On Wed, Mar 6, 2019 at 4:35 PM Aneesh Kumar K.V
<[email protected]> wrote:
>
> Even if the kernel is built with THP or HUGEPAGE_PUD, the platform can decide
> not to allow huge pages based on different parameters. The huge page support
> checks are mostly arch specific and this patch provides arch specific
> callbacks/abstraction for finding alignment values we should use when
> configuring
> pfn device.
>
> Cc: Oliver O'Halloran <[email protected]>
> Signed-off-by: Aneesh Kumar K.V <[email protected]>
> ---
> arch/powerpc/include/asm/libnvdimm.h | 10 ++++++
> arch/powerpc/mm/Makefile | 1 +
> arch/powerpc/mm/nvdimm.c | 48 ++++++++++++++++++++++++++++
> arch/x86/include/asm/libnvdimm.h | 19 +++++++++++
> drivers/nvdimm/nd.h | 6 ----
> drivers/nvdimm/pfn_devs.c | 31 ++++++++++++++++--
> 6 files changed, 107 insertions(+), 8 deletions(-)
> create mode 100644 arch/powerpc/include/asm/libnvdimm.h
> create mode 100644 arch/powerpc/mm/nvdimm.c
> create mode 100644 arch/x86/include/asm/libnvdimm.h
>
> diff --git a/arch/powerpc/include/asm/libnvdimm.h
> b/arch/powerpc/include/asm/libnvdimm.h
> new file mode 100644
> index 000000000000..0928096eca90
> --- /dev/null
> +++ b/arch/powerpc/include/asm/libnvdimm.h
> @@ -0,0 +1,10 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_POWERPC_LIBNVDIMM_H
> +#define _ASM_POWERPC_LIBNVDIMM_H
> +
> +#define nd_pfn_supported_alignment nd_pfn_supported_alignment
> +extern unsigned long *nd_pfn_supported_alignments(void);
> +extern unsigned long nd_pfn_default_alignment(void);
> +extern unsigned long nd_altmap_align_size(unsigned long nd_align);
> +
> +#endif
> diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
> index f965fc33a8b7..fed0d4b3b4bc 100644
> --- a/arch/powerpc/mm/Makefile
> +++ b/arch/powerpc/mm/Makefile
> @@ -55,3 +55,4 @@ obj-$(CONFIG_PPC_BOOK3S_64) +=
> dump_linuxpagetables-book3s64.o
> endif
> obj-$(CONFIG_PPC_HTDUMP) += dump_hashpagetable.o
> obj-$(CONFIG_PPC_MEM_KEYS) += pkeys.o
> +obj-$(CONFIG_NVDIMM_PFN) += nvdimm.o
> diff --git a/arch/powerpc/mm/nvdimm.c b/arch/powerpc/mm/nvdimm.c
> new file mode 100644
> index 000000000000..ae47a65362a1
> --- /dev/null
> +++ b/arch/powerpc/mm/nvdimm.c
> @@ -0,0 +1,48 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/mm.h>
> +
> +/*
> + * We support only pte and pmd mappings for now.
> + */
> +const unsigned long *nd_pfn_supported_alignments(void)
> +{
> + static unsigned long supported_alignments[3];
> +
> +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
> +#error "Update page size"
> +#endif
> + supported_alignments[0] = PAGE_SIZE;
> +
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> + if (mmu_psize_defs[MMU_PAGE_16M].shift ||
> + mmu_psize_defs[MMU_PAGE_2M].shift)
> + supported_alignments[1] = HPAGE_PMD_SIZE;
> +#else
> + supported_alignments[1] = 0;
> +#endif
> +
> + supported_alignments[2] = 0;
> + return supported_alignments;
> +}
> +
> +/*
> + * Use pmd mapping if supported as default alignment
> + */
> +unsigned long nd_pfn_default_alignment(void)
> +{
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> + if (mmu_psize_defs[MMU_PAGE_16M].shift ||
> + mmu_psize_defs[MMU_PAGE_2M].shift)
> + return HPAGE_PMD_SIZE;
> +#endif
> + return PAGE_SIZE;
> +}
> +
> +unsigned long nd_altmap_align_size(unsigned long nd_align)
> +{
> + unsigned long vmemmap_psize;
> +
> + vmemmap_psize = 1UL << mmu_psize_defs[mmu_vmemmap_psize].shift;
> + return max(nd_align, vmemmap_psize);
> +}
It seems a bit heavyweight to have every arch define these functions
when we'll be the only ones doing anything interesting with them. I
think we'd be better off using the same method we use for PAGE_SIZE
where the arch #defines them to a variable that we fill out at
runtime. That way libnvdimm can keep using PFN_DEFAULT_ALIGNMENT or
whatever and the rest of the world doesn't need to care about the
weird stuff our firmware is doing today.
