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[173.79.56.208]) by smtp.gmail.com with ESMTPSA id z22-20020aa785d6000000b006ddddc7701fsm1866578pfn.4.2024.02.02.09.02.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Feb 2024 09:02:48 -0800 (PST) From: Gregory Price X-Google-Original-From: Gregory Price To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, corbet@lwn.net, akpm@linux-foundation.org, gregory.price@memverge.com, honggyu.kim@sk.com, rakie.kim@sk.com, hyeongtak.ji@sk.com, mhocko@kernel.org, ying.huang@intel.com, vtavarespetr@micron.com, jgroves@micron.com, ravis.opensrc@micron.com, sthanneeru@micron.com, emirakhur@micron.com, Hasan.Maruf@amd.com, seungjun.ha@samsung.com, hannes@cmpxchg.org, dan.j.williams@intel.com Subject: [PATCH v5 1/4] mm/mempolicy: implement the sysfs-based weighted_interleave interface Date: Fri, 2 Feb 2024 12:02:35 -0500 Message-Id: <20240202170238.90004-2-gregory.price@memverge.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20240202170238.90004-1-gregory.price@memverge.com> References: <20240202170238.90004-1-gregory.price@memverge.com> MIME-Version: 1.0 X-Rspam-User: X-Stat-Signature: iaws31mr843m5cwg3gh9qbn1io636kbq X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: AF5524002F X-HE-Tag: 1706893370-310142 X-HE-Meta: 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 wVMGFgD9 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Rakie Kim This patch provides a way to set interleave weight information under sysfs at /sys/kernel/mm/mempolicy/weighted_interleave/nodeN The sysfs structure is designed as follows. $ tree /sys/kernel/mm/mempolicy/ /sys/kernel/mm/mempolicy/ [1] └── weighted_interleave [2] ├── node0 [3] └── node1 Each file above can be explained as follows. [1] mm/mempolicy: configuration interface for mempolicy subsystem [2] weighted_interleave/: config interface for weighted interleave policy [3] weighted_interleave/nodeN: weight for nodeN If a node value is set to `0`, the system-default value will be used. As of this patch, the system-default for all nodes is always 1. Suggested-by: "Huang, Ying" Signed-off-by: Rakie Kim Signed-off-by: Honggyu Kim Co-developed-by: Gregory Price Signed-off-by: Gregory Price Co-developed-by: Hyeongtak Ji Signed-off-by: Hyeongtak Ji Reviewed-by: "Huang, Ying" --- .../ABI/testing/sysfs-kernel-mm-mempolicy | 4 + ...fs-kernel-mm-mempolicy-weighted-interleave | 25 ++ mm/mempolicy.c | 223 ++++++++++++++++++ 3 files changed, 252 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-kernel-mm-mempolicy create mode 100644 Documentation/ABI/testing/sysfs-kernel-mm-mempolicy-weighted-interleave diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-mempolicy b/Documentation/ABI/testing/sysfs-kernel-mm-mempolicy new file mode 100644 index 000000000000..8ac327fd7fb6 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-mm-mempolicy @@ -0,0 +1,4 @@ +What: /sys/kernel/mm/mempolicy/ +Date: January 2024 +Contact: Linux memory management mailing list +Description: Interface for Mempolicy diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-mempolicy-weighted-interleave b/Documentation/ABI/testing/sysfs-kernel-mm-mempolicy-weighted-interleave new file mode 100644 index 000000000000..0b7972de04e9 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-mm-mempolicy-weighted-interleave @@ -0,0 +1,25 @@ +What: /sys/kernel/mm/mempolicy/weighted_interleave/ +Date: January 2024 +Contact: Linux memory management mailing list +Description: Configuration Interface for the Weighted Interleave policy + +What: /sys/kernel/mm/mempolicy/weighted_interleave/nodeN +Date: January 2024 +Contact: Linux memory management mailing list +Description: Weight configuration interface for nodeN + + The interleave weight for a memory node (N). These weights are + utilized by tasks which have set their mempolicy to + MPOL_WEIGHTED_INTERLEAVE. + + These weights only affect new allocations, and changes at runtime + will not cause migrations on already allocated pages. + + The minimum weight for a node is always 1. + + Minimum weight: 1 + Maximum weight: 255 + + Writing an empty string or `0` will reset the weight to the + system default. The system default may be set by the kernel + or drivers at boot or during hotplug events. diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 10a590ee1c89..41e58c4c0d01 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -131,6 +131,32 @@ static struct mempolicy default_policy = { static struct mempolicy preferred_node_policy[MAX_NUMNODES]; +/* + * iw_table is the sysfs-set interleave weight table, a value of 0 denotes + * system-default value should be used. A NULL iw_table also denotes that + * system-default values should be used. Until the system-default table + * is implemented, the system-default is always 1. + * + * iw_table is RCU protected + */ +static u8 __rcu *iw_table; +static DEFINE_MUTEX(iw_table_lock); + +static u8 get_il_weight(int node) +{ + u8 *table; + u8 weight; + + rcu_read_lock(); + table = rcu_dereference(iw_table); + /* if no iw_table, use system default */ + weight = table ? table[node] : 1; + /* if value in iw_table is 0, use system default */ + weight = weight ? weight : 1; + rcu_read_unlock(); + return weight; +} + /** * numa_nearest_node - Find nearest node by state * @node: Node id to start the search @@ -3067,3 +3093,200 @@ void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol) p += scnprintf(p, buffer + maxlen - p, ":%*pbl", nodemask_pr_args(&nodes)); } + +#ifdef CONFIG_SYSFS +struct iw_node_attr { + struct kobj_attribute kobj_attr; + int nid; +}; + +static ssize_t node_show(struct kobject *kobj, struct kobj_attribute *attr, + char *buf) +{ + struct iw_node_attr *node_attr; + u8 weight; + + node_attr = container_of(attr, struct iw_node_attr, kobj_attr); + weight = get_il_weight(node_attr->nid); + return sysfs_emit(buf, "%d\n", weight); +} + +static ssize_t node_store(struct kobject *kobj, struct kobj_attribute *attr, + const char *buf, size_t count) +{ + struct iw_node_attr *node_attr; + u8 *new; + u8 *old; + u8 weight = 0; + + node_attr = container_of(attr, struct iw_node_attr, kobj_attr); + if (count == 0 || sysfs_streq(buf, "")) + weight = 0; + else if (kstrtou8(buf, 0, &weight)) + return -EINVAL; + + new = kzalloc(nr_node_ids, GFP_KERNEL); + if (!new) + return -ENOMEM; + + mutex_lock(&iw_table_lock); + old = rcu_dereference_protected(iw_table, + lockdep_is_held(&iw_table_lock)); + if (old) + memcpy(new, old, nr_node_ids); + new[node_attr->nid] = weight; + rcu_assign_pointer(iw_table, new); + mutex_unlock(&iw_table_lock); + synchronize_rcu(); + kfree(old); + return count; +} + +static struct iw_node_attr **node_attrs; + +static void sysfs_wi_node_release(struct iw_node_attr *node_attr, + struct kobject *parent) +{ + if (!node_attr) + return; + sysfs_remove_file(parent, &node_attr->kobj_attr.attr); + kfree(node_attr->kobj_attr.attr.name); + kfree(node_attr); +} + +static void sysfs_wi_release(struct kobject *wi_kobj) +{ + int i; + + for (i = 0; i < nr_node_ids; i++) + sysfs_wi_node_release(node_attrs[i], wi_kobj); + kobject_put(wi_kobj); +} + +static const struct kobj_type wi_ktype = { + .sysfs_ops = &kobj_sysfs_ops, + .release = sysfs_wi_release, +}; + +static int add_weight_node(int nid, struct kobject *wi_kobj) +{ + struct iw_node_attr *node_attr; + char *name; + + node_attr = kzalloc(sizeof(*node_attr), GFP_KERNEL); + if (!node_attr) + return -ENOMEM; + + name = kasprintf(GFP_KERNEL, "node%d", nid); + if (!name) { + kfree(node_attr); + return -ENOMEM; + } + + sysfs_attr_init(&node_attr->kobj_attr.attr); + node_attr->kobj_attr.attr.name = name; + node_attr->kobj_attr.attr.mode = 0644; + node_attr->kobj_attr.show = node_show; + node_attr->kobj_attr.store = node_store; + node_attr->nid = nid; + + if (sysfs_create_file(wi_kobj, &node_attr->kobj_attr.attr)) { + kfree(node_attr->kobj_attr.attr.name); + kfree(node_attr); + pr_err("failed to add attribute to weighted_interleave\n"); + return -ENOMEM; + } + + node_attrs[nid] = node_attr; + return 0; +} + +static int add_weighted_interleave_group(struct kobject *root_kobj) +{ + struct kobject *wi_kobj; + int nid, err; + + wi_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL); + if (!wi_kobj) + return -ENOMEM; + + err = kobject_init_and_add(wi_kobj, &wi_ktype, root_kobj, + "weighted_interleave"); + if (err) { + kfree(wi_kobj); + return err; + } + + for_each_node_state(nid, N_POSSIBLE) { + err = add_weight_node(nid, wi_kobj); + if (err) { + pr_err("failed to add sysfs [node%d]\n", nid); + break; + } + } + if (err) + kobject_put(wi_kobj); + return 0; +} + +static void mempolicy_kobj_release(struct kobject *kobj) +{ + u8 *old; + + mutex_lock(&iw_table_lock); + old = rcu_dereference_protected(iw_table, + lockdep_is_held(&iw_table_lock)); + rcu_assign_pointer(iw_table, NULL); + mutex_unlock(&iw_table_lock); + synchronize_rcu(); + kfree(old); + kfree(node_attrs); + kfree(kobj); +} + +static const struct kobj_type mempolicy_ktype = { + .release = mempolicy_kobj_release +}; + +static int __init mempolicy_sysfs_init(void) +{ + int err; + static struct kobject *mempolicy_kobj; + + mempolicy_kobj = kzalloc(sizeof(*mempolicy_kobj), GFP_KERNEL); + if (!mempolicy_kobj) { + err = -ENOMEM; + goto err_out; + } + + node_attrs = kcalloc(nr_node_ids, sizeof(struct iw_node_attr *), + GFP_KERNEL); + if (!node_attrs) { + err = -ENOMEM; + goto mempol_out; + } + + err = kobject_init_and_add(mempolicy_kobj, &mempolicy_ktype, mm_kobj, + "mempolicy"); + if (err) + goto node_out; + + err = add_weighted_interleave_group(mempolicy_kobj); + if (err) { + pr_err("mempolicy sysfs structure failed to initialize\n"); + kobject_put(mempolicy_kobj); + return err; + } + + return err; +node_out: + kfree(node_attrs); +mempol_out: + kfree(mempolicy_kobj); +err_out: + pr_err("failed to add mempolicy kobject to the system\n"); + return err; +} + +late_initcall(mempolicy_sysfs_init); 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[173.79.56.208]) by smtp.gmail.com with ESMTPSA id z22-20020aa785d6000000b006ddddc7701fsm1866578pfn.4.2024.02.02.09.02.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Feb 2024 09:02:52 -0800 (PST) From: Gregory Price X-Google-Original-From: Gregory Price To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, corbet@lwn.net, akpm@linux-foundation.org, gregory.price@memverge.com, honggyu.kim@sk.com, rakie.kim@sk.com, hyeongtak.ji@sk.com, mhocko@kernel.org, ying.huang@intel.com, vtavarespetr@micron.com, jgroves@micron.com, ravis.opensrc@micron.com, sthanneeru@micron.com, emirakhur@micron.com, Hasan.Maruf@amd.com, seungjun.ha@samsung.com, hannes@cmpxchg.org, dan.j.williams@intel.com Subject: [PATCH v5 2/4] mm/mempolicy: refactor a read-once mechanism into a function for re-use Date: Fri, 2 Feb 2024 12:02:36 -0500 Message-Id: <20240202170238.90004-3-gregory.price@memverge.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20240202170238.90004-1-gregory.price@memverge.com> References: <20240202170238.90004-1-gregory.price@memverge.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: AF1B6140022 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: fooqj3136dnqzby3ng51saen11usmw8s X-HE-Tag: 1706893374-726036 X-HE-Meta: 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 ODScTzzY 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: move the use of barrier() to force policy->nodemask onto the stack into a function `read_once_policy_nodemask` so that it may be re-used. Suggested-by: "Huang, Ying" Signed-off-by: Gregory Price Reviewed-by: "Huang, Ying" --- mm/mempolicy.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 41e58c4c0d01..697f2a791c24 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1909,6 +1909,20 @@ unsigned int mempolicy_slab_node(void) } } +static unsigned int read_once_policy_nodemask(struct mempolicy *pol, + nodemask_t *mask) +{ + /* + * barrier stabilizes the nodemask locally so that it can be iterated + * over safely without concern for changes. Allocators validate node + * selection does not violate mems_allowed, so this is safe. + */ + barrier(); + memcpy(mask, &pol->nodes, sizeof(nodemask_t)); + barrier(); + return nodes_weight(*mask); +} + /* * Do static interleaving for interleave index @ilx. Returns the ilx'th * node in pol->nodes (starting from ilx=0), wrapping around if ilx @@ -1916,20 +1930,12 @@ unsigned int mempolicy_slab_node(void) */ static unsigned int interleave_nid(struct mempolicy *pol, pgoff_t ilx) { - nodemask_t nodemask = pol->nodes; + nodemask_t nodemask; unsigned int target, nnodes; int i; int nid; - /* - * The barrier will stabilize the nodemask in a register or on - * the stack so that it will stop changing under the code. - * - * Between first_node() and next_node(), pol->nodes could be changed - * by other threads. So we put pol->nodes in a local stack. - */ - barrier(); - nnodes = nodes_weight(nodemask); + nnodes = read_once_policy_nodemask(pol, &nodemask); if (!nnodes) return numa_node_id(); target = ilx % nnodes; From patchwork Fri Feb 2 17:02:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gregory Price X-Patchwork-Id: 13543171 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 72E57C4828F for ; Fri, 2 Feb 2024 17:03:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F1E2A6B007D; Fri, 2 Feb 2024 12:03:04 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EA7126B007E; Fri, 2 Feb 2024 12:03:04 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D206C6B0080; 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[173.79.56.208]) by smtp.gmail.com with ESMTPSA id z22-20020aa785d6000000b006ddddc7701fsm1866578pfn.4.2024.02.02.09.02.