From: Dan Williams <dan.j.williams@xxxxxxxxx> Subject: libnvdimm/pfn: stop padding pmem namespaces to section alignment 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. Link: http://lkml.kernel.org/r/156092356588.979959.6793371748950931916.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> Reported-by: Jeff Moyer <jmoyer@xxxxxxxxxx> Tested-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> [ppc64] Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Jane Chu <jane.chu@xxxxxxxxxx> Cc: Jérôme Glisse <jglisse@xxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxx> Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> Cc: Toshi Kani <toshi.kani@xxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx> Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/nvdimm/pfn.h | 14 ------ drivers/nvdimm/pfn_devs.c | 77 ++++++------------------------------ include/linux/mmzone.h | 3 + 3 files changed, 16 insertions(+), 78 deletions(-) --- a/drivers/nvdimm/pfn_devs.c~libnvdimm-pfn-stop-padding-pmem-namespaces-to-section-alignment +++ a/drivers/nvdimm/pfn_devs.c @@ -587,14 +587,14 @@ static u32 info_block_reserve(void) } /* - * We hotplug memory at section granularity, pad the reserved area from - * the previous section base to the namespace base address. + * We hotplug memory at sub-section granularity, pad the reserved area + * from the previous section base to the namespace base address. */ static unsigned long init_altmap_base(resource_size_t base) { unsigned long base_pfn = PHYS_PFN(base); - return PFN_SECTION_ALIGN_DOWN(base_pfn); + return SUBSECTION_ALIGN_DOWN(base_pfn); } static unsigned long init_altmap_reserve(resource_size_t base) @@ -602,7 +602,7 @@ static unsigned long init_altmap_reserve unsigned long reserve = info_block_reserve() >> PAGE_SHIFT; unsigned long base_pfn = PHYS_PFN(base); - reserve += base_pfn - PFN_SECTION_ALIGN_DOWN(base_pfn); + reserve += base_pfn - SUBSECTION_ALIGN_DOWN(base_pfn); return reserve; } @@ -632,8 +632,7 @@ static int __nvdimm_setup_pfn(struct nd_ return -EINVAL; nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns); } else if (nd_pfn->mode == PFN_MODE_PMEM) { - nd_pfn->npfns = PFN_SECTION_ALIGN_UP((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", @@ -649,54 +648,14 @@ static int __nvdimm_setup_pfn(struct nd_ return 0; } -static u64 phys_pmem_align_down(struct nd_pfn *nd_pfn, u64 phys) -{ - return min_t(u64, PHYS_SECTION_ALIGN_DOWN(phys), - ALIGN_DOWN(phys, nd_pfn->align)); -} - -/* - * Check if pmem collides with 'System RAM', or other regions when - * section aligned. Trim it accordingly. - */ -static void trim_pfn_device(struct nd_pfn *nd_pfn, u32 *start_pad, u32 *end_trunc) -{ - struct nd_namespace_common *ndns = nd_pfn->ndns; - struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev); - struct nd_region *nd_region = to_nd_region(nd_pfn->dev.parent); - const resource_size_t start = nsio->res.start; - const resource_size_t end = start + resource_size(&nsio->res); - resource_size_t adjust, size; - - *start_pad = 0; - *end_trunc = 0; - - adjust = start - PHYS_SECTION_ALIGN_DOWN(start); - size = resource_size(&nsio->res) + adjust; - if (region_intersects(start - adjust, size, IORESOURCE_SYSTEM_RAM, - IORES_DESC_NONE) == REGION_MIXED - || nd_region_conflict(nd_region, start - adjust, size)) - *start_pad = PHYS_SECTION_ALIGN_UP(start) - start; - - /* Now check that end of the