> diff --git a/arch/x86/include/asm/libnvdimm.h
> b/arch/x86/include/asm/libnvdimm.h
> new file mode 100644
> index 000000000000..3d5361db9164
> --- /dev/null
> +++ b/arch/x86/include/asm/libnvdimm.h
> @@ -0,0 +1,19 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_X86_LIBNVDIMM_H
> +#define _ASM_X86_LIBNVDIMM_H
> +
> +static inline unsigned long nd_pfn_default_alignment(void)
> +{
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> + return HPAGE_PMD_SIZE;
> +#else
> + return PAGE_SIZE;
> +#endif
> +}
> +
> +static inline unsigned long nd_altmap_align_size(unsigned long nd_align)
> +{
> + return PMD_SIZE;
> +}
> +
> +#endif
> diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
> index 379bf4305e61..e5a65868476f 100644
> --- a/drivers/nvdimm/nd.h
> +++ b/drivers/nvdimm/nd.h
> @@ -292,12 +292,6 @@ 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 6f22272e8d80..331e53bcb65e 100644
> --- a/drivers/nvdimm/pfn_devs.c
> +++ b/drivers/nvdimm/pfn_devs.c
> @@ -18,6 +18,7 @@
> #include <linux/slab.h>
> #include <linux/fs.h>
> #include <linux/mm.h>
> +#include <asm/libnvdimm.h>
> #include "nd-core.h"
> #include "pfn.h"
> #include "nd.h"
> @@ -111,6 +112,8 @@ static ssize_t align_show(struct device *dev,
> return sprintf(buf, "%ld\n", nd_pfn->align);
> }
>
> +#ifndef nd_pfn_supported_alignment
> +#define nd_pfn_supported_alignment nd_pfn_supported_alignment
> static const unsigned long *nd_pfn_supported_alignments(void)
> {
> /*
> @@ -133,6 +136,7 @@ static const unsigned long
> *nd_pfn_supported_alignments(void)
>
> return data;
> }
> +#endif
>
> static ssize_t align_store(struct device *dev,
> struct device_attribute *attr, const char *buf, size_t len)
> @@ -310,7 +314,7 @@ struct device *nd_pfn_devinit(struct nd_pfn *nd_pfn,
> return NULL;
>
> nd_pfn->mode = PFN_MODE_NONE;
> - nd_pfn->align = PFN_DEFAULT_ALIGNMENT;
> + nd_pfn->align = nd_pfn_default_alignment();
> dev = &nd_pfn->dev;
> device_initialize(&nd_pfn->dev);
> if (ndns && !__nd_attach_ndns(&nd_pfn->dev, ndns, &nd_pfn->ndns)) {
> @@ -420,6 +424,20 @@ static int nd_pfn_clear_memmap_errors(struct nd_pfn
> *nd_pfn)
> return 0;
> }
>
> +static bool nd_supported_alignment(unsigned long align)
> +{
> + int i;
> + const unsigned long *supported = nd_pfn_supported_alignments();
> +
> + if (align == 0)
> + return false;
> +
> + for (i = 0; supported[i]; i++)
> + if (align == supported[i])
> + return true;
> + return false;
> +}
> +
> int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
> {
> u64 checksum, offset;
> @@ -474,6 +492,15 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char
> *sig)
> align = 1UL << ilog2(offset);
> mode = le32_to_cpu(pfn_sb->mode);
>
> + /*
> + * Check whether the we support the alignment
> + */
> + if (!nd_supported_alignment(align)) {
> + dev_err(&nd_pfn->dev, "init failed, settings mismatch\n");
> + dev_dbg(&nd_pfn->dev, "align: %lx:%lx\n", nd_pfn->align,
> align);
print both at pr_err(), context-less errors are mostly just annoying.
> + return -EINVAL;
> + }
> +
> if (!nd_pfn->uuid) {
> /*
> * When probing a namepace via nd_pfn_probe() the uuid
> @@ -743,7 +770,7 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
> * PMD_SIZE for most architectures.
> */
> offset = ALIGN(start + SZ_8K + 64 * npfns + dax_label_reserve,
> - max(nd_pfn->align, PMD_SIZE)) - start;
> + nd_altmap_align_size(nd_pfn->align)) - start;
> } else if (nd_pfn->mode == PFN_MODE_RAM)
> offset = ALIGN(start + SZ_8K + dax_label_reserve,
> nd_pfn->align) - start;
> --
> 2.20.1
>
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