From patchwork Tue Jun 13 03:09:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Yang X-Patchwork-Id: 107049 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:994d:0:b0:3d9:f83d:47d9 with SMTP id k13csp274332vqr; Mon, 12 Jun 2023 20:15:48 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ72gI2SKiImVW/VQ82iSds3jTLUSjLokwo9hIwdzQhzOp0kDsUTHFY7ZtfisfC+uyX0U9tj X-Received: by 2002:a17:907:928a:b0:973:940e:a01d with SMTP id bw10-20020a170907928a00b00973940ea01dmr13009782ejc.67.1686626147981; Mon, 12 Jun 2023 20:15:47 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1686626147; cv=none; d=google.com; s=arc-20160816; b=aZOx8m4nXtkolF9AvL0D+6sXTIVcZ2IBFqThk+KjkUD/s7yd04Tbp3IX5BHezkL/vZ Qpa+rGdAnkw12lmNySzdKzZ/+FtsA6vyIb+vIoCQhyjrNvO2vR3ePfDenTFlZnc5voTW ZmhtmP4MnqRhsaKr1Jn+nOGUWHah7tth7h6OANscdqfm7NHSwUs3nRTcgAHh65814RNx SSkXDv1WfI8oNMb2w8jTivTS/sSI+JZXwdG0OsXN3VDTrWIiNxWcvdmequ4vuhqCQjPY By8E2eYpxYAIBVm+cKy1OK/v4ffp3cXPnc4VuGsCyBG9noC2pcY8PSowywSn1gP7nZ91 Z/cg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=kCQUTeUP3ROQYZtPgyjuZCT/GfWbGU8BjzTa96ma1MM=; b=wbVKt1GX55kvJ9XX6ayqO89AZBBUvpPx1D1CZ0IrfOzTNA5Yjn+rCXYk9xV/C0InoG Ypf7SthzPX/hL7wg1cIZOOoYeAo3x6ZaxgegW045+G7NIKo+xlOv9cxuU2n0uUrKDSiO /HTc1nyw+SDdcJI1iXGNpOXvxv/Fb1o8xWRxZEoYoGr8XtreDvT65c3w4NCObgqSELJm w3rrorkYo7so/ETM40v7aXqax0Mefri1erSCz+VXbNtabw7Aa3lBK56TVubTxxgrGUgw 31OuHbvrCPsRDDvbUFL4Kvewpwu20KhTCMM9fRBj+c0fJuEcGvX3O/tC2Ams0k0+Q4u8 rUpA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=zte.com.cn Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id a27-20020a170906245b00b00978923794d4si3096386ejb.554.2023.06.12.20.15.23; Mon, 12 Jun 2023 20:15:47 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=zte.com.cn Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235134AbjFMDLl (ORCPT + 99 others); Mon, 12 Jun 2023 23:11:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240428AbjFMDLG (ORCPT ); Mon, 12 Jun 2023 23:11:06 -0400 Received: from ubuntu20 (unknown [193.203.214.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 16D5CF9 for ; Mon, 12 Jun 2023 20:09:32 -0700 (PDT) Received: by ubuntu20 (Postfix, from userid 1003) id 79561E2295; Tue, 13 Jun 2023 11:09:31 +0800 (CST) From: Yang Yang To: akpm@linux-foundation.org, david@redhat.com Cc: yang.yang29@zte.com.cn, imbrenda@linux.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ran.xiaokai@zte.com.cn, xu.xin.sc@gmail.com, xu.xin16@zte.com.cn, Xuexin Jiang Subject: [PATCH RESEND v10 1/5] ksm: support unsharing KSM-placed zero pages Date: Tue, 13 Jun 2023 11:09:28 +0800 Message-Id: <20230613030928.185882-1-yang.yang29@zte.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: <202306131104554703428@zte.com.cn> References: <202306131104554703428@zte.com.cn> MIME-Version: 1.0 X-Spam-Status: No, score=3.4 required=5.0 tests=BAYES_00, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,FSL_HELO_NON_FQDN_1, HEADER_FROM_DIFFERENT_DOMAINS,HELO_NO_DOMAIN,NO_DNS_FOR_FROM, RCVD_IN_PBL,RDNS_NONE,SPF_SOFTFAIL,SPOOFED_FREEMAIL_NO_RDNS, T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Level: *** X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1768555699809767281?= X-GMAIL-MSGID: =?utf-8?q?1768555699809767281?= From: xu xin When use_zero_pages of ksm is enabled, madvise(addr, len, MADV_UNMERGEABLE) and other ways (like write 2 to /sys/kernel/mm/ksm/run) to trigger unsharing will *not* actually unshare the shared zeropage as placed by KSM (which is against the MADV_UNMERGEABLE documentation). As these KSM-placed zero pages are out of the control of KSM, the related counts of ksm pages don't expose how many zero pages are placed by KSM (these special zero pages are different from those initially mapped zero pages, because the zero pages mapped to MADV_UNMERGEABLE areas are expected to be a complete and unshared page). To not blindly unshare all shared zero_pages in applicable VMAs, the patch use pte_mkdirty (related with architecture) to mark KSM-placed zero pages. Thus, MADV_UNMERGEABLE will only unshare those KSM-placed zero pages. In addition, we'll reuse this mechanism to reliably identify KSM-placed ZeroPages to properly account for them (e.g., calculating the KSM profit that includes zeropages) in the latter patches. The patch will not degrade the performance of use_zero_pages as it doesn't change the way of merging empty pages in use_zero_pages's feature. Signed-off-by: xu xin Acked-by: David Hildenbrand Cc: Claudio Imbrenda Cc: Xuexin Jiang Reviewed-by: Xiaokai