Re: [PATCH 14/25] memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag

Ira Weiny
2019-06-26T21:13:02Z

On Wed, Jun 26, 2019 at 02:27:13PM +0200, Christoph Hellwig wrote:
> Add a flags field to struct dev_pagemap to replace the altmap_valid
> boolean to be a little more extensible. Also add a pgmap_altmap() helper
> to find the optional altmap and clean up the code using the altmap using
> it.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Ira Weiny <ira.weiny@intel.com>

> ---
> arch/powerpc/mm/mem.c | 10 +---------
> arch/x86/mm/init_64.c | 8 ++------
> drivers/nvdimm/pfn_devs.c | 3 +--
> drivers/nvdimm/pmem.c | 1 -
> include/linux/memremap.h | 12 +++++++++++-
> kernel/memremap.c | 26 ++++++++++----------------
> mm/hmm.c | 1 -
> mm/memory_hotplug.c | 6 ++----
> mm/page_alloc.c | 5 ++---
> 9 files changed, 29 insertions(+), 43 deletions(-)
>
> diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
> index cba29131bccc..f774d80df025 100644
> --- a/arch/powerpc/mm/mem.c
> +++ b/arch/powerpc/mm/mem.c
> @@ -131,17 +131,9 @@ void __ref arch_remove_memory(int nid, u64 start, u64 size,
> {
> unsigned long start_pfn = start >> PAGE_SHIFT;
> unsigned long nr_pages = size >> PAGE_SHIFT;
> - struct page *page;
> + struct page *page = pfn_to_page(start_pfn) + vmem_altmap_offset(altmap);
> int ret;
>
> - /*
> - * If we have an altmap then we need to skip over any reserved PFNs
> - * when querying the zone.
> - */
> - page = pfn_to_page(start_pfn);
> - if (altmap)
> - page += vmem_altmap_offset(altmap);
> -
> __remove_pages(page_zone(page), start_pfn, nr_pages, altmap);
>
> /* Remove htab bolted mappings for this section of memory */
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 693aaf28d5fe..3139e992ef9d 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -1211,13 +1211,9 @@ void __ref arch_remove_memory(int nid, u64 start, u64 size,
> {
> unsigned long start_pfn = start >> PAGE_SHIFT;
> unsigned long nr_pages = size >> PAGE_SHIFT;
> - struct page *page = pfn_to_page(start_pfn);
> - struct zone *zone;
> + struct page *page = pfn_to_page(start_pfn) + vmem_altmap_offset(altmap);
> + struct zone *zone = page_zone(page);
>
> - /* With altmap the first mapped page is offset from @start */
> - if (altmap)
> - page += vmem_altmap_offset(altmap);
> - zone = page_zone(page);
> __remove_pages(zone, start_pfn, nr_pages, altmap);
> kernel_physical_mapping_remove(start, start + size);
> }
> diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
> index 0f81fc56bbfd..55fb6b7433ed 100644
> --- a/drivers/nvdimm/pfn_devs.c
> +++ b/drivers/nvdimm/pfn_devs.c
> @@ -622,7 +622,6 @@ static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
> if (offset < reserve)
> return -EINVAL;
> nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
> - pgmap->altmap_valid = false;
> } else if (nd_pfn->mode == PFN_MODE_PMEM) {
> nd_pfn->npfns = PFN_SECTION_ALIGN_UP((resource_size(res)
> - offset) / PAGE_SIZE);
> @@ -634,7 +633,7 @@ static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
> memcpy(altmap, &__altmap, sizeof(*altmap));
> altmap->free = PHYS_PFN(offset - reserve);
> altmap->alloc = 0;
> - pgmap->altmap_valid = true;
> + pgmap->flags |= PGMAP_ALTMAP_VALID;
> } else
> return -ENXIO;
>
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 093408ce40ad..e7d8cc9f41e8 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -412,7 +412,6 @@ static int pmem_attach_disk(struct device *dev,
> bb_res.start += pmem->data_offset;
> } else if (pmem_should_map_pages(dev)) {
> memcpy(&pmem->pgmap.res, &nsio->res, sizeof(pmem->pgmap.res));
> - pmem->pgmap.altmap_valid = false;
> pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
> pmem->pgmap.ops = &fsdax_pagemap_ops;
> addr = devm_memremap_pages(dev, &pmem->pgmap);
> diff --git a/include/linux/memremap.h b/include/linux/memremap.h
> index 336eca601dad..e25685b878e9 100644
> --- a/include/linux/memremap.h
> +++ b/include/linux/memremap.h
> @@ -88,6 +88,8 @@ struct dev_pagemap_ops {
> vm_fault_t (*migrate_to_ram)(struct vm_fault *vmf);
> };
>
> +#define PGMAP_ALTMAP_VALID (1 << 0)
> +
> /**
> * struct dev_pagemap - metadata for ZONE_DEVICE mappings
> * @altmap: pre-allocated/reserved memory for vmemmap allocations
> @@ -96,19 +98,27 @@ struct dev_pagemap_ops {
> * @dev: host device of the mapping for debug
> * @data: private data pointer for page_free()
> * @type: memory type: see MEMORY_* in memory_hotplug.h
> + * @flags: PGMAP_* flags to specify defailed behavior
> * @ops: method table
> */
> struct dev_pagemap {
> struct vmem_altmap altmap;
> - bool altmap_valid;
> struct resource res;
> struct percpu_ref *ref;
> struct device *dev;
> enum memory_type type;
> + unsigned int flags;
> u64 pci_p2pdma_bus_offset;
> const struct dev_pagemap_ops *ops;
> };
>
> +static inline struct vmem_altmap *pgmap_altmap(struct dev_pagemap *pgmap)
> +{
> + if (pgmap->flags & PGMAP_ALTMAP_VALID)
> + return &pgmap->altmap;
> + return NULL;
> +}
> +