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Feb 2024 09:03:00 -0800 (PST) From: Gregory Price X-Google-Original-From: Gregory Price To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, corbet@lwn.net, akpm@linux-foundation.org, gregory.price@memverge.com, honggyu.kim@sk.com, rakie.kim@sk.com, hyeongtak.ji@sk.com, mhocko@kernel.org, ying.huang@intel.com, vtavarespetr@micron.com, jgroves@micron.com, ravis.opensrc@micron.com, sthanneeru@micron.com, emirakhur@micron.com, Hasan.Maruf@amd.com, seungjun.ha@samsung.com, hannes@cmpxchg.org, dan.j.williams@intel.com Subject: [PATCH v5 4/4] mm/mempolicy: protect task interleave functions with tsk->mems_allowed_seq Date: Fri, 2 Feb 2024 12:02:38 -0500 Message-Id: <20240202170238.90004-5-gregory.price@memverge.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20240202170238.90004-1-gregory.price@memverge.com> References: <20240202170238.90004-1-gregory.price@memverge.com> MIME-Version: 1.0 X-Rspam-User: X-Stat-Signature: t88omebkxczey9p1dbnhp1nphz4z94i4 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 6DB6414001D X-HE-Tag: 1706893382-514623 X-HE-Meta: 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 ZF1M7/eA 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: In the event of rebind, pol->nodemask can change at the same time as an allocation occurs. We can detect this with tsk->mems_allowed_seq and prevent a miscount or an allocation failure from occurring. The same thing happens in the allocators to detect failure, but this can prevent spurious failures in a much smaller critical section. Suggested-by: "Huang, Ying" Signed-off-by: Gregory Price --- mm/mempolicy.c | 31 +++++++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index d8cc3a577986..ed0d5d2d456a 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1878,11 +1878,17 @@ bool apply_policy_zone(struct mempolicy *policy, enum zone_type zone) static unsigned int weighted_interleave_nodes(struct mempolicy *policy) { - unsigned int node = current->il_prev; - - if (!current->il_weight || !node_isset(node, policy->nodes)) { + unsigned int node; + unsigned int cpuset_mems_cookie; + +retry: + /* to prevent miscount use tsk->mems_allowed_seq to detect rebind */ + cpuset_mems_cookie = read_mems_allowed_begin(); + node = current->il_prev; + if (!node || !node_isset(node, policy->nodes)) { node = next_node_in(node, policy->nodes); - /* can only happen if nodemask is being rebound */ + if (read_mems_allowed_retry(cpuset_mems_cookie)) + goto retry; if (node == MAX_NUMNODES) return node; current->il_prev = node; @@ -1896,8 +1902,14 @@ static unsigned int weighted_interleave_nodes(struct mempolicy *policy) static unsigned int interleave_nodes(struct mempolicy *policy) { unsigned int nid; + unsigned int cpuset_mems_cookie; + + /* to prevent miscount, use tsk->mems_allowed_seq to detect rebind */ + do { + cpuset_mems_cookie = read_mems_allowed_begin(); + nid = next_node_in(current->il_prev, policy->nodes); + } while (read_mems_allowed_retry(cpuset_mems_cookie)); - nid = next_node_in(current->il_prev, policy->nodes); if (nid < MAX_NUMNODES) current->il_prev = nid; return nid; @@ -2374,6 +2386,7 @@ static unsigned long alloc_pages_bulk_array_weighted_interleave(gfp_t gfp, struct page **page_array) { struct task_struct *me = current; + unsigned int cpuset_mems_cookie; unsigned long total_allocated = 0; unsigned long nr_allocated = 0; unsigned long rounds; @@ -2391,7 +2404,13 @@ static unsigned long alloc_pages_bulk_array_weighted_interleave(gfp_t gfp, if (!nr_pages) return 0; - nnodes = read_once_policy_nodemask(pol, &nodes); + /* read the nodes onto the stack, retry if done during rebind */ + do { + cpuset_mems_cookie = read_mems_allowed_begin(); + nnodes = read_once_policy_nodemask(pol, &nodes); + } while (read_mems_allowed_retry(cpuset_mems_cookie)); + + /* if the nodemask has become invalid, we cannot do anything */ if (!nnodes) return 0;