From: Jérôme Glisse <jglisse@xxxxxxxxxx> Subject: mm/hmm: add new helper to hotplug CDM memory region Unlike unaddressable memory, coherent device memory has a real resource associated with it on the system (as CPU can address it). Add a new helper to hotplug such memory within the HMM framework. Link: http://lkml.kernel.org/r/20170817000548.32038-20-jglisse@xxxxxxxxxx Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx> Reviewed-by: Balbir Singh <bsingharora@xxxxxxxxx> Cc: Aneesh Kumar <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: David Nellans <dnellans@xxxxxxxxxx> Cc: Evgeny Baskakov <ebaskakov@xxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: John Hubbard <jhubbard@xxxxxxxxxx> Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Mark Hairgrove <mhairgrove@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> Cc: Sherry Cheung <SCheung@xxxxxxxxxx> Cc: Subhash Gutti <sgutti@xxxxxxxxxx> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> Cc: Bob Liu <liubo95@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/hmm.h | 3 + mm/hmm.c | 88 +++++++++++++++++++++++++++++++++++++++--- 2 files changed, 86 insertions(+), 5 deletions(-) diff -puN include/linux/hmm.h~mm-hmm-add-new-helper-to-hotplug-cdm-memory-region-v3 include/linux/hmm.h --- a/include/linux/hmm.h~mm-hmm-add-new-helper-to-hotplug-cdm-memory-region-v3 +++ a/include/linux/hmm.h @@ -443,6 +443,9 @@ struct hmm_devmem { struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops, struct device *device, unsigned long size); +struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops, + struct device *device, + struct resource *res); void hmm_devmem_remove(struct hmm_devmem *devmem); /* diff -puN mm/hmm.c~mm-hmm-add-new-helper-to-hotplug-cdm-memory-region-v3 mm/hmm.c --- a/mm/hmm.c~mm-hmm-add-new-helper-to-hotplug-cdm-memory-region-v3 +++ a/mm/hmm.c @@ -839,7 +839,11 @@ static void hmm_devmem_release(struct de zone = page_zone(page); mem_hotplug_begin(); - __remove_pages(zone, start_pfn, npages); + if (resource->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) + __remove_pages(zone, start_pfn, npages); + else + arch_remove_memory(start_pfn << PAGE_SHIFT, + npages << PAGE_SHIFT); mem_hotplug_done(); hmm_devmem_radix_release(resource); @@ -875,7 +879,11 @@ static int hmm_devmem_pages_create(struc if (is_ram == REGION_INTERSECTS) return -ENXIO; - devmem->pagemap.type = MEMORY_DEVICE_PRIVATE; + if (devmem->resource->desc == IORES_DESC_DEVICE_PUBLIC_MEMORY) + devmem->pagemap.type = MEMORY_DEVICE_PUBLIC; + else + devmem->pagemap.type = MEMORY_DEVICE_PRIVATE; + devmem->pagemap.res = devmem->resource; devmem->pagemap.page_fault = hmm_devmem_fault; devmem->pagemap.page_free = hmm_devmem_free; @@ -920,9 +928,15 @@ static int hmm_devmem_pages_create(struc * over the device memory is un-accessible thus we do not want to * create a linear mapping for the memory like arch_add_memory() * would do. + * + * For device public memory, which is accesible by the CPU, we do + * want the linear mapping and thus use arch_add_memory(). */ - ret = add_pages(nid, align_start >> PAGE_SHIFT, - align_size >> PAGE_SHIFT, false); + if (devmem->pagemap.type == MEMORY_DEVICE_PUBLIC) + ret = arch_add_memory(nid, align_start, align_size, false); + else + ret = add_pages(nid, align_start >> PAGE_SHIFT, + align_size >> PAGE_SHIFT, false); if (ret) { mem_hotplug_done(); goto error_add_memory; @@ -1069,6 +1083,67 @@ error_percpu_ref: } EXPORT_SYMBOL(hmm_devmem_add); +struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops, + struct device *device, + struct resource *res) +{ + struct hmm_devmem *devmem; + int ret; + + if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY) + return ERR_PTR(-EINVAL); + + static_branch_enable(&device_private_key); + + devmem = devres_alloc_node(&hmm_devmem_release, sizeof(*devmem), + GFP_KERNEL, dev_to_node(device)); + if (!devmem) + return ERR_PTR(-ENOMEM); + + init_completion(&devmem->completion); + devmem->pfn_first = -1UL; + devmem->pfn_last = -1UL; + devmem->resource = res; + devmem->device = device; + devmem->ops = ops; + + ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release, + 0, GFP_KERNEL); + if (ret) + goto error_percpu_ref; + + ret = devm_add_action(device, hmm_devmem_ref_exit, &devmem->ref); + if (ret) + goto error_devm_add_action; + + + devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; + devmem->pfn_last = devmem->pfn_first + + (resource_size(devmem->resource) >> PAGE_SHIFT); + + ret = hmm_devmem_pages_create(devmem); + if (ret) + goto error_devm_add_action; + + devres_add(device, devmem); + + ret = devm_add_action(device, hmm_devmem_ref_kill, &devmem->ref); + if (ret) { + hmm_devmem_remove(devmem); + return ERR_PTR(ret); + } + + return devmem; + +error_devm_add_action: + hmm_devmem_ref_kill(&devmem->ref); + hmm_devmem_ref_exit(&devmem->ref); +error_percpu_ref: + devres_free(devmem); + return ERR_PTR(ret); +} +EXPORT_SYMBOL(hmm_devmem_add_resource); + /* * hmm_devmem_remove() - remove device memory (kill and free ZONE_DEVICE) * @@ -1082,6 +1157,7 @@ void hmm_devmem_remove(struct hmm_devmem { resource_size_t start, size; struct device *device; + bool cdm = false; if (!devmem) return; @@ -1090,11 +1166,13 @@ void hmm_devmem_remove(struct hmm_devmem start = devmem->resource->start; size = resource_size(devmem->resource); + cdm = devmem->resource->desc == IORES_DESC_DEVICE_PUBLIC_MEMORY; hmm_devmem_ref_kill(&devmem->ref); hmm_devmem_ref_exit(&devmem->ref); hmm_devmem_pages_remove(devmem); - devm_release_mem_region(device, start, size); + if (!cdm) + devm_release_mem_region(device, start, size); } EXPORT_SYMBOL(hmm_devmem_remove); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
