From e3c2bfdd33a30b34674fb8839f5476ab2702c1c1 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Tue, 8 Aug 2023 14:44:57 +0530 Subject: [PATCH] mm/memory_hotplug: allow memmap on memory hotplug request to fallback If not supported, fallback to not using memap on memmory. This avoids the need for callers to do the fallback. Link: https://lkml.kernel.org/r/20230808091501.287660-3-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Acked-by: Michal Hocko Acked-by: David Hildenbrand Cc: Christophe Leroy Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Vishal Verma Signed-off-by: Andrew Morton --- drivers/acpi/acpi_memhotplug.c | 3 +-- include/linux/memory_hotplug.h | 3 ++- mm/memory_hotplug.c | 13 ++++++------- 3 files changed, 9 insertions(+), 10 deletions(-) diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c index 24f662d8bd39..d0c1a71007d0 100644 --- a/drivers/acpi/acpi_memhotplug.c +++ b/drivers/acpi/acpi_memhotplug.c @@ -211,8 +211,7 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device) if (!info->length) continue; - if (mhp_supports_memmap_on_memory(info->length)) - mhp_flags |= MHP_MEMMAP_ON_MEMORY; + mhp_flags |= MHP_MEMMAP_ON_MEMORY; result = __add_memory(mgid, info->start_addr, info->length, mhp_flags); diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 013c69753c91..7d2076583494 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -97,6 +97,8 @@ typedef int __bitwise mhp_t; * To do so, we will use the beginning of the hot-added range to build * the page tables for the memmap array that describes the entire range. * Only selected architectures support it with SPARSE_VMEMMAP. + * This is only a hint, the core kernel can decide to not do this based on + * different alignment checks. */ #define MHP_MEMMAP_ON_MEMORY ((__force mhp_t)BIT(1)) /* @@ -354,7 +356,6 @@ extern struct zone *zone_for_pfn_range(int online_type, int nid, extern int arch_create_linear_mapping(int nid, u64 start, u64 size, struct mhp_params *params); void arch_remove_linear_mapping(u64 start, u64 size); -extern bool mhp_supports_memmap_on_memory(unsigned long size); #endif /* CONFIG_MEMORY_HOTPLUG */ #endif /* __LINUX_MEMORY_HOTPLUG_H */ diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 7cfd13c91568..eca32ccd45cc 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1247,7 +1247,7 @@ static int online_memory_block(struct memory_block *mem, void *arg) return device_online(&mem->dev); } -bool mhp_supports_memmap_on_memory(unsigned long size) +static bool mhp_supports_memmap_on_memory(unsigned long size) { unsigned long nr_vmemmap_pages = size / PAGE_SIZE; unsigned long vmemmap_size = nr_vmemmap_pages * sizeof(struct page); @@ -1339,13 +1339,12 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) * Self hosted memmap array */ if (mhp_flags & MHP_MEMMAP_ON_MEMORY) { - if (!mhp_supports_memmap_on_memory(size)) { - ret = -EINVAL; - goto error; + if (mhp_supports_memmap_on_memory(size)) { + mhp_altmap.free = PHYS_PFN(size); + mhp_altmap.base_pfn = PHYS_PFN(start); + params.altmap = &mhp_altmap; } - mhp_altmap.free = PHYS_PFN(size); - mhp_altmap.base_pfn = PHYS_PFN(start); - params.altmap = &mhp_altmap; + /* fallback to not using altmap */ } /* call arch's memory hotadd */