	}
 
-	npfns = (size - offset - start_pad - end_trunc) / SZ_4K;
+	memset(pfn_sb, 0, sizeof(*pfn_sb));
+	npfns = PHYS_PFN(size - offset);
 	pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
 	pfn_sb->dataoff = cpu_to_le64(offset);
 	pfn_sb->npfns = cpu_to_le64(npfns);
@@ -657,8 +631,6 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
 	memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
 	pfn_sb->version_major = cpu_to_le16(1);
 	pfn_sb->version_minor = cpu_to_le16(2);
-	pfn_sb->start_pad = cpu_to_le32(start_pad);
-	pfn_sb->end_trunc = cpu_to_le32(end_trunc);
 	pfn_sb->align = cpu_to_le32(nd_pfn->align);
 	checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
 	pfn_sb->checksum = cpu_to_le64(checksum);

[toc] | [prev] | [next] | [standalone]

#1539041 — [PATCH v2 04/11] mm: cleanup sparse_init_one_section() return value

FromDan Williams <dan.j.williams@intel.com>
Date2016-12-09 03:50 +0100
Subject[PATCH v2 04/11] mm: cleanup sparse_init_one_section() return value
Message-ID<sMjq3-5Sr-49@gated-at.bofh.it>
In reply to#1539038
We mark and check that the section is present under a spin_lock() in
sparse_add_one_section(), so the lock ensures it will not change between
those 2 events. Also, we do not check the -EBUSY return value in
sparse_init(). Just make sparse_init_one_section() return void and clean
up the error handling.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Stephen Bates <stephen.bates@microsemi.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 mm/sparse.c |   21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index 91e1908db23d..59966a3e8ff0 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -231,19 +231,14 @@ struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pn
 	return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
 }
 
-static int __meminit sparse_init_one_section(struct mem_section *ms,
+static void __meminit sparse_init_one_section(struct mem_section *ms,
 		unsigned long pnum, struct page *mem_map,
 		struct mem_section_usage *usage)
 {
-	if (!present_section(ms))
-		return -EINVAL;
-
 	ms->section_mem_map &= ~SECTION_MAP_MASK;
 	ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) |
 		SECTION_HAS_MEM_MAP;
 	ms->usage = usage;
-
-	return 1;
 }
 
 unsigned long usemap_size(void)
@@ -690,11 +685,6 @@ static void free_map_bootmem(struct page *memmap)
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 
-/*
- * returns the number of sections whose mem_maps were properly
- * set.  If this is <=0, then that means that the passed-in
- * map was not consumed and must be freed.
- */
 int __meminit sparse_add_one_section(struct zone *zone, unsigned long start_pfn)
 {
 	unsigned long section_nr = pfn_to_section_nr(start_pfn);
@@ -725,7 +715,7 @@ int __meminit sparse_add_one_section(struct zone *zone, unsigned long start_pfn)
 
 	ms = __pfn_to_section(start_pfn);
 	if (ms->section_mem_map & SECTION_MARKED_PRESENT) {
-		ret = -EEXIST;
+		ret = -EBUSY;
 		goto out;
 	}
 
@@ -733,15 +723,16 @@ int __meminit sparse_add_one_section(struct zone *zone, unsigned long start_pfn)
 
 	ms->section_mem_map |= SECTION_MARKED_PRESENT;
 
-	ret = sparse_init_one_section(ms, section_nr, memmap, usage);
+	sparse_init_one_section(ms, section_nr, memmap, usage);
 
 out:
 	pgdat_resize_unlock(pgdat, &flags);
-	if (ret <= 0) {
+	if (ret < 0 && ret != -EEXIST) {
 		kfree(usage);
 		__kfree_section_memmap(memmap);
+		return ret;
 	}
-	return ret;
+	return 0;
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web