Hello Keith Could we ever have a single side cache in front of two NUMA nodes ? I don't see a way to find that out in the current implementation. Would we have an "id" and/or "nodemap" bitmask in the sidecache structure ?
Thanks Brice Le 16/01/2019 à 18:58, Keith Busch a écrit : > System memory may have side caches to help improve access speed to > frequently requested address ranges. While the system provided cache is > transparent to the software accessing these memory ranges, applications > can optimize their own access based on cache attributes. > > Provide a new API for the kernel to register these memory side caches > under the memory node that provides it. > > The new sysfs representation is modeled from the existing cpu cacheinfo > attributes, as seen from /sys/devices/system/cpu/cpuX/side_cache/. > Unlike CPU cacheinfo, though, the node cache level is reported from > the view of the memory. A higher number is nearer to the CPU, while > lower levels are closer to the backing memory. Also unlike CPU cache, > it is assumed the system will handle flushing any dirty cached memory > to the last level on a power failure if the range is persistent memory. > > The attributes we export are the cache size, the line size, associativity, > and write back policy. > > Signed-off-by: Keith Busch <[email protected]> > --- > drivers/base/node.c | 142 > +++++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/node.h | 39 ++++++++++++++ > 2 files changed, 181 insertions(+) > > diff --git a/drivers/base/node.c b/drivers/base/node.c > index 1e909f61e8b1..7ff3ed566d7d 100644 > --- a/drivers/base/node.c > +++ b/drivers/base/node.c > @@ -191,6 +191,146 @@ void node_set_perf_attrs(unsigned int nid, struct > node_hmem_attrs *hmem_attrs, > pr_info("failed to add performance attribute group to node > %d\n", > nid); > } > + > +struct node_cache_info { > + struct device dev; > + struct list_head node; > + struct node_cache_attrs cache_attrs; > +}; > +#define to_cache_info(device) container_of(device, struct node_cache_info, > dev) > + > +#define CACHE_ATTR(name, fmt) > \ > +static ssize_t name##_show(struct device *dev, > \ > + struct device_attribute *attr, \ > + char *buf) \ > +{ \ > + return sprintf(buf, fmt "\n", to_cache_info(dev)->cache_attrs.name);\ > +} \ > +DEVICE_ATTR_RO(name); > + > +CACHE_ATTR(size, "%llu") > +CACHE_ATTR(level, "%u") > +CACHE_ATTR(line_size, "%u") > +CACHE_ATTR(associativity, "%u") > +CACHE_ATTR(write_policy, "%u") > + > +static struct attribute *cache_attrs[] = { > + &dev_attr_level.attr, > + &dev_attr_associativity.attr, > + &dev_attr_size.attr, > + &dev_attr_line_size.attr, > + &dev_attr_write_policy.attr, > + NULL, > +}; > +ATTRIBUTE_GROUPS(cache); > + > +static void node_cache_release(struct device *dev) > +{ > + kfree(dev); > +} > + > +static void node_cacheinfo_release(struct device *dev) > +{ > + struct node_cache_info *info = to_cache_info(dev); > + kfree(info); > +} > + > +static void node_init_cache_dev(struct node *node) > +{ > + struct device *dev; > + > + dev = kzalloc(sizeof(*dev), GFP_KERNEL); > + if (!dev) > + return; > + > + dev->parent = &node->dev; > + dev->release = node_cache_release; > + if (dev_set_name(dev, "side_cache")) > + goto free_dev; > + > + if (device_register(dev)) > + goto free_name; > + > + pm_runtime_no_callbacks(dev); > + node->cache_dev = dev; > + return; > +free_name: > + kfree_const(dev->kobj.name); > +free_dev: > + kfree(dev); > +} > + > +void node_add_cache(unsigned int nid, struct node_cache_attrs *cache_attrs) > +{ > + struct node_cache_info *info; > + struct device *dev; > + struct node *node; > + > + if (!node_online(nid) || !node_devices[nid]) > + return; > + > + node = node_devices[nid]; > + list_for_each_entry(info, &node->cache_attrs, node) { > + if (info->cache_attrs.level == cache_attrs->level) { > + dev_warn(&node->dev, > + "attempt to add duplicate cache level:%d\n", > + cache_attrs->level); > + return; > + } > + } > + > + if (!node->cache_dev) > + node_init_cache_dev(node); > + if (!node->cache_dev) > + return; > + > + info = kzalloc(sizeof(*info), GFP_KERNEL); > + if (!info) > + return; > + > + dev = &info->dev; > + dev->parent = node->cache_dev; > + dev->release = node_cacheinfo_release; > + dev->groups = cache_groups; > + if (dev_set_name(dev, "index%d", cache_attrs->level)) > + goto free_cache; > + > + info->cache_attrs = *cache_attrs; > + if (device_register(dev)) { > + dev_warn(&node->dev, "failed to add cache level:%d\n", > + cache_attrs->level); > + goto free_name; > + } > + pm_runtime_no_callbacks(dev); > + list_add_tail(&info->node, &node->cache_attrs); > + return; > +free_name: > + kfree_const(dev->kobj.name); > +free_cache: > + kfree(info); > +} > + > +static void node_remove_caches(struct node *node) > +{ > + struct node_cache_info *info, *next; > + > + if (!node->cache_dev) > + return; > + > + list_for_each_entry_safe(info, next, &node->cache_attrs, node) { > + list_del(&info->node); > + device_unregister(&info->dev); > + } > + device_unregister(node->cache_dev); > +} > + > +static void node_init_caches(unsigned int nid) > +{ > + INIT_LIST_HEAD(&node_devices[nid]->cache_attrs); > +} > +#else > +static void node_init_caches(unsigned int nid) { } > +static void node_remove_caches(struct node *node) { } > #endif > > #define K(x) ((x) << (PAGE_SHIFT - 10)) > @@ -475,6 +615,7 @@ void unregister_node(struct node *node) > { > hugetlb_unregister_node(node); /* no-op, if memoryless node */ > node_remove_classes(node); > + node_remove_caches(node); > device_unregister(&node->dev); > } > > @@ -755,6 +896,7 @@ int __register_one_node(int nid) > INIT_LIST_HEAD(&node_devices[nid]->class_list); > /* initialize work queue for memory hot plug */ > init_node_hugetlb_work(nid); > + node_init_caches(nid); > > return error; > } > diff --git a/include/linux/node.h b/include/linux/node.h > index e22940a593c2..8cdf2b2808e4 100644 > --- a/include/linux/node.h > +++ b/include/linux/node.h > @@ -37,12 +37,47 @@ struct node_hmem_attrs { > }; > void node_set_perf_attrs(unsigned int nid, struct node_hmem_attrs > *hmem_attrs, > unsigned class); > + > +enum cache_associativity { > + NODE_CACHE_DIRECT_MAP, > + NODE_CACHE_INDEXED, > + NODE_CACHE_OTHER, > +}; > + > +enum cache_write_policy { > + NODE_CACHE_WRITE_BACK, > + NODE_CACHE_WRITE_THROUGH, > + NODE_CACHE_WRITE_OTHER, > +}; > + > +/** > + * struct node_cache_attrs - system memory caching attributes > + * > + * @associativity: The ways memory blocks may be placed in cache > + * @write_policy: Write back or write through policy > + * @size: Total size of cache in bytes > + * @line_size: Number of bytes fetched on a cache miss > + * @level: Represents the cache hierarchy level > + */ > +struct node_cache_attrs { > + enum cache_associativity associativity; > + enum cache_write_policy write_policy; > + u64 size; > + u16 line_size; > + u8 level; > +}; > +void node_add_cache(unsigned int nid, struct node_cache_attrs *cache_attrs); > #else > static inline void node_set_perf_attrs(unsigned int nid, > struct node_hmem_attrs *hmem_attrs, > unsigned class) > { > } > + > +static inline void node_add_cache(unsigned int nid, > + struct node_cache_attrs *cache_attrs) > +{ > +} > #endif > > struct node { > @@ -51,6 +86,10 @@ struct node { > #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS) > struct work_struct node_work; > #endif > +#ifdef CONFIG_HMEM_REPORTING > + struct list_head cache_attrs; > + struct device *cache_dev; > +#endif > }; > > struct memory_block;
