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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E688C433FE for ; Sat, 7 May 2022 01:43:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1389810AbiEGBrW (ORCPT ); Fri, 6 May 2022 21:47:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60908 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1445246AbiEGBrS (ORCPT ); Fri, 6 May 2022 21:47:18 -0400 Received: from mail-pg1-x52f.google.com (mail-pg1-x52f.google.com [IPv6:2607:f8b0:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E77C45DBC7; Fri, 6 May 2022 18:43:33 -0700 (PDT) Received: by mail-pg1-x52f.google.com with SMTP id 15so7429495pgf.4; Fri, 06 May 2022 18:43:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=xhp4PmSHzdcTg4X6br/SY/MgNKlnNiug+NCaOL77dg4=; b=TWXbumwiv7ccRTB0dmrhV4RFC6Mch/dZ2bQRWCxNrp7rKDulHfUmSbfczVIA/okp39 zmydRTRo9B+IiltF4aSIz2zw4K3gVW9mDXYtxUo4YrmGBn2gf2tOkyy3SwlPx2UAiYgT ceGnOVicntfQ6X7izFOSN9A63Niz+r3mEx0Ik1Gy6FOPHpI1LEaQTq6gNbRgQK8/Bvr7 jFy3ku9DqIe8S6xGO7PzrvE4x3uo+KCF4rUHAL6KvxHnylH7VpqpXbwxVwiE0ZPp8tkh YM7yNoL0+oHKeLZ5ydwhM4b68f3jVh52SX47vsc7eJghFnuCB7KikopVCBeW155kxe0m K7HA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=xhp4PmSHzdcTg4X6br/SY/MgNKlnNiug+NCaOL77dg4=; b=62JeJ1x5gr/VnAkgK+SB5VTQlxU6XE06j3niA6vVgT9oC7824JbWbJVg64hfapuylV 8D41WwiIg5toD53OUcc+0xhyEhcFteqXoNkq0260fLn5i2Kbvhy/nZSaIBz1tAByS2ZP i5KWIRXDVqmU4c0K/GiHtcqk36TQiiPw7GWEO5EL/PKGx9jfc3kgqlnhpG8PIw22ZoLB UHALrxT3kJlCbLDnnCgGqHJE2CrcXDbscCY+Tlx4fCG7/l4WEWQWn1ph0XDMpfqHZ+dh lUEVrIPLE2tSHJXXFRvaDzLEUocDHPW/Zsxb5mlRbyeSdNeLfN0NfsTrARu76evGNM2M Iltg== X-Gm-Message-State: AOAM531b1gMDAuYdXHygG4Pw+d0yQd7jr0oJ7FjngdP8yTp6B5EZKi1T 3gK6zmNAFolbKZehLSg4ojs= X-Google-Smtp-Source: ABdhPJw2WINuVYxwyjn4YtL6ag2cn2y/D6ysdRfB0zhZw3tC2yiWik0AIwNEnfKddQQuqGH9ndFEng== X-Received: by 2002:a65:6805:0:b0:3c1:bb28:6bd4 with SMTP id l5-20020a656805000000b003c1bb286bd4mr4997603pgt.585.1651887813423; Fri, 06 May 2022 18:43:33 -0700 (PDT) Received: from localhost.localdomain ([193.203.214.57]) by smtp.gmail.com with ESMTPSA id b141-20020a621b93000000b0050dc7628176sm3999189pfb.80.2022.05.06.18.43.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 May 2022 18:43:33 -0700 (PDT) From: cgel.zte@gmail.com X-Google-Original-From: xu.xin16@zte.com.cn To: akpm@linux-foundation.org Cc: keescook@chromium.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, xu xin , Yang Yang , Ran Xiaokai , wangyong , Yunkai Zhang Subject: [PATCH v2] mm/ksm: introduce ksm_force for each process Date: Sat, 7 May 2022 01:43:18 +0000 Message-Id: <20220507014318.642353-1-xu.xin16@zte.com.cn> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: xu xin To use KSM, we must explicitly call madvise() in application code, which means installed apps on OS needs to be uninstall and source code needs to be modified. It is inconvenient. In order to change this situation, We add a new proc 'ksm_force' under /proc// to support turning on/off KSM scanning of a process's mm dynamically. If ksm_force is set as 1, force all anonymous and 'qualified' vma of this mm to be involved in KSM scanning without explicitly calling madvise to make vma MADV_MERGEABLE. But It is effctive only when the klob of '/sys/kernel/mm/ksm/run' is set as 1. If ksm_enale is set as 0, cancel the feature of ksm_force of this process and unmerge those merged pages which is not madvised as MERGEABLE of this process, but leave MERGEABLE areas merged. Signed-off-by: xu xin Reviewed-by: Yang Yang Reviewed-by: Ran Xiaokai Reviewed-by: wangyong Reviewed-by: Yunkai Zhang --- v2: - fix a spelling error in commit log. - remove a redundant condition check in ksm_force_write(). --- fs/proc/base.c | 99 ++++++++++++++++++++++++++++++++++++++++ include/linux/mm_types.h | 9 ++++ mm/ksm.c | 32 ++++++++++++- 3 files changed, 138 insertions(+), 2 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 8dfa36a99c74..3115ffa4c9fb 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -96,6 +96,7 @@ #include #include #include +#include #include #include "internal.h" #include "fd.h" @@ -3168,6 +3169,102 @@ static int proc_pid_ksm_merging_pages(struct seq_file *m, struct pid_namespace * return 0; } + +static ssize_t ksm_force_read(struct file *file, char __user *buf, size_t count, + loff_t *ppos) +{ + struct task_struct *task; + struct mm_struct *mm; + char buffer[PROC_NUMBUF]; + ssize_t len; + int ret; + + task = get_proc_task(file_inode(file)); + if (!task) + return -ESRCH; + + mm = get_task_mm(task); + ret = 0; + if (mm) { + len = snprintf(buffer, sizeof(buffer), "%d\n", mm->ksm_force); + ret = simple_read_from_buffer(buf, count, ppos, buffer, len); + mmput(mm); + } + + return ret; +} + +static ssize_t ksm_force_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct task_struct *task; + struct mm_struct *mm; + char buffer[PROC_NUMBUF]; + int force; + int err = 0; + + memset(buffer, 0, sizeof(buffer)); + if (count > sizeof(buffer) - 1) + count = sizeof(buffer) - 1; + if (copy_from_user(buffer, buf, count)) { + err = -EFAULT; + goto out_return; + } + + err = kstrtoint(strstrip(buffer), 0, &force); + + if (err) + goto out_return; + if (force != 0 && force != 1) { + err = -EINVAL; + goto out_return; + } + + task = get_proc_task(file_inode(file)); + if (!task) { + err = -ESRCH; + goto out_return; + } + + mm = get_task_mm(task); + if (!mm) + goto out_put_task; + + if (mm->ksm_force != force) { + if (mmap_write_lock_killable(mm)) { + err = -EINTR; + goto out_mmput; + } + + if (force == 0) + mm->ksm_force = force; + else { + /* + * Force anonymous pages of this mm to be involved in KSM merging + * without explicitly calling madvise. + */ + if (!test_bit(MMF_VM_MERGEABLE, &mm->flags)) + err = __ksm_enter(mm); + if (!err) + mm->ksm_force = force; + } + + mmap_write_unlock(mm); + } + +out_mmput: + mmput(mm); +out_put_task: + put_task_struct(task); +out_return: + return err < 0 ? err : count; +} + +static const struct file_operations proc_pid_ksm_force_operations = { + .read = ksm_force_read, + .write = ksm_force_write, + .llseek = generic_file_llseek, +}; #endif /* CONFIG_KSM */ #ifdef CONFIG_STACKLEAK_METRICS @@ -3303,6 +3400,7 @@ static const struct pid_entry tgid_base_stuff[] = { #endif #ifdef CONFIG_KSM ONE("ksm_merging_pages", S_IRUSR, proc_pid_ksm_merging_pages), + REG("ksm_force", S_IRUSR|S_IWUSR, proc_pid_ksm_force_operations), #endif }; @@ -3639,6 +3737,7 @@ static const struct pid_entry tid_base_stuff[] = { #endif #ifdef CONFIG_KSM ONE("ksm_merging_pages", S_IRUSR, proc_pid_ksm_merging_pages), + REG("ksm_force", S_IRUSR|S_IWUSR, proc_pid_ksm_force_operations), #endif }; diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index b34ff2cdbc4f..1b1592c2f5cf 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -661,6 +661,15 @@ struct mm_struct { * merging. */ unsigned long ksm_merging_pages; + /* + * If true, force anonymous pages of this mm to be involved in KSM + * merging without explicitly calling madvise. It is effctive only + * when the klob of '/sys/kernel/mm/ksm/run' is set as 1. If false, + * cancel the feature of ksm_force of this process and unmerge + * those merged pages which is not madvised as MERGEABLE of this + * process, but leave MERGEABLE areas merged. + */ + bool ksm_force; #endif } __randomize_layout; diff --git a/mm/ksm.c b/mm/ksm.c index 38360285497a..ba170e53e283 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -334,6 +334,34 @@ static void __init ksm_slab_free(void) mm_slot_cache = NULL; } +/* Check if vma is qualified for ksmd scanning */ +static bool ksm_vma_check(struct vm_area_struct *vma) +{ + unsigned long vm_flags = vma->vm_flags; + + if (!(vma->vm_flags & VM_MERGEABLE) && !(vma->vm_mm->ksm_force)) + turn false; + + if (vm_flags & (VM_SHARED | VM_MAYSHARE | + VM_PFNMAP | VM_IO | VM_DONTEXPAND | + VM_HUGETLB | VM_MIXEDMAP)) + return false; /* just ignore this vma*/ + + if (vma_is_dax(vma)) + return false; + +#ifdef VM_SAO + if (vm_flags & VM_SAO) + return false; +#endif +#ifdef VM_SPARC_ADI + if (vm_flags & VM_SPARC_ADI) + return false; +#endif + + return true; +} + static __always_inline bool is_stable_node_chain(struct stable_node *chain) { return chain->rmap_hlist_len == STABLE_NODE_CHAIN; @@ -523,7 +551,7 @@ static struct vm_area_struct *find_mergeable_vma(struct mm_struct *mm, if (ksm_test_exit(mm)) return NULL; vma = vma_lookup(mm, addr); - if (!vma || !(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma) + if (!vma || !ksm_vma_check(vma) || !vma->anon_vma) return NULL; return vma; } @@ -2297,7 +2325,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page) vma = find_vma(mm, ksm_scan.address); for (; vma; vma = vma->vm_next) { - if (!(vma->vm_flags & VM_MERGEABLE)) + if (!ksm_vma_check(vma)) continue; if (ksm_scan.address < vma->vm_start) ksm_scan.address = vma->vm_start; -- 2.25.1