Ran Reviewed-by: Yang Yang --- include/linux/ksm.h | 6 ++++++ mm/ksm.c | 11 ++++++++--- 2 files changed, 14 insertions(+), 3 deletions(-) diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 899a314bc487..98878107244f 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -26,6 +26,12 @@ int ksm_disable(struct mm_struct *mm); int __ksm_enter(struct mm_struct *mm); void __ksm_exit(struct mm_struct *mm); +/* + * To identify zeropages that were mapped by KSM, we reuse the dirty bit + * in the PTE. If the PTE is dirty, the zeropage was mapped by KSM when + * deduplicating memory. + */ +#define is_ksm_zero_pte(pte) (is_zero_pfn(pte_pfn(pte)) && pte_dirty(pte)) static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) { diff --git a/mm/ksm.c b/mm/ksm.c index 0156bded3a66..f31c789406b1 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -447,7 +447,8 @@ static int break_ksm_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long nex if (is_migration_entry(entry)) page = pfn_swap_entry_to_page(entry); } - ret = page && PageKsm(page); + /* return 1 if the page is an normal ksm page or KSM-placed zero page */ + ret = (page && PageKsm(page)) || is_ksm_zero_pte(*pte); pte_unmap_unlock(pte, ptl); return ret; } @@ -1220,8 +1221,12 @@ static int replace_page(struct vm_area_struct *vma, struct page *page, page_add_anon_rmap(kpage, vma, addr, RMAP_NONE); newpte = mk_pte(kpage, vma->vm_page_prot); } else { - newpte = pte_mkspecial(pfn_pte(page_to_pfn(kpage), - vma->vm_page_prot)); + /* + * Use pte_mkdirty to mark the zero page mapped by KSM, and then + * we can easily track all KSM-placed zero pages by checking if + * the dirty bit in zero page's PTE is set. + */ + newpte = pte_mkdirty(pte_mkspecial(pfn_pte(page_to_pfn(kpage), vma->vm_page_prot))); /* * We're replacing an anonymous page with a zero page, which is * not anonymous. We need to do proper accounting otherwise we From patchwork Tue Jun 13 03:09:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Yang X-Patchwork-Id: 107050 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:994d:0:b0:3d9:f83d:47d9 with SMTP id k13csp274349vqr; Mon, 12 Jun 2023 20:15:51 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ4xrdg3Hei+g+c7SFVAfUVhnVCkpK/Wftj0gZruHPc+IG1dKi0/DQ4IA3qcGUGVacqVSk0g X-Received: by 2002:a17:907:a46:b0:977:e916:9b83 with SMTP id be6-20020a1709070a4600b00977e9169b83mr11864170ejc.8.1686626150837; Mon, 12 Jun 2023 20:15:50 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1686626150; cv=none; d=google.com; s=arc-20160816; b=DcImPfcXjLgPmLc9LaRR3skOA99fekP4D7ZTY9BIiwEFHhjtp9mo2hBqhIouAOKJLE hVM0r17hDSF5skj/rU6oKrxcGPzykP2F91SuvPCmYMPry2GVkyNH61ONq97LHslit2LZ G3BiycclWgHNw6FasGXnjcbMuqH+pltu8y8ksNJdrMZY9L+6Xl9rfaRwFm1UOzmqQzWb hmETitvFZNzEwK9R7cLIrnYI/90/vEleve6DMFtNe6v94wmRb192c2lJDhhuz3T5XVeX LLwwql4mBjlqxmPSNfOhAJcWujgY9VwDA8bIyQubeHKI0T/mdYZR6pUC06nfrq2dLGb6 UhZQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=Atw9I39Pna+3nig+tlnmh7Q52vrZOVT+0SdXjY3Bs3Y=; b=BzXKmwL7+F8xj907bgX4jVCTVp5vyn4sIkV6X6vhQSR/tBvl0PtP/kFuagEsOmKmt0 2TCf204rJ+X3u6m60BOqmBwM5mZt1jUEtrjWnnNR8Pnp+ALvXDQN2OMu8p0LI3O9J8VS fqK1gZ6Z4ZqPmLqU4WQYLXxx9LrYk/6jN7MO2nj+O7YH58rLzRSH8QsRta4ihnGu6K8Y qw8O5PO1647+K6Wtzgv+rew9MDUDVITXPrhBYxx76bSZY9SLtqcAec3ANqc2IIGYgAOE ZklmUidtTE3Gll3mEEptcmHqRdV8fCDh9YvvtPW4YQF1R96Xyn1FiuSN2Yv+Fb4Z17Vu cXzg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=zte.com.cn Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id v24-20020a17090690d800b00977878c3965si5913093ejw.824.2023.06.12.20.15.27; Mon, 12 Jun 2023 20:15:50 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=zte.com.cn Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239556AbjFMDLq (ORCPT + 99 others); Mon, 12 Jun 2023 23:11:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56162 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240433AbjFMDLG (ORCPT ); Mon, 12 Jun 2023 23:11:06 -0400 Received: from ubuntu20 (unknown [193.203.214.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F9CA119 for ; Mon, 12 Jun 2023 20:09:37 -0700 (PDT) Received: by ubuntu20 (Postfix, from userid 1003) id C5D63E22C2; Tue, 13 Jun 2023 11:09:35 +0800 (CST) From: Yang Yang To: akpm@linux-foundation.org, david@redhat.com Cc: yang.yang29@zte.com.cn, imbrenda@linux.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ran.xiaokai@zte.com.cn, xu.xin.sc@gmail.com, xu.xin16@zte.com.cn, Xuexin Jiang Subject: [PATCH RESEND v10 2/5] ksm: count all zero pages placed by KSM Date: Tue, 13 Jun 2023 11:09:34 +0800 Message-Id: <20230613030934.185944-1-yang.yang29@zte.