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01 Aug 2023 22:55:45 -0700 From: Vishal Verma Date: Tue, 01 Aug 2023 23:55:37 -0600 Subject: [PATCH v3 1/2] mm/memory_hotplug: split memmap_on_memory requests across memblocks MIME-Version: 1.0 Message-Id: <20230801-vv-kmem_memmap-v3-1-406e9aaf5689@intel.com> References: <20230801-vv-kmem_memmap-v3-0-406e9aaf5689@intel.com> In-Reply-To: <20230801-vv-kmem_memmap-v3-0-406e9aaf5689@intel.com> To: Andrew Morton , David Hildenbrand , Oscar Salvador , Dan Williams , Dave Jiang Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, Huang Ying , Dave Hansen , "Aneesh Kumar K.V" , Michal Hocko , Jonathan Cameron , Jeff Moyer , Vishal Verma X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=7959; i=vishal.l.verma@intel.com; h=from:subject:message-id; bh=E5mEEIt6gjKxiTw4Ms0ez32FP/kFUb2pffv4TH9UhUo=; b=owGbwMvMwCXGf25diOft7jLG02pJDCkn3z/QY5R+6++V517+ueOljdOXma7Rh56v7l68/K/yv /WHP6xp6yhlYRDjYpAVU2T5u+cj4zG57fk8gQmOMHNYmUCGMHBxCsBE+LgYGS7V9LMo1x2d++mW 1OIvpYrh50pEghW2iNr1GqjfnFj/N52RYbJA1K7qfWnMCUf0l/5+NHvppBCuO1Gmn3VZj95TvlC 5hxMA X-Developer-Key: i=vishal.l.verma@intel.com; 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Adding a larger span of memory precludes memmap_on_memory semantics. For users of hotplug such as kmem, large amounts of memory might get added from the CXL subsystem. In some cases, this amount may exceed the available 'main memory' to store the memmap for the memory being added. In this case, it is useful to have a way to place the memmap on the memory being added, even if it means splitting the addition into memblock-sized chunks. Change add_memory_resource() to loop over memblock-sized chunks of memory if caller requested memmap_on_memory, and if other conditions for it are met. Teach try_remove_memory() to also expect that a memory range being removed might have been split up into memblock sized chunks, and to loop through those as needed. Cc: Andrew Morton Cc: David Hildenbrand Cc: Michal Hocko Cc: Oscar Salvador Cc: Dan Williams Cc: Dave Jiang Cc: Dave Hansen Cc: Huang Ying Suggested-by: David Hildenbrand Signed-off-by: Vishal Verma --- mm/memory_hotplug.c | 150 ++++++++++++++++++++++++++++++++-------------------- 1 file changed, 93 insertions(+), 57 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index d282664f558e..cae03c8d4bbf 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1383,6 +1383,44 @@ static bool mhp_supports_memmap_on_memory(unsigned long size) return arch_supports_memmap_on_memory(vmemmap_size); } +static int add_memory_create_devices(int nid, struct memory_group *group, + u64 start, u64 size, mhp_t mhp_flags) +{ + struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) }; + struct vmem_altmap mhp_altmap = { + .base_pfn = PHYS_PFN(start), + .end_pfn = PHYS_PFN(start + size - 1), + }; + int ret; + + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY)) { + mhp_altmap.free = memory_block_memmap_on_memory_pages(); + params.altmap = kmalloc(sizeof(struct vmem_altmap), GFP_KERNEL); + if (!params.altmap) + return -ENOMEM; + + memcpy(params.altmap, &mhp_altmap, sizeof(mhp_altmap)); + } + + /* call arch's memory hotadd */ + ret = arch_add_memory(nid, start, size, ¶ms); + if (ret < 0) + goto error; + + /* create memory block devices after memory was added */ + ret = create_memory_block_devices(start, size, params.altmap, group); + if (ret) { + arch_remove_memory(start, size, NULL); + goto error; + } + + return 0; + +error: + kfree(params.altmap); + return ret; +} + /* * NOTE: The caller must call lock_device_hotplug() to serialize hotplug * and online/offline operations (triggered e.g. by sysfs). @@ -1391,14 +1429,10 @@ static bool mhp_supports_memmap_on_memory(unsigned long size) */ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) { - struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) }; + unsigned long memblock_size = memory_block_size_bytes(); enum memblock_flags memblock_flags = MEMBLOCK_NONE; - struct vmem_altmap mhp_altmap = { - .base_pfn = PHYS_PFN(res->start), - .end_pfn = PHYS_PFN(res->end), - }; struct memory_group *group = NULL; - u64 start, size; + u64 start, size, cur_start; bool new_node = false; int ret; @@ -1439,28 +1473,21 @@ 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)) { - mhp_altmap.free = memory_block_memmap_on_memory_pages(); - params.altmap = kmalloc(sizeof(struct vmem_altmap), GFP_KERNEL); - if (!params.altmap) + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) && + mhp_supports_memmap_on_memory(memblock_size)) { + for (cur_start = start; cur_start < start + size; + cur_start += memblock_size) { + ret = add_memory_create_devices(nid, group, cur_start, + memblock_size, + mhp_flags); + if (ret) goto error; - - memcpy(params.altmap, &mhp_altmap, sizeof(mhp_altmap)); } - /* fallback to not using altmap */ - } - - /* call arch's memory hotadd */ - ret = arch_add_memory(nid, start, size, ¶ms); - if (ret < 0) - goto error_free; - - /* create memory block devices after memory was added */ - ret = create_memory_block_devices(start, size, params.altmap, group); - if (ret) { - arch_remove_memory(start, size, NULL); - goto error_free; + } else { + ret = add_memory_create_devices(nid, group, start, size, + mhp_flags); + if (ret) + goto error; } if (new_node) { @@ -1497,8 +1524,6 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) walk_memory_blocks(start, size, NULL, online_memory_block); return ret; -error_free: - kfree(params.altmap); error: if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) memblock_remove(start, size); @@ -2149,40 +2174,14 @@ void try_offline_node(int nid) } EXPORT_SYMBOL(try_offline_node); -static int __ref try_remove_memory(u64 start, u64 size) +static void __ref __try_remove_memory(int nid, u64 start, u64 size) { - int ret; - struct memory_block *mem; - int rc = 0, nid = NUMA_NO_NODE; struct vmem_altmap *altmap = NULL; + struct memory_block *mem; + int ret; - BUG_ON(check_hotplug_memory_range(start, size)); - - /* - * All memory blocks must be offlined before removing memory. Check - * whether all memory blocks in question are offline and return error - * if this is not the case. - * - * While at it, determine the nid. Note that if we'd have mixed nodes, - * we'd only try to offline the last determined one -- which is good - * enough for the cases we care about. - */ - rc = walk_memory_blocks(start, size, &nid, check_memblock_offlined_cb); - if (rc) - return rc; - - /* - * We only support removing memory added with MHP_MEMMAP_ON_MEMORY in - * the same granularity it was added - a single memory block. - */ ret = walk_memory_blocks(start, size, &mem, test_has_altmap_cb); if (ret) { - if (size != memory_block_size_bytes()) { - pr_warn("Refuse to remove %#llx - %#llx," - "wrong granularity\n", - start, start + size); - return -EINVAL; - } altmap = mem->altmap; /* * Mark altmap NULL so that we can add a debug @@ -2221,6 +2220,43 @@ static int __ref try_remove_memory(u64 start, u64 size) try_offline_node(nid); mem_hotplug_done(); +} + +static int __ref try_remove_memory(u64 start, u64 size) +{ + int ret, nid = NUMA_NO_NODE; + + BUG_ON(check_hotplug_memory_range(start, size)); + + /* + * All memory blocks must be offlined before removing memory. Check + * whether all memory blocks in question are offline and return error + * if this is not the case. + * + * While at it, determine the nid. Note that if we'd have mixed nodes, + * we'd only try to offline the last determined one -- which is good + * enough for the cases we care about. + */ + ret = walk_memory_blocks(start, size, &nid, check_memblock_offlined_cb); + if (ret) + return ret; + + /* + * For memmap_on_memory, the altmaps could have been added on + * a per-memblock basis. Loop through the entire range if so, + * and remove each memblock and its altmap. + */ + if (mhp_memmap_on_memory()) { + unsigned long memblock_size = memory_block_size_bytes(); + u64 cur_start; + + for (cur_start = start; cur_start < start + size; + cur_start += memblock_size) + __try_remove_memory(nid, cur_start, memblock_size); + } else { + __try_remove_memory(nid, start, size); + } + return 0; } From patchwork Wed Aug 2 05:55:38 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Verma, Vishal L" X-Patchwork-Id: 13337664 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 759FBC04A94 for ; Wed, 2 Aug 2023 05:56:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3AEB428012A; Wed, 2 Aug 2023 01:56:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2E65B280112; 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d="scan'208";a="852746663" Received: from hongrudi-mobl.amr.corp.intel.com (HELO [192.168.1.200]) ([10.209.173.200]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Aug 2023 22:55:46 -0700 From: Vishal Verma Date: Tue, 01 Aug 2023 23:55:38 -0600 Subject: [PATCH v3 2/2] dax/kmem: allow kmem to add memory with memmap_on_memory MIME-Version: 1.0 Message-Id: <20230801-vv-kmem_memmap-v3-2-406e9aaf5689@intel.com> References: <20230801-vv-kmem_memmap-v3-0-406e9aaf5689@intel.com> In-Reply-To: <20230801-vv-kmem_memmap-v3-0-406e9aaf5689@intel.com> To: Andrew Morton , David Hildenbrand , Oscar Salvador , Dan Williams , Dave Jiang Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, Huang Ying , Dave Hansen , "Aneesh Kumar K.V" , Michal Hocko , Jonathan Cameron , Jeff Moyer , Vishal Verma X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=4390; i=vishal.l.verma@intel.com; h=from:subject:message-id; bh=PQ203zHCVt3CEYS9d0oE1EzhXByb08+AR/dYJJo5JtE=; 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Enroll kmem-managed memory for memmap_on_memory semantics as a default. Add a sysfs override under the dax device to opt out of this behavior. Cc: Andrew Morton Cc: David Hildenbrand Cc: Michal Hocko Cc: Oscar Salvador Cc: Dan Williams Cc: Dave Jiang Cc: Dave Hansen Cc: Huang Ying Signed-off-by: Vishal Verma Reviewed-by: Jonathan Cameron --- drivers/dax/dax-private.h | 1 + drivers/dax/bus.c | 42 ++++++++++++++++++++++++++++++++++++++++++ drivers/dax/kmem.c | 8 +++++++- 3 files changed, 50 insertions(+), 1 deletion(-) diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h index 27cf2daaaa79..446617b73aea 100644 --- a/drivers/dax/dax-private.h +++ b/drivers/dax/dax-private.h @@ -70,6 +70,7 @@ struct dev_dax { struct ida ida; struct device dev; struct dev_pagemap *pgmap; + bool memmap_on_memory; int nr_range; struct dev_dax_range { unsigned long pgoff; diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index 0ee96e6fc426..e9c0349b6244 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -1269,6 +1269,40 @@ static ssize_t numa_node_show(struct device *dev, } static DEVICE_ATTR_RO(numa_node); +static ssize_t memmap_on_memory_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + + return sprintf(buf, "%d\n", dev_dax->memmap_on_memory); +} + +static ssize_t memmap_on_memory_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + struct dax_region *dax_region = dev_dax->region; + ssize_t rc; + bool val; + + rc = kstrtobool(buf, &val); + if (rc) + return rc; + + device_lock(dax_region->dev); + if (!dax_region->dev->driver) { + device_unlock(dax_region->dev); + return -ENXIO; + } + + dev_dax->memmap_on_memory = val; + + device_unlock(dax_region->dev); + return rc == 0 ? len : rc; +} +static DEVICE_ATTR_RW(memmap_on_memory); + static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n) { struct device *dev = container_of(kobj, struct device, kobj); @@ -1295,6 +1329,7 @@ static struct attribute *dev_dax_attributes[] = { &dev_attr_align.attr, &dev_attr_resource.attr, &dev_attr_numa_node.attr, + &dev_attr_memmap_on_memory.attr, NULL, }; @@ -1400,6 +1435,13 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data) dev_dax->align = dax_region->align; ida_init(&dev_dax->ida); + /* + * If supported by memory_hotplug, allow memmap_on_memory behavior by + * default. This can be overridden via sysfs before handing the memory + * over to kmem if desired. + */ + dev_dax->memmap_on_memory = true; + inode = dax_inode(dax_dev); dev->devt = inode->i_rdev; dev->bus = &dax_bus_type; diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c index c57acb73e3db..0aa6c45a4e5a 100644 --- a/drivers/dax/kmem.c +++ b/drivers/dax/kmem.c @@ -12,6 +12,7 @@ #include #include #include +#include #include "dax-private.h" #include "bus.h" @@ -56,6 +57,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) unsigned long total_len = 0; struct dax_kmem_data *data; int i, rc, mapped = 0; + mhp_t mhp_flags; int numa_node; /* @@ -136,12 +138,16 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) */ res->flags = IORESOURCE_SYSTEM_RAM; + mhp_flags = MHP_NID_IS_MGID; + if (dev_dax->memmap_on_memory) + mhp_flags |= MHP_MEMMAP_ON_MEMORY; + /* * Ensure that future kexec'd kernels will not treat * this as RAM automatically. */ rc = add_memory_driver_managed(data->mgid, range.start, - range_len(&range), kmem_name, MHP_NID_IS_MGID); + range_len(&range), kmem_name, mhp_flags); if (rc) { dev_warn(dev, "mapping%d: %#llx-%#llx memory add failed\n",