From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37B81C43444 for ; Thu, 17 Jan 2019 16:00:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E7B66205C9 for ; Thu, 17 Jan 2019 16:00:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547740839; bh=WgXeZ90IT68Tu4DHnaGsOWO3227RVXMiaL59JvcDd1M=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=ZekkFjcFjfZSm0mmbhasN7r112TX+NSsV40vMuWbVAkNadYZZ/QUkUsXMGWwWEyXv h6lIuUesUSV8NrYXOR1e9mVgqoTt9+RnoVXzfdYnCJjl0pYb28UHtHJeJAePcjsn7w 5SbB0hkkcfhtxMPFOOXeG3jOKuKcK0cNQqRr7fEw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728623AbfAQQAg (ORCPT ); Thu, 17 Jan 2019 11:00:36 -0500 Received: from mail-oi1-f173.google.com ([209.85.167.173]:45018 "EHLO mail-oi1-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727632AbfAQQAg (ORCPT ); Thu, 17 Jan 2019 11:00:36 -0500 Received: by mail-oi1-f173.google.com with SMTP id m6so6505965oig.11; Thu, 17 Jan 2019 08:00:35 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=rdu7kyWzYlUBD6Mskt8hw39fAw2nqx6mvnISETdM2jg=; b=PFlU4GNvgZXSu27KkjWfyL+vW0RB4PydewIfgVe0fFehnieIRQ1xaOqH5fKNO/r9PP P2r3aMc0Vp5RkmRZ6RvRAKoXJbBRc/xIXrxVHbdmdJcRgAw9oAu8GRKh8l6IeK/RVIFX vopD5oo1b5fsWvKeEXobjctTZuGTdGZCYMalDWr72pQWih7srgfyFQ/CDwXUibmEE8rd UjfciaDv2dCml2oYXgSy7UArODMFGPqc/tnWnCZK0UmviA4s3oABF9QTL9/xK7UwYbqP DIg+qHkmeOiUmjD6/aYPinbrsIy3SaZBS3Xwt6/g217876JPjSGMd5oRO/PmrwPikmDR BSsA== X-Gm-Message-State: AJcUukf3XRF+doBS0C25uLDINO4+y3NAbu47ltdMIprhcr2WITaGA8xM QPXni6TMuGCnh8yqvf/EY9zPMBYcewNPnBsIkIo= X-Google-Smtp-Source: ALg8bN5rxl9TkrG3mdMdexpWwg9jwTp3PTSfBUUlka/v5e8S62QOftTBtAbd9WNCisJH459t4ro18K14jCgIKQGCk00= X-Received: by 2002:aca:368a:: with SMTP id d132mr1877295oia.193.1547740834934; Thu, 17 Jan 2019 08:00:34 -0800 (PST) MIME-Version: 1.0 References: <20190116175804.30196-1-keith.busch@intel.com> <20190116175804.30196-11-keith.busch@intel.com> In-Reply-To: <20190116175804.30196-11-keith.busch@intel.com> From: "Rafael J. Wysocki" Date: Thu, 17 Jan 2019 17:00:23 +0100 Message-ID: Subject: Re: [PATCHv4 10/13] node: Add memory caching attributes To: Keith Busch Cc: Linux Kernel Mailing List , ACPI Devel Maling List , Linux Memory Management List , Greg Kroah-Hartman , Rafael Wysocki , Dave Hansen , Dan Williams Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 16, 2019 at 6:59 PM Keith Busch wrote: > > 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 > --- > 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; I would add an empty line here. > +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); I'd suggest using dev_dbg() for this and I'm not even sure if printing the message is worth the effort. Firmware will probably give you duplicates and users cannot do much about fixing that anyway. > + 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; Again, I'd add an empty line here. > +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) > +{ > +} And does this really build with CONFIG_HMEM_REPORTING unset? > #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; > --