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: <202306131104554703428@zte.com.cn> References: <202306131104554703428@zte.com.cn> MIME-Version: 1.0 X-Spam-Status: No, score=3.4 required=5.0 tests=BAYES_00, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,FSL_HELO_NON_FQDN_1, HEADER_FROM_DIFFERENT_DOMAINS,HELO_NO_DOMAIN,NO_DNS_FOR_FROM, RCVD_IN_PBL,RDNS_NONE,SPF_SOFTFAIL,SPOOFED_FREEMAIL_NO_RDNS, T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Level: *** X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1768555702705736830?= X-GMAIL-MSGID: =?utf-8?q?1768555702705736830?= From: xu xin As pages_sharing and pages_shared don't include the number of zero pages merged by KSM, we cannot know how many pages are zero pages placed by KSM when enabling use_zero_pages, which leads to KSM not being transparent with all actual merged pages by KSM. In the early days of use_zero_pages, zero-pages was unable to get unshared by the ways like MADV_UNMERGEABLE so it's hard to count how many times one of those zeropages was then unmerged. But now, unsharing KSM-placed zero page accurately has been achieved, so we can easily count both how many times a page full of zeroes was merged with zero-page and how many times one of those pages was then unmerged. and so, it helps to estimate memory demands when each and every shared page could get unshared. So we add ksm_zero_pages under /sys/kernel/mm/ksm/ to show the number of all zero pages placed by KSM. Meanwhile, we update the Documentation. Signed-off-by: xu xin Acked-by: David Hildenbrand Cc: Claudio Imbrenda Cc: Xuexin Jiang Reviewed-by: Xiaokai Ran Reviewed-by: Yang Yang --- Documentation/admin-guide/mm/ksm.rst | 7 +++++++ include/linux/ksm.h | 12 ++++++++++++ mm/khugepaged.c | 2 ++ mm/ksm.c | 12 ++++++++++++ mm/memory.c | 5 ++++- 5 files changed, 37 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst index 7626392fe82c..6cc919dbfd55 100644 --- a/Documentation/admin-guide/mm/ksm.rst +++ b/Documentation/admin-guide/mm/ksm.rst @@ -173,6 +173,13 @@ stable_node_chains the number of KSM pages that hit the ``max_page_sharing`` limit stable_node_dups number of duplicated KSM pages +ksm_zero_pages + how many zero pages that are still mapped into processes were mapped by + KSM when deduplicating. + +When ``use_zero_pages`` is/was enabled, the sum of ``pages_sharing`` + +``ksm_zero_pages`` represents the actual number of pages saved by KSM. +if ``use_zero_pages`` has never been enabled, ``ksm_zero_pages`` is 0. A high ratio of ``pages_sharing`` to ``pages_shared`` indicates good sharing, but a high ratio of ``pages_unshared`` to ``pages_sharing`` diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 98878107244f..e80aa49009b2 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -33,6 +33,14 @@ void __ksm_exit(struct mm_struct *mm); */ #define is_ksm_zero_pte(pte) (is_zero_pfn(pte_pfn(pte)) && pte_dirty(pte)) +extern unsigned long ksm_zero_pages; + +static inline void ksm_might_unmap_zero_page(pte_t pte) +{ + if (is_ksm_zero_pte(pte)) + ksm_zero_pages--; +} + static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) { int ret; @@ -101,6 +109,10 @@ static inline void ksm_exit(struct mm_struct *mm) { } +static inline void ksm_might_unmap_zero_page(pte_t pte) +{ +} + #ifdef CONFIG_MEMORY_FAILURE static inline void collect_procs_ksm(struct page *page, struct list_head *to_kill, int force_early) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 6b9d39d65b73..3f293e2436f3 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include @@ -711,6 +712,7 @@ static void __collapse_huge_page_copy_succeeded(pte_t *pte, spin_lock(ptl); ptep_clear(vma->vm_mm, address, _pte); spin_unlock(ptl); + ksm_might_unmap_zero_page(pteval); } } else { src_page = pte_page(pteval); diff --git a/mm/ksm.c b/mm/ksm.c index f31c789406b1..d3ed90159322 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -278,6 +278,9 @@ static unsigned int zero_checksum __read_mostly; /* Whether to merge empty (zeroed) pages with actual zero pages */ static bool ksm_use_zero_pages __read_mostly; +/* The number of zero pages which is placed by KSM */ +unsigned long ksm_zero_pages; + #ifdef CONFIG_NUMA /* Zeroed when merging across nodes is not allowed */ static unsigned int ksm_merge_across_nodes = 1; @@ -1227,6 +1230,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page, * the dirty bit in zero page's PTE is set. */ newpte = pte_mkdirty(pte_mkspecial(pfn_pte(page_to_pfn(kpage), vma->vm_page_prot))); + ksm_zero_pages++; /* * We're replacing an anonymous page with a zero page, which is * not anonymous. We need to do proper accounting otherwise we @@ -3354,6 +3358,13 @@ static ssize_t pages_volatile_show(struct kobject *kobj, } KSM_ATTR_RO(pages_volatile); +static ssize_t ksm_zero_pages_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%ld\n", ksm_zero_pages); +} +KSM_ATTR_RO(ksm_zero_pages); + static ssize_t general_profit_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { @@ -3421,6 +3432,7 @@ static struct attribute *ksm_attrs[] = { &pages_sharing_attr.attr, &pages_unshared_attr.attr, &pages_volatile_attr.attr, + &ksm_zero_pages_attr.attr, &full_scans_attr.attr, #ifdef CONFIG_NUMA &merge_across_nodes_attr.attr, diff --git a/mm/memory.c b/mm/memory.c index 8358f3b853f2..15e6bd757eab 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1415,8 +1415,10 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, tlb_remove_tlb_entry(tlb, pte, addr); zap_install_uffd_wp_if_needed(vma, addr, pte, details, ptent); - if (unlikely(!page)) + if (unlikely(!page)) { + ksm_might_unmap_zero_page(ptent); continue; + } delay_rmap = 0; if (!PageAnon(page)) { @@ -3120,6 +3122,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) inc_mm_counter(mm, MM_ANONPAGES); } } else { + ksm_might_unmap_zero_page(vmf->orig_pte); inc_mm_counter(mm, MM_ANONPAGES); } flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); From patchwork Tue Jun 13 03:09:38 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Yang X-Patchwork-Id: 107051 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:994d:0:b0:3d9:f83d:47d9 with SMTP id k13csp274400vqr; Mon, 12 Jun 2023 20:15:59 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ7w0st+HvKnzNb6IYEGyYRcMaw+1OlyuTRhE8GO/LQyNFsiidv9aiL6XkzUaILgdhxV4lF0 X-Received: by 2002:aa7:c047:0:b0:516:7840:3cb6 with SMTP id k7-20020aa7c047000000b0051678403cb6mr5165203edo.6.1686626159480; Mon, 12 Jun 2023 20:15:59 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1686626159; cv=none; d=google.com; s=arc-20160816; b=a8pu1oUh7i5tS9aUYq2AdgDF1YdtnFin7pdNSvhJJzggSmwNTUlGsvhFzR/hpdegv3 l8fgpQZj3t6jDaTmhGO02Zz2HAckq0ZyZZeQ75JnWwMr0Q/X9R0JW4N4Qt8FKRP4ESMC C6qBBJUhAPmjwtPQORFmuQt9O3ANhu8UVYhq50QTJi3wRwP0IlbA+wzqzDy6C35OlSig zUXK9yfrLRJdVMQ1B6DGUgMi9y9eczF5vDdw4mpwkp4tk1WttBOevi1tw2wjtrdQG/br SVO2ELlAJY9NuGH0ugNQl0JtiOl4UDtvHV0hGRdyHK//EZQ2or+vTYiYYYrVnbp8reEn zcyQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=T4tUn5j2c68i9rILRQlrVA2z90uKlIZVthgrc2Prd7I=; b=rHvIjsSbFIu+irhiFE6QvxGqhHA9vy/oNIU18h0QbWFRuQIDp4alGeSKEAfuu8l9jV mk1xNivkN0FtMjDUqT3+ixZ2pen259hHWuoirMTJmPRIwMny/5ck5Jtanfxsy1CmG9eD zLhQwoFun0b82eqOsdLZ6j4qrusyVem8u+Vqrzwt7teTXfR+uNIfYXHSzRK9F6fZJtoy Dc/2daTzz+++3+ZvomnQnVoJa/aAL+J7ydIekkmEBDfehyfae/7gP3+9n3RuaJKtVhA/ 8usPoyquBDb7KfZtRNcYfHautMQy+G+LU8Cdbyt6QdVTpY53ud+PSrXbZs4XauuR6Xoy oi5Q== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=zte.com.cn Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id bc19-20020a056402205300b0050bc49d4aeasi6761099edb.504.2023.06.12.20.15.35; Mon, 12 Jun 2023 20:15:59 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=zte.com.cn Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239569AbjFMDLu (ORCPT + 99 others); Mon, 12 Jun 2023 23:11:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56180 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240437AbjFMDLH (ORCPT ); Mon, 12 Jun 2023 23:11:07 -0400 Received: from ubuntu20 (unknown [193.203.214.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E599189 for ; Mon, 12 Jun 2023 20:09:41 -0700 (PDT) Received: by ubuntu20 (Postfix, from userid 1003) id CF36DE22C9; Tue, 13 Jun 2023 11:09:39 +0800 (CST) From: Yang Yang To: akpm@linux-foundation.org, david@redhat.com Cc: yang.yang29@zte.com.cn, imbrenda@linux.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ran.xiaokai@zte.com.cn, xu.xin.sc@gmail.com, xu.xin16@zte.com.cn, Xuexin Jiang Subject: [PATCH RESEND v10 3/5] ksm: add ksm zero pages for each process Date: Tue, 13 Jun 2023 11:09:38 +0800 Message-Id: <20230613030938.185993-1-yang.yang29@zte.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: <202306131104554703428@zte.com.cn> References: <202306131104554703428@zte.com.cn> MIME-Version: 1.0 X-Spam-Status: No, score=3.4 required=5.0 tests=BAYES_00, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,FSL_HELO_NON_FQDN_1, HEADER_FROM_DIFFERENT_DOMAINS,HELO_NO_DOMAIN,NO_DNS_FOR_FROM, RCVD_IN_PBL,RDNS_NONE,SPF_SOFTFAIL,SPOOFED_FREEMAIL_NO_RDNS, T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Level: *** X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1768555711626431108?