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![Aneesh Kumar K.V](/assets/img/avatar_default.png)
By default, all nodes are assigned to the default memory tier which is the memory tier designated for nodes with DRAM Set dax kmem device node's tier to slower memory tier by assigning abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE. Low-level drivers like papr_scm or ACPI NFIT can initialize memory device type to a more accurate value based on device tree details or HMAT. If the kernel doesn't find the memory type initialized, a default slower memory type is assigned by the kmem driver. [aneesh.kumar@linux.ibm.com: assign correct memory type for multiple dax devices with the same node affinity] Link: https://lkml.kernel.org/r/20220826100224.542312-1-aneesh.kumar@linux.ibm.com Link: https://lkml.kernel.org/r/20220818131042.113280-5-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Acked-by: Wei Xu <weixugc@google.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Bharata B Rao <bharata@amd.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hesham Almatary <hesham.almatary@huawei.com> Cc: Jagdish Gediya <jvgediya.oss@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tim Chen <tim.c.chen@intel.com> Cc: Yang Shi <shy828301@gmail.com> Cc: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
284 lines
7.2 KiB
C
284 lines
7.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright(c) 2016-2019 Intel Corporation. All rights reserved. */
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#include <linux/memremap.h>
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#include <linux/pagemap.h>
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#include <linux/memory.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/pfn_t.h>
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#include <linux/slab.h>
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#include <linux/dax.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/mman.h>
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#include <linux/memory-tiers.h>
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#include "dax-private.h"
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#include "bus.h"
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/*
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* Default abstract distance assigned to the NUMA node onlined
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* by DAX/kmem if the low level platform driver didn't initialize
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* one for this NUMA node.
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*/
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#define MEMTIER_DEFAULT_DAX_ADISTANCE (MEMTIER_ADISTANCE_DRAM * 5)
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/* Memory resource name used for add_memory_driver_managed(). */
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static const char *kmem_name;
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/* Set if any memory will remain added when the driver will be unloaded. */
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static bool any_hotremove_failed;
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static int dax_kmem_range(struct dev_dax *dev_dax, int i, struct range *r)
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{
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struct dev_dax_range *dax_range = &dev_dax->ranges[i];
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struct range *range = &dax_range->range;
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/* memory-block align the hotplug range */
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r->start = ALIGN(range->start, memory_block_size_bytes());
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r->end = ALIGN_DOWN(range->end + 1, memory_block_size_bytes()) - 1;
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if (r->start >= r->end) {
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r->start = range->start;
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r->end = range->end;
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return -ENOSPC;
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}
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return 0;
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}
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struct dax_kmem_data {
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const char *res_name;
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int mgid;
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struct resource *res[];
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};
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static struct memory_dev_type *dax_slowmem_type;
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static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
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{
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struct device *dev = &dev_dax->dev;
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unsigned long total_len = 0;
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struct dax_kmem_data *data;
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int i, rc, mapped = 0;
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int numa_node;
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/*
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* Ensure good NUMA information for the persistent memory.
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* Without this check, there is a risk that slow memory
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* could be mixed in a node with faster memory, causing
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* unavoidable performance issues.
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*/
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numa_node = dev_dax->target_node;
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if (numa_node < 0) {
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dev_warn(dev, "rejecting DAX region with invalid node: %d\n",
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numa_node);
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return -EINVAL;
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}
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for (i = 0; i < dev_dax->nr_range; i++) {
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struct range range;
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rc = dax_kmem_range(dev_dax, i, &range);
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if (rc) {
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dev_info(dev, "mapping%d: %#llx-%#llx too small after alignment\n",
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i, range.start, range.end);
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continue;
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}
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total_len += range_len(&range);
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}
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if (!total_len) {
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dev_warn(dev, "rejecting DAX region without any memory after alignment\n");
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return -EINVAL;
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}
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init_node_memory_type(numa_node, dax_slowmem_type);
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rc = -ENOMEM;
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data = kzalloc(struct_size(data, res, dev_dax->nr_range), GFP_KERNEL);
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if (!data)
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goto err_dax_kmem_data;
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data->res_name = kstrdup(dev_name(dev), GFP_KERNEL);
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if (!data->res_name)
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goto err_res_name;
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rc = memory_group_register_static(numa_node, total_len);
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if (rc < 0)
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goto err_reg_mgid;
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data->mgid = rc;
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for (i = 0; i < dev_dax->nr_range; i++) {
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struct resource *res;
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struct range range;
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rc = dax_kmem_range(dev_dax, i, &range);
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if (rc)
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continue;
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/* Region is permanently reserved if hotremove fails. */
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res = request_mem_region(range.start, range_len(&range), data->res_name);
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if (!res) {
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dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve region\n",
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i, range.start, range.end);
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/*
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* Once some memory has been onlined we can't
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* assume that it can be un-onlined safely.
