From nobody Thu Dec 18 05:40:24 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 15D69C61D97 for ; Wed, 22 Nov 2023 21:13:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344651AbjKVVNR (ORCPT ); Wed, 22 Nov 2023 16:13:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37068 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344654AbjKVVM5 (ORCPT ); Wed, 22 Nov 2023 16:12:57 -0500 Received: from mail-il1-x143.google.com (mail-il1-x143.google.com [IPv6:2607:f8b0:4864:20::143]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DE3D81732; Wed, 22 Nov 2023 13:12:38 -0800 (PST) Received: by mail-il1-x143.google.com with SMTP id e9e14a558f8ab-359d27f6d46so675435ab.3; Wed, 22 Nov 2023 13:12:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1700687558; x=1701292358; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=nj0/yLijkUDdchJx9f8WaqM9fNxYMjAKFnMHDPEdLR0=; b=CvLkIMDkDzteeQ6Ts+K4t3f+w6WGRk2D658wVs0Lj9UFMwobPY0HwrMsnMkXfyh3S9 VfilVD4qVHokHaRvnYM+cfsfPHXM0UKBl+S6ieVvv2BDzEWzmjo/8hqU9iffVFFi5WAt aX7QSfHXZWk5DBtsznxyMK47zYlulIPdgiY118oPBGWruuB1GMRLogc3boldj1f8MMbd QQJP9BwFKPKeUAsmkEF4J++KwT7cFA0Ol0bdjmpLM6cDl7DbKlEPls1CYBkG2qSkswVe g0Oz1Q35EkfceH9oFKpgdUZ/EUtwUaNlqyp9Hr/geiEwMpjnYQHn6PntfhiGXVq4+Wg+ bD1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700687558; x=1701292358; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=nj0/yLijkUDdchJx9f8WaqM9fNxYMjAKFnMHDPEdLR0=; b=MAZ2goqW4hMq6r9Qcpm+XCKoIiqUIiLtUj8mVwEPWJDgQmU8WS8sgZ9DLX2t7oC0jW wUd+eAwHNNoNKsLGIn9QD8+CxYE9eoXymZ+T6i1rzYURaygBJZnNfBjR9O8JaRJlrTYE DlzFkcurlb+hSTdryPfFBMUaYzh4++ZOLhpsH3hJi4q/Ot0ClUFsFxsWlkDBNabQEh4+ 3ILdX8qeGVvZAoqAUPDDpdQyQlq9+nCJqkgFtVirAzBKAKyI8V9QD1xIYJXTab8AdNGS QcAhuQXSm88JS4AbLx0PU8LKBkv60B2HQ00qOLSwXJnRD24omp2YRoup6w1gP5Vve0Wa g7Ug== X-Gm-Message-State: AOJu0Yy7Y18iohcUp0gv2YRtwWCUFBZ9cMx7GeOD+fm/q8Z+lgEVyz4G WPAA61Ogf3zWDS2wqrlS5Hz1N0Wfo8BX X-Google-Smtp-Source: AGHT+IGWypkgJaNcLXjK/eS64ds6ElauQ9WWQUmh33zgk8yVZiSbJ9XTKd3ElRdp4RxU4lnDOSLTsw== X-Received: by 2002:a05:6e02:1c84:b0:350:f51b:c32e with SMTP id w4-20020a056e021c8400b00350f51bc32emr4817949ill.16.1700687558122; Wed, 22 Nov 2023 13:12:38 -0800 (PST) Received: from fedora.mshome.net ([75.167.214.230]) by smtp.gmail.com with ESMTPSA id j18-20020a635512000000b005bdbce6818esm132136pgb.30.2023.11.22.13.12.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Nov 2023 13:12:37 -0800 (PST) From: Gregory Price X-Google-Original-From: Gregory Price To: linux-mm@kvack.org Cc: linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, arnd@arndb.de, tglx@linutronix.de, luto@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, mhocko@kernel.org, tj@kernel.org, ying.huang@intel.com, Gregory Price Subject: [RFC PATCH 11/11] fs/proc: Add mempolicy attribute to allow read/write of task mempolicy Date: Wed, 22 Nov 2023 16:12:00 -0500 Message-Id: <20231122211200.31620-12-gregory.price@memverge.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20231122211200.31620-1-gregory.price@memverge.com> References: <20231122211200.31620-1-gregory.price@memverge.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Expose mempolicy via procfs, and utilize the existing mpol_parse_str format to allow external tasks to change the policies of another task. mpol_parse_str format: [=3D][:] valid settings: "prefer" (without a nodemask, aliases to 'local') "prefer:node" "interleave:nodelist" "local" "default" "prefer (many):nodelist" "bind:nodelist" flags are either "=3Dstatic" or "=3Drelative", and cannot be used with "prefer" or "local" ("prefer=3Dflag:nodelist" is valid). Signed-off-by: Gregory Price --- fs/proc/Makefile | 1 + fs/proc/base.c | 1 + fs/proc/internal.h | 1 + fs/proc/mempolicy.c | 117 ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 120 insertions(+) create mode 100644 fs/proc/mempolicy.c diff --git a/fs/proc/Makefile b/fs/proc/Makefile index bd08616ed8ba..272d22d9022f 100644 --- a/fs/proc/Makefile +++ b/fs/proc/Makefile @@ -27,6 +27,7 @@ proc-y +=3D softirqs.o proc-y +=3D namespaces.o proc-y +=3D self.o proc-y +=3D thread_self.o +proc-y +=3D mempolicy.o proc-$(CONFIG_PROC_SYSCTL) +=3D proc_sysctl.o proc-$(CONFIG_NET) +=3D proc_net.o proc-$(CONFIG_PROC_KCORE) +=3D kcore.o diff --git a/fs/proc/base.c b/fs/proc/base.c index dd31e3b6bf77..3eb3d6d81a8e 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3279,6 +3279,7 @@ static const struct pid_entry tgid_base_stuff[] =3D { REG("maps", S_IRUGO, proc_pid_maps_operations), #ifdef CONFIG_NUMA REG("numa_maps", S_IRUGO, proc_pid_numa_maps_operations), + REG("mempolicy", S_IRUSR|S_IWUSR, proc_mempolicy_operations), #endif REG("mem", S_IRUSR|S_IWUSR, proc_mem_operations), LNK("cwd", proc_cwd_link), diff --git a/fs/proc/internal.h b/fs/proc/internal.h index 9a8f32f21ff5..e8e81629a8d8 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -303,6 +303,7 @@ extern const struct file_operations proc_pid_smaps_oper= ations; extern const struct file_operations proc_pid_smaps_rollup_operations; extern const struct file_operations proc_clear_refs_operations; extern const struct file_operations proc_pagemap_operations; +extern const struct file_operations proc_mempolicy_operations; =20 extern unsigned long task_vsize(struct mm_struct *); extern unsigned long task_statm(struct mm_struct *, diff --git a/fs/proc/mempolicy.c b/fs/proc/mempolicy.c new file mode 100644 index 000000000000..417c2c8046d9 --- /dev/null +++ b/fs/proc/mempolicy.c @@ -0,0 +1,117 @@ +// SPDX-License-Identifier: GPL-2.0 +#ifdef CONFIG_NUMA +#include +#include +#include +#include +#include +#include + +#include "internal.h" + +#define MPOL_STR_SIZE 4096 +static ssize_t mempolicy_read_proc(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + struct task_struct *task; + struct mempolicy *policy; + char *buffer; + ssize_t rv =3D 0; + size_t outlen; + + buffer =3D kzalloc(MPOL_STR_SIZE, GFP_KERNEL); + if (!buffer) + return -ENOMEM; + + task =3D get_proc_task(file_inode(file)); + if (!task) { + rv =3D -ESRCH; + goto freebuf; + } + + task_lock(task); + policy =3D get_task_policy(task); + mpol_get(policy); + task_unlock(task); + + if (!policy) + goto out; + + mpol_to_str(buffer, MPOL_STR_SIZE, policy); + + buffer[MPOL_STR_SIZE-1] =3D '\0'; + outlen =3D strlen(buffer); + if (outlen < MPOL_STR_SIZE - 1) { + buffer[outlen] =3D '\n'; + buffer[outlen + 1] =3D '\0'; + outlen++; + } + rv =3D simple_read_from_buffer(buf, count, ppos, buffer, outlen); + mpol_put(policy); +out: + put_task_struct(task); +freebuf: + kfree(buffer); + return rv; +} + +static ssize_t mempolicy_write_proc(struct file *file, const char __user *= buf, + size_t count, loff_t *ppos) +{ + struct task_struct *task; + struct mempolicy *new_policy =3D NULL; + char *mempolicy_str, *nl; + nodemask_t nodes; + int err; + + mempolicy_str =3D kmalloc(count + 1, GFP_KERNEL); + if (!mempolicy_str) + return -ENOMEM; + + if (copy_from_user(mempolicy_str, buf, count)) { + kfree(mempolicy_str); + return -EFAULT; + } + mempolicy_str[count] =3D '\0'; + + /* strip new line characters for simplicity of handling by parser */ + nl =3D strchr(mempolicy_str, '\n'); + if (nl) + *nl =3D '\0'; + nl =3D strchr(mempolicy_str, '\r'); + if (nl) + *nl =3D '\0'; + + err =3D mpol_parse_str(mempolicy_str, &new_policy); + if (err) { + kfree(mempolicy_str); + return err; + } + + /* If no error and no policy, it was 'default', clear node list */ + if (new_policy) + nodes =3D new_policy->nodes; + else + nodes_clear(nodes); + + task =3D get_proc_task(file_inode(file)); + if (!task) { + mpol_put(new_policy); + kfree(mempolicy_str); + return -ESRCH; + } + + err =3D replace_mempolicy(task, new_policy, &nodes); + + put_task_struct(task); + kfree(mempolicy_str); + + return err ? err : count; +} + +const struct file_operations proc_mempolicy_operations =3D { + .read =3D mempolicy_read_proc, + .write =3D mempolicy_write_proc, + .llseek =3D noop_llseek, +}; +#endif /* CONFIG_NUMA */ --=20 2.39.1