range does not collide. */ - adjust = PHYS_SECTION_ALIGN_UP(end) - end; - size = resource_size(&nsio->res) + adjust; - if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM, - IORES_DESC_NONE) == REGION_MIXED - || !IS_ALIGNED(end, nd_pfn->align) - || nd_region_conflict(nd_region, start, size)) - *end_trunc = end - phys_pmem_align_down(nd_pfn, end); -} - static int nd_pfn_init(struct nd_pfn *nd_pfn) { struct nd_namespace_common *ndns = nd_pfn->ndns; struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev); - u32 start_pad, end_trunc, reserve = info_block_reserve(); resource_size_t start, size; struct nd_region *nd_region; + unsigned long npfns, align; struct nd_pfn_sb *pfn_sb; - unsigned long npfns; phys_addr_t offset; const char *sig; u64 checksum; @@ -727,43 +686,35 @@ static int nd_pfn_init(struct nd_pfn *nd return -ENXIO; } - memset(pfn_sb, 0, sizeof(*pfn_sb)); - - trim_pfn_device(nd_pfn, &start_pad, &end_trunc); - if (start_pad + end_trunc) - dev_info(&nd_pfn->dev, "%s alignment 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 = nsio->res.start + start_pad; + start = nsio->res.start; size = resource_size(&nsio->res); - npfns = PFN_SECTION_ALIGN_UP((size - start_pad - end_trunc - reserve) - / PAGE_SIZE); + npfns = PHYS_PFN(size - SZ_8K); + align = max(nd_pfn->align, (1UL << SUBSECTION_SHIFT)); if (nd_pfn->mode == PFN_MODE_PMEM) { /* * The altmap should be padded out to the block size used * when populating the vmemmap. This *should* be equal to * PMD_SIZE for most architectures. */ - offset = ALIGN(start + reserve + 64 * npfns, - max(nd_pfn->align, PMD_SIZE)) - start; + offset = ALIGN(start + SZ_8K + 64 * npfns, align) - start; } else if (nd_pfn->mode == PFN_MODE_RAM) - offset = ALIGN(start + reserve, nd_pfn->align) - start; + offset = ALIGN(start + SZ_8K, align) - start; 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; + 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); @@ -772,8 +723,6 @@ static int nd_pfn_init(struct nd_pfn *nd 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(3); - 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); --- a/drivers/nvdimm/pfn.h~libnvdimm-pfn-stop-padding-pmem-namespaces-to-section-alignment +++ a/drivers/nvdimm/pfn.h @@ -33,18 +33,4 @@ struct nd_pfn_sb { __le64 checksum; }; -#ifdef CONFIG_SPARSEMEM -#define PFN_SECTION_ALIGN_DOWN(x) SECTION_ALIGN_DOWN(x) -#define PFN_SECTION_ALIGN_UP(x) SECTION_ALIGN_UP(x) -#else -/* - * In this case ZONE_DEVICE=n and we will disable 'pfn' device support, - * but we still want pmem to compile. - */ -#define PFN_SECTION_ALIGN_DOWN(x) (x) -#define PFN_SECTION_ALIGN_UP(x) (x) -#endif - -#define PHYS_SECTION_ALIGN_DOWN(x) PFN_PHYS(PFN_SECTION_ALIGN_DOWN(PHYS_PFN(x))) -#define PHYS_SECTION_ALIGN_UP(x) PFN_PHYS(PFN_SECTION_ALIGN_UP(PHYS_PFN(x))) #endif /* __NVDIMM_PFN_H */ --- a/include/linux/mmzone.h~libnvdimm-pfn-stop-padding-pmem-namespaces-to-section-alignment +++ a/include/linux/mmzone.h @@ -1160,6 +1160,9 @@ static inline unsigned long section_nr_t #define SUBSECTIONS_PER_SECTION (1UL << (SECTION_SIZE_BITS - SUBSECTION_SHIFT)) #endif +#define SUBSECTION_ALIGN_UP(pfn) ALIGN((pfn), PAGES_PER_SUBSECTION) +#define SUBSECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SUBSECTION_MASK) + struct mem_section_usage { DECLARE_BITMAP(subsection_map, SUBSECTIONS_PER_SECTION); /* See declaration of similar field in struct zone */ _