= X-GMAIL-MSGID: =?utf-8?q?1768555711626431108?= From: xu xin As the number of ksm zero pages is not included in ksm_merging_pages per process when enabling use_zero_pages, it's unclear of how many actual pages are merged by KSM. To let users accurately estimate their memory demands when unsharing KSM zero-pages, it's necessary to show KSM zero- pages per process. In addition, it help users to know the actual KSM profit because KSM-placed zero pages are also benefit from KSM. since unsharing zero pages placed by KSM accurately is achieved, then tracking empty pages merging and unmerging is not a difficult thing any longer. Since we already have /proc//ksm_stat, just add the information of 'ksm_zero_pages' in it. Signed-off-by: xu xin Acked: David Hildenbrand Reviewed-by: Xiaokai Ran Reviewed-by: Yang Yang Cc: Claudio Imbrenda Cc: Xuexin Jiang --- fs/proc/base.c | 1 + include/linux/ksm.h | 8 +++++--- include/linux/mm_types.h | 9 +++++++-- mm/khugepaged.c | 2 +- mm/ksm.c | 1 + mm/memory.c | 4 ++-- 6 files changed, 17 insertions(+), 8 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 05452c3b9872..eb2e498e3b8d 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3207,6 +3207,7 @@ static int proc_pid_ksm_stat(struct seq_file *m, struct pid_namespace *ns, mm = get_task_mm(task); if (mm) { seq_printf(m, "ksm_rmap_items %lu\n", mm->ksm_rmap_items); + seq_printf(m, "ksm_zero_pages %lu\n", mm->ksm_zero_pages); seq_printf(m, "ksm_merging_pages %lu\n", mm->ksm_merging_pages); seq_printf(m, "ksm_process_profit %ld\n", ksm_process_profit(mm)); mmput(mm); diff --git a/include/linux/ksm.h b/include/linux/ksm.h index e80aa49009b2..c2dd786a30e1 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -35,10 +35,12 @@ void __ksm_exit(struct mm_struct *mm); extern unsigned long ksm_zero_pages; -static inline void ksm_might_unmap_zero_page(pte_t pte) +static inline void ksm_might_unmap_zero_page(struct mm_struct *mm, pte_t pte) { - if (is_ksm_zero_pte(pte)) + if (is_ksm_zero_pte(pte)) { ksm_zero_pages--; + mm->ksm_zero_pages--; + } } static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) @@ -109,7 +111,7 @@ static inline void ksm_exit(struct mm_struct *mm) { } -static inline void ksm_might_unmap_zero_page(pte_t pte) +static inline void ksm_might_unmap_zero_page(struct mm_struct *mm, pte_t pte) { } diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 306a3d1a0fa6..14f781509812 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -777,7 +777,7 @@ struct mm_struct { #ifdef CONFIG_KSM /* * Represent how many pages of this process are involved in KSM - * merging. + * merging (not including ksm_zero_pages). */ unsigned long ksm_merging_pages; /* @@ -785,7 +785,12 @@ struct mm_struct { * including merged and not merged. */ unsigned long ksm_rmap_items; -#endif + /* + * Represent how many empty pages are merged with kernel zero + * pages when enabling KSM use_zero_pages. + */ + unsigned long ksm_zero_pages; +#endif /* CONFIG_KSM */ #ifdef CONFIG_LRU_GEN struct { /* this mm_struct is on lru_gen_mm_list */ diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 3f293e2436f3..225d98744d2e 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -712,7 +712,7 @@ static void __collapse_huge_page_copy_succeeded(pte_t *pte, spin_lock(ptl); ptep_clear(vma->vm_mm, address, _pte); spin_unlock(ptl); - ksm_might_unmap_zero_page(pteval); + ksm_might_unmap_zero_page(vma->vm_mm, pteval); } } else { src_page = pte_page(pteval); diff --git a/mm/ksm.c b/mm/ksm.c index d3ed90159322..07a6fe7d7c99 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1231,6 +1231,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page, */ newpte = pte_mkdirty(pte_mkspecial(pfn_pte(page_to_pfn(kpage), vma->vm_page_prot))); ksm_zero_pages++; + mm->ksm_zero_pages++; /* * We're replacing an anonymous page with a zero page, which is * not anonymous. We need to do proper accounting otherwise we diff --git a/mm/memory.c b/mm/memory.c index 15e6bd757eab..811a98fb403e 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1416,7 +1416,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, zap_install_uffd_wp_if_needed(vma, addr, pte, details, ptent); if (unlikely(!page)) { - ksm_might_unmap_zero_page(ptent); + ksm_might_unmap_zero_page(mm, ptent); continue; } @@ -3122,7 +3122,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) inc_mm_counter(mm, MM_ANONPAGES); } } else { - ksm_might_unmap_zero_page(vmf->orig_pte); + ksm_might_unmap_zero_page(mm, vmf->orig_pte); inc_mm_counter(mm, MM_ANONPAGES); } flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); From patchwork Tue Jun 13 03:09:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Yang X-Patchwork-Id: 107052 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:994d:0:b0:3d9:f83d:47d9 with SMTP id k13csp274421vqr; Mon, 12 Jun 2023 20:16:04 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ4D522mF22J4Lr7bUJYpxQrupyB1iZvxlBlv/dr5sgcEoWt9NK5uFZ/VcrRT/69sxm4asIp X-Received: by 2002:a05:6402:47:b0:50b:c56c:43d0 with SMTP id f7-20020a056402004700b0050bc56c43d0mr7203065edu.1.1686626164381; Mon, 12 Jun 2023 20:16:04 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1686626164; cv=none; d=google.com; s=arc-20160816; b=BE45NtGc1PP4726CfeoffbVnAK7NjJfPLS5zTV8NE7V9TKMxALnchJXtoGV3cauF3k HG4k/pm8zDsuQfdtIscJ82k9ZpWgA4tGLypNFcmui8/6YL1GA53+NTrtKdR2jkwOMsxA p1GqbdOZK+sbFrJb+KIIe37JVjdlzcwjv8yVFqdWn7O8swd2kYOe/mO4vAjLkYWzBmfI VX2QVhq9tPqkIN0S6orfYKjQ5NZW57VoUfafIop9hVMsXrKVqBxRNHGI3cZa6yF+fbRm RkJaNg0DLA3xgwh7OeaJtxygKPMkk+DEW1AWaJPAQPvVlo42VAayMBQlpDvW2xD3cWXt cgwQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=/IGz+EOJ6ZJOoVXa4iGXtocLRze/sO07dBQARymqz/w=; b=HFPEiBU/EgcFYuobJVrjPEgeG4IMAPJdI8BAMUXDspRLr7P+Ag0KbBuSQUxAHn0kl3 K9MZBJ0EJHyhY6A/W980wsB8a5hps6uXN55pk2kKTSrLVJ/olwfSlMW3VxF0e0DgkalQ Ccmm3npkZly6nPhh6mm81vQ7TgjeIVe1NHSB3gm4ZeeklqZAZ29qW/8GDiTa6oPKS09K GCotV48U2v1/P9iOq52AsXcb3mxPxdqV22p7xCQ+S9ijTdiCUEZWI2x89CkCdIznh1u4 MEyNOoCM02qRPaRVS4bnCP/5hjT9IuaBgvksMskG2IA9kQSwQUmrJHDkQmYaZ33QKPmK zXew== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=zte.com.cn Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id dy19-20020a05640231f300b0050bc94fe05csi6937650edb.117.2023.06.12.20.15.41; Mon, 12 Jun 2023 20:16:04 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=zte.com.cn Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231941AbjFMDLz (ORCPT + 99 others); Mon, 12 Jun 2023 23:11:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56214 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240443AbjFMDLJ (ORCPT ); Mon, 12 Jun 2023 23:11:09 -0400 Received: from ubuntu20 (unknown [193.203.214.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26AFEE7A for ; Mon, 12 Jun 2023 20:09:46 -0700 (PDT) Received: by ubuntu20 (Postfix, from userid 1003) id B01FFE22BE; Tue, 13 Jun 2023 11:09:44 +0800 (CST) From: Yang Yang To: akpm@linux-foundation.org, david@redhat.com Cc: yang.yang29@zte.com.cn, imbrenda@linux.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ran.xiaokai@zte.com.cn, xu.xin.sc@gmail.com, xu.xin16@zte.com.cn, Jiang Xuexin Subject: [PATCH RESEND v10 4/5] ksm: consider KSM-placed zeropages when calculating KSM profit Date: Tue, 13 Jun 2023 11:09:42 +0800 Message-Id: <20230613030942.186041-1-yang.yang29@zte.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: <202306131104554703428@zte.com.cn> References: <202306131104554703428@zte.com.cn> MIME-Version: 1.0 X-Spam-Status: No, score=3.4 required=5.0 tests=BAYES_00, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,FSL_HELO_NON_FQDN_1, HEADER_FROM_DIFFERENT_DOMAINS,HELO_NO_DOMAIN,NO_DNS_FOR_FROM, RCVD_IN_PBL,RDNS_NONE,SPF_SOFTFAIL,SPOOFED_FREEMAIL_NO_RDNS, T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Level: *** X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1768555716948269050?= X-GMAIL-MSGID: =?utf-8?q?1768555716948269050?= From: xu xin When use_zero_pages is enabled, the calculation of ksm profit is not correct because ksm zero pages is not counted in. So update the calculation of KSM profit including the documentation. Signed-off-by: xu xin Acked-by: David Hildenbrand Cc: Xiaokai Ran Cc: Yang Yang Cc: Jiang Xuexin Cc: Claudio Imbrenda --- Documentation/admin-guide/mm/ksm.rst | 18 +++++++++++------- mm/ksm.c | 4 ++-- 2 files changed, 13 insertions(+), 9 deletions(-) diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst index 6cc919dbfd55..5c5be7bd84b8 100644 --- a/Documentation/admin-guide/mm/ksm.rst +++ b/Documentation/admin-guide/mm/ksm.rst @@ -203,21 +203,25 @@ several times, which are unprofitable memory consumed. 