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*/
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if (mapped)
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continue;
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rc = -EBUSY;
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goto err_request_mem;
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}
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data->res[i] = res;
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/*
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* Set flags appropriate for System RAM. Leave ..._BUSY clear
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* so that add_memory() can add a child resource. Do not
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* inherit flags from the parent since it may set new flags
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* unknown to us that will break add_memory() below.
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*/
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res->flags = IORESOURCE_SYSTEM_RAM;
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/*
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* Ensure that future kexec'd kernels will not treat
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* this as RAM automatically.
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*/
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rc = add_memory_driver_managed(data->mgid, range.start,
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range_len(&range), kmem_name, MHP_NID_IS_MGID);
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if (rc) {
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dev_warn(dev, "mapping%d: %#llx-%#llx memory add failed\n",
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i, range.start, range.end);
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release_resource(res);
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kfree(res);
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data->res[i] = NULL;
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if (mapped)
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continue;
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goto err_request_mem;
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}
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mapped++;
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}
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dev_set_drvdata(dev, data);
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return 0;
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err_request_mem:
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memory_group_unregister(data->mgid);
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err_reg_mgid:
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kfree(data->res_name);
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err_res_name:
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kfree(data);
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err_dax_kmem_data:
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clear_node_memory_type(numa_node, dax_slowmem_type);
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return rc;
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}
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#ifdef CONFIG_MEMORY_HOTREMOVE
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static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
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{
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int i, success = 0;
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int node = dev_dax->target_node;
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struct device *dev = &dev_dax->dev;
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struct dax_kmem_data *data = dev_get_drvdata(dev);
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/*
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* We have one shot for removing memory, if some memory blocks were not
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* offline prior to calling this function remove_memory() will fail, and
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* there is no way to hotremove this memory until reboot because device
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* unbind will succeed even if we return failure.
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*/
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for (i = 0; i < dev_dax->nr_range; i++) {
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struct range range;
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int rc;
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rc = dax_kmem_range(dev_dax, i, &range);
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if (rc)
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continue;
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rc = remove_memory(range.start, range_len(&range));
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if (rc == 0) {
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release_resource(data->res[i]);
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kfree(data->res[i]);
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data->res[i] = NULL;
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success++;
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continue;
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}
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any_hotremove_failed = true;
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dev_err(dev,
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"mapping%d: %#llx-%#llx cannot be hotremoved until the next reboot\n",
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i, range.start, range.end);
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}
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if (success >= dev_dax->nr_range) {
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memory_group_unregister(data->mgid);
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kfree(data->res_name);
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kfree(data);
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dev_set_drvdata(dev, NULL);
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/*
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* Clear the memtype association on successful unplug.
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* If not, we have memory blocks left which can be
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* offlined/onlined later. We need to keep memory_dev_type
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* for that. This implies this reference will be around
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* till next reboot.
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*/
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clear_node_memory_type(node, dax_slowmem_type);
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}
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}
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#else
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static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
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{
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/*
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* Without hotremove purposely leak the request_mem_region() for the
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* device-dax range and return '0' to ->remove() attempts. The removal
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* of the device from the driver always succeeds, but the region is
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* permanently pinned as reserved by the unreleased
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* request_mem_region().
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*/
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any_hotremove_failed = true;
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}
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#endif /* CONFIG_MEMORY_HOTREMOVE */
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static struct dax_device_driver device_dax_kmem_driver = {
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.probe = dev_dax_kmem_probe,
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.remove = dev_dax_kmem_remove,
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};
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static int __init dax_kmem_init(void)
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{
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int rc;
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/* Resource name is permanently allocated if any hotremove fails. */
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kmem_name = kstrdup_const("System RAM (kmem)", GFP_KERNEL);
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if (!kmem_name)
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return -ENOMEM;
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dax_slowmem_type = alloc_memory_type(MEMTIER_DEFAULT_DAX_ADISTANCE);
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if (IS_ERR(dax_slowmem_type)) {
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rc = PTR_ERR(dax_slowmem_type);
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goto err_dax_slowmem_type;
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}
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rc = dax_driver_register(&device_dax_kmem_driver);
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if (rc)
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goto error_dax_driver;
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return rc;
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error_dax_driver:
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destroy_memory_type(dax_slowmem_type);
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err_dax_slowmem_type:
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kfree_const(kmem_name);
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return rc;
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}
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static void __exit dax_kmem_exit(void)
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{
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dax_driver_unregister(&device_dax_kmem_driver);
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if (!any_hotremove_failed)
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kfree_const(kmem_name);
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destroy_memory_type(dax_slowmem_type);
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}
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MODULE_AUTHOR("Intel Corporation");
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MODULE_LICENSE("GPL v2");
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module_init(dax_kmem_init);
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module_exit(dax_kmem_exit);
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MODULE_ALIAS_DAX_DEVICE(0);
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