> #ifdef CONFIG_ZONE_DEVICE
> void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap);
> void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap);
> diff --git a/kernel/memremap.c b/kernel/memremap.c
> index 6c3dbb692037..eee490e7d7e1 100644
> --- a/kernel/memremap.c
> +++ b/kernel/memremap.c
> @@ -54,14 +54,8 @@ static void pgmap_array_delete(struct resource *res)
>
> static unsigned long pfn_first(struct dev_pagemap *pgmap)
> {
> - const struct resource *res = &pgmap->res;
> - struct vmem_altmap *altmap = &pgmap->altmap;
> - unsigned long pfn;
> -
> - pfn = res->start >> PAGE_SHIFT;
> - if (pgmap->altmap_valid)
> - pfn += vmem_altmap_offset(altmap);
> - return pfn;
> + return (pgmap->res.start >> PAGE_SHIFT) +
> + vmem_altmap_offset(pgmap_altmap(pgmap));
> }
>
> static unsigned long pfn_end(struct dev_pagemap *pgmap)
> @@ -109,7 +103,7 @@ static void devm_memremap_pages_release(void *data)
> align_size >> PAGE_SHIFT, NULL);
> } else {
> arch_remove_memory(nid, align_start, align_size,
> - pgmap->altmap_valid ? &pgmap->altmap : NULL);
> + pgmap_altmap(pgmap));
> kasan_remove_zero_shadow(__va(align_start), align_size);
> }
> mem_hotplug_done();
> @@ -129,8 +123,8 @@ static void devm_memremap_pages_release(void *data)
> * 1/ At a minimum the res, ref and type and ops members of @pgmap must be
> * initialized by the caller before passing it to this function
> *
> - * 2/ The altmap field may optionally be initialized, in which case altmap_valid
> - * must be set to true
> + * 2/ The altmap field may optionally be initialized, in which case
> + * PGMAP_ALTMAP_VALID must be set in pgmap->flags.
> *
> * 3/ pgmap->ref must be 'live' on entry and will be killed and reaped
> * at devm_memremap_pages_release() time, or if this routine fails.
> @@ -142,15 +136,13 @@ static void devm_memremap_pages_release(void *data)
> void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
> {
> resource_size_t align_start, align_size, align_end;
> - struct vmem_altmap *altmap = pgmap->altmap_valid ?
> - &pgmap->altmap : NULL;
> struct resource *res = &pgmap->res;
> struct dev_pagemap *conflict_pgmap;
> struct mhp_restrictions restrictions = {
> /*
> * We do not want any optional features only our own memmap
> */
> - .altmap = altmap,
> + .altmap = pgmap_altmap(pgmap),
> };
> pgprot_t pgprot = PAGE_KERNEL;
> int error, nid, is_ram;
> @@ -274,7 +266,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
>
> zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
> move_pfn_range_to_zone(zone, align_start >> PAGE_SHIFT,
> - align_size >> PAGE_SHIFT, altmap);
> + align_size >> PAGE_SHIFT, pgmap_altmap(pgmap));
> }
>
> mem_hotplug_done();
> @@ -319,7 +311,9 @@ EXPORT_SYMBOL_GPL(devm_memunmap_pages);
> unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
> {
> /* number of pfns from base where pfn_to_page() is valid */
> - return altmap->reserve + altmap->free;
> + if (altmap)
> + return altmap->reserve + altmap->free;
> + return 0;
> }
>
> void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
> diff --git a/mm/hmm.c b/mm/hmm.c
> index 36e25cdbdac1..e4470462298f 100644
> --- a/mm/hmm.c
> +++ b/mm/hmm.c
> @@ -1442,7 +1442,6 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
> devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
> devmem->pagemap.res = *devmem->resource;
> devmem->pagemap.ops = &hmm_pagemap_ops;
> - devmem->pagemap.altmap_valid = false;
> devmem->pagemap.ref = &devmem->ref;
>
> result = devm_memremap_pages(devmem->device, &devmem->pagemap);
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index e096c987d261..6166ba5a15f3 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -557,10 +557,8 @@ void __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
> int sections_to_remove;
>
> /* In the ZONE_DEVICE case device driver owns the memory region */
> - if (is_dev_zone(zone)) {
> - if (altmap)
> - map_offset = vmem_altmap_offset(altmap);
> - }
> + if (is_dev_zone(zone))
> + map_offset = vmem_altmap_offset(altmap);
>
> clear_zone_contiguous(zone);
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index d66bc8abe0af..17a39d40a556 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5853,6 +5853,7 @@ void __ref memmap_init_zone_device(struct zone *zone,
> {
> unsigned long pfn, end_pfn = start_pfn + size;
> struct pglist_data *pgdat = zone->zone_pgdat;
> + struct vmem_altmap *altmap = pgmap_altmap(pgmap);
> unsigned long zone_idx = zone_idx(zone);
> unsigned long start = jiffies;
> int nid = pgdat->node_id;
> @@ -5865,9 +5866,7 @@ void __ref memmap_init_zone_device(struct zone *zone,
> * of the pages reserved for the memmap, so we can just jump to
> * the end of that region and start processing the device pages.
> */
> - if (pgmap->altmap_valid) {
> - struct vmem_altmap *altmap = &pgmap->altmap;
> -
> + if (altmap) {
> start_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
> size = end_pfn - start_pfn;
> }
> --
> 2.20.1
>
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