1) How to determine whether KSM save memory or consume memory in system-wide range? Here is a simple approximate calculation for reference:: - general_profit =~ pages_sharing * sizeof(page) - (all_rmap_items) * + general_profit =~ ksm_saved_pages * sizeof(page) - (all_rmap_items) * sizeof(rmap_item); - where all_rmap_items can be easily obtained by summing ``pages_sharing``, - ``pages_shared``, ``pages_unshared`` and ``pages_volatile``. + where ksm_saved_pages equals to the sum of ``pages_sharing`` + + ``ksm_zero_pages`` of the system, and all_rmap_items can be easily + obtained by summing ``pages_sharing``, ``pages_shared``, ``pages_unshared`` + and ``pages_volatile``. 2) The KSM profit inner a single process can be similarly obtained by the following approximate calculation:: - process_profit =~ ksm_merging_pages * sizeof(page) - + process_profit =~ ksm_saved_pages * sizeof(page) - ksm_rmap_items * sizeof(rmap_item). - where ksm_merging_pages is shown under the directory ``/proc//``, - and ksm_rmap_items is shown in ``/proc//ksm_stat``. The process profit - is also shown in ``/proc//ksm_stat`` as ksm_process_profit. + where ksm_saved_pages equals to the sum of ``ksm_merging_pages`` and + ``ksm_zero_pages``, both of which are shown under the directory + ``/proc//ksm_stat``, and ksm_rmap_items is also shown in + ``/proc//ksm_stat``. The process profit is also shown in + ``/proc//ksm_stat`` as ksm_process_profit. From the perspective of application, a high ratio of ``ksm_rmap_items`` to ``ksm_merging_pages`` means a bad madvise-applied policy, so developers or diff --git a/mm/ksm.c b/mm/ksm.c index 07a6fe7d7c99..1c7d0e215c47 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -3090,7 +3090,7 @@ static void wait_while_offlining(void) #ifdef CONFIG_PROC_FS long ksm_process_profit(struct mm_struct *mm) { - return mm->ksm_merging_pages * PAGE_SIZE - + return (long)(mm->ksm_merging_pages + mm->ksm_zero_pages) * PAGE_SIZE - mm->ksm_rmap_items * sizeof(struct ksm_rmap_item); } #endif /* CONFIG_PROC_FS */ @@ -3371,7 +3371,7 @@ static ssize_t general_profit_show(struct kobject *kobj, { long general_profit; - general_profit = ksm_pages_sharing * PAGE_SIZE - + general_profit = (ksm_pages_sharing + ksm_zero_pages) * PAGE_SIZE - ksm_rmap_items * sizeof(struct ksm_rmap_item); return sysfs_emit(buf, "%ld\n", general_profit); From patchwork Tue Jun 13 03:09:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Yang X-Patchwork-Id: 107057 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:994d:0:b0:3d9:f83d:47d9 with SMTP id k13csp279018vqr; Mon, 12 Jun 2023 20:31:13 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ5E7Rnw7kJclzuH0KizYDJrQFAOj9/x1GOx1WxRm9AIqxkltP70O2OyZ+M1fLIZHkA6SIdW X-Received: by 2002:a05:6830:1144:b0:6b2:91a7:7e21 with SMTP id x4-20020a056830114400b006b291a77e21mr8198081otq.4.1686627073108; Mon, 12 Jun 2023 20:31:13 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1686627073; cv=none; d=google.com; s=arc-20160816; b=BI9hYuRMwxyDKLfD4J9LE+F6yqfx0q+XT9HRL3BttuprV3aHLdy4uaY8krH0gqRGjK M0LdxbndmjpdcpKbO2dvHASWdlkYdvwFRKbuCgHho3bgDjOQ+v7cnOZsLDs+5TjJsYn/ JEs2qhra5OOxJs0Hg/7eEIH7QKMafXpyMLHsoUZTjB8nmZMau0xwq/lQ0LY5d8NagiDw RrevEmFxsNp36GATHMkvND8xy9BdFiZCePTZKI0c4plm5zMmhxxYyX8gSIfE8z5Js5R7 jvPdrS8Hz2Od5jtJn6yPI2jyUPxSTZ//F842R2S84ti3bA0ipFbkPlqK5K2u+mqk0kPw zsrw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=yH2Rwrj/53jUsvmvGOt2taD8ct0HYIFza7gED674V0U=; b=i/sfhtdNBy82pSiGvoFuKvmQYe4cxMajqHVbaluO/E/Nq8I2cglrIJIvurN+iosq// AovlMiL9RXKYL62Ojmsl3Ol/7fw8qV/zB1keULTe3LLRPOxQkBvlNB8ZY3KGLHA5sysO f+O4wzm6FxiZw4D8048EqvgADxH5bno53NaQwsHCSbV+10iFYONlOHNoTbUcbSemswKa 2S0gg+BUmMp8GDyGBNtjUh7WWMTDx3MVmdZLFPMlQMqf81jAw4zfW5uvSF67hBK9Jk/3 uEuJj7Is50S0lSpHLjlnk4bsuiq9X+KfUqAsT+/e+pl4cl13Taqe6x+QDdYXKoWqSZU0 na/A== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=zte.com.cn Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id p17-20020a639511000000b005369f4111aesi7446878pgd.849.2023.06.12.20.30.59; Mon, 12 Jun 2023 20:31:13 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=zte.com.cn Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239609AbjFMDMA (ORCPT + 99 others); Mon, 12 Jun 2023 23:12:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240450AbjFMDLL (ORCPT ); Mon, 12 Jun 2023 23:11:11 -0400 Received: from ubuntu20 (unknown [193.203.214.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 51E47172A for ; Mon, 12 Jun 2023 20:09:50 -0700 (PDT) Received: by ubuntu20 (Postfix, from userid 1003) id D996AE22D8; Tue, 13 Jun 2023 11:09:48 +0800 (CST) From: Yang Yang To: akpm@linux-foundation.org, david@redhat.com Cc: yang.yang29@zte.com.cn, imbrenda@linux.