Currently libnvdimm uses HPAGE_SIZE as the default alignment for DAX and PFN devices. HPAGE_SIZE is the default hugetlbfs page size and when hugetlbfs is disabled it defaults to PAGE_SIZE. Given DAX has more in common with THP than hugetlbfs we should proably be using HPAGE_PMD_SIZE, but this is undefined when THP is disabled so lets just give it a new name.
The other usage of HPAGE_SIZE in libnvdimm is when determining how large the altmap should be. For the reasons mentioned above it doesn't really make sense to use HPAGE_SIZE here either. PMD_SIZE seems to be safe to use in generic code and it happens to match the vmemmap allocation block on x86 and Power. It's still a hack, but it's a slightly nicer hack. Signed-off-by: Oliver O'Halloran <[email protected]> --- drivers/nvdimm/nd.h | 7 +++++++ drivers/nvdimm/pfn_devs.c | 9 +++++---- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h index 8cabd836df0e..714e3337b609 100644 --- a/drivers/nvdimm/nd.h +++ b/drivers/nvdimm/nd.h @@ -281,6 +281,13 @@ static inline struct device *nd_btt_create(struct nd_region *nd_region) struct nd_pfn *to_nd_pfn(struct device *dev); #if IS_ENABLED(CONFIG_NVDIMM_PFN) + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#define PFN_DEFAULT_ALIGNMENT HPAGE_PMD_SIZE +#else +#define PFN_DEFAULT_ALIGNMENT PAGE_SIZE +#endif + int nd_pfn_probe(struct device *dev, struct nd_namespace_common *ndns); bool is_nd_pfn(struct device *dev); struct device *nd_pfn_create(struct nd_region *nd_region); diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c index 5fcb6f5b22a2..2ae9a000b090 100644 --- a/drivers/nvdimm/pfn_devs.c +++ b/drivers/nvdimm/pfn_devs.c @@ -290,7 +290,7 @@ struct device *nd_pfn_devinit(struct nd_pfn *nd_pfn, return NULL; nd_pfn->mode = PFN_MODE_NONE; - nd_pfn->align = HPAGE_SIZE; + nd_pfn->align = PFN_DEFAULT_ALIGNMENT; dev = &nd_pfn->dev; device_initialize(&nd_pfn->dev); if (ndns && !__nd_attach_ndns(&nd_pfn->dev, ndns, &nd_pfn->ndns)) { @@ -638,11 +638,12 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn) / PAGE_SIZE); if (nd_pfn->mode == PFN_MODE_PMEM) { /* - * vmemmap_populate_hugepages() allocates the memmap array in - * HPAGE_SIZE chunks. + * 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 + SZ_8K + 64 * npfns + dax_label_reserve, - max(nd_pfn->align, HPAGE_SIZE)) - start; + max(nd_pfn->align, PMD_SIZE)) - start; } else if (nd_pfn->mode == PFN_MODE_RAM) offset = ALIGN(start + SZ_8K + dax_label_reserve, nd_pfn->align) - start; -- 2.9.4 _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