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ran.xiaokai@zte.com.cn, xu.xin.sc@gmail.com, xu.xin16@zte.com.cn, Xuexin Jiang Subject: [PATCH RESEND v10 5/5] selftest: add a testcase of ksm zero pages Date: Tue, 13 Jun 2023 11:09:47 +0800 Message-Id: <20230613030947.186089-1-yang.yang29@zte.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: <202306131104554703428@zte.com.cn> References: <202306131104554703428@zte.com.cn> MIME-Version: 1.0 X-Spam-Status: No, score=3.4 required=5.0 tests=BAYES_00, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,FSL_HELO_NON_FQDN_1, HEADER_FROM_DIFFERENT_DOMAINS,HELO_NO_DOMAIN,NO_DNS_FOR_FROM, RCVD_IN_PBL,RDNS_NONE,SPF_SOFTFAIL,SPOOFED_FREEMAIL_NO_RDNS, T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Level: *** X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1768556670043263224?= X-GMAIL-MSGID: =?utf-8?q?1768556670043263224?= From: xu xin Add a function test_unmerge_zero_page() to test the functionality on unsharing and counting ksm-placed zero pages and counting of this patch series. test_unmerge_zero_page() actually contains four subjct test objects: (1) whether the count of ksm zero pages can update correctly after merging; (2) whether the count of ksm zero pages can update correctly after unmerging by madvise(...MADV_UNMERGEABLE); (3) whether the count of ksm zero pages can update correctly after unmerging by triggering write fault. (4) whether ksm zero pages are really unmerged. Signed-off-by: xu xin Acked-by: David Hildenbrand Reviewed-by: Xiaokai Ran Reviewed-by: Yang Yang Cc: Claudio Imbrenda Cc: Xuexin Jiang --- tools/testing/selftests/mm/ksm_functional_tests.c | 98 ++++++++++++++++++++++- 1 file changed, 97 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c index 26853badae70..0de9d33cd565 100644 --- a/tools/testing/selftests/mm/ksm_functional_tests.c +++ b/tools/testing/selftests/mm/ksm_functional_tests.c @@ -29,6 +29,8 @@ static int ksm_fd; static int ksm_full_scans_fd; +static int proc_self_ksm_stat_fd; +static int ksm_use_zero_pages_fd; static int pagemap_fd; static size_t pagesize; @@ -59,6 +61,33 @@ static bool range_maps_duplicates(char *addr, unsigned long size) return false; } +static long get_my_ksm_zero_pages(void) +{ + char buf[200]; + char *substr_ksm_zero; + size_t value_pos; + ssize_t read_size; + unsigned long my_ksm_zero_pages; + + if (!proc_self_ksm_stat_fd) + return 0; + + read_size = pread(proc_self_ksm_stat_fd, buf, sizeof(buf) - 1, 0); + if (read_size < 0) + return -errno; + + buf[read_size] = 0; + + substr_ksm_zero = strstr(buf, "ksm_zero_pages"); + if (!substr_ksm_zero) + return 0; + + value_pos = strcspn(substr_ksm_zero, "0123456789"); + my_ksm_zero_pages = strtol(substr_ksm_zero + value_pos, NULL, 10); + + return my_ksm_zero_pages; +} + static long ksm_get_full_scans(void) { char buf[10]; @@ -159,6 +188,70 @@ static void test_unmerge(void) munmap(map, size); } +static void test_unmerge_zero_pages(void) +{ + const unsigned int size = 2 * MiB; + char *map; + unsigned int offs; + unsigned long pages_expected; + + ksft_print_msg("[RUN] %s\n", __func__); + + if (proc_self_ksm_stat_fd < 0) { + ksft_test_result_skip("open(\"/proc/self/ksm_stat\") failed\n"); + return; + } + if (ksm_use_zero_pages_fd < 0) { + ksft_test_result_skip("open \"/sys/kernel/mm/ksm/use_zero_pages\" failed\n"); + return; + } + if (write(ksm_use_zero_pages_fd, "1", 1) != 1) { + ksft_test_result_skip("write \"/sys/kernel/mm/ksm/use_zero_pages\" failed\n"); + return; + } + + /* Let KSM deduplicate zero pages. */ + map = mmap_and_merge_range(0x00, size, false); + if (map == MAP_FAILED) + return; + + /* Check if ksm_zero_pages is updated correctly after KSM merging */ + pages_expected = size / pagesize; + if (pages_expected != get_my_ksm_zero_pages()) { + ksft_test_result_fail("'ksm_zero_pages' updated after merging\n"); + goto unmap; + } + + /* Try to unmerge half of the region */ + if (madvise(map, size / 2, MADV_UNMERGEABLE)) { + ksft_test_result_fail("MADV_UNMERGEABLE failed\n"); + goto unmap; + } + + /* Check if ksm_zero_pages is updated correctly after unmerging */ + pages_expected /= 2; + if (pages_expected != get_my_ksm_zero_pages()) { + ksft_test_result_fail("'ksm_zero_pages' updated after unmerging\n"); + goto unmap; + } + + /* Trigger unmerging of the other half by writing to the pages. */ + for (offs = size / 2; offs < size; offs += pagesize) + *((unsigned int *)&map[offs]) = offs; + + /* Now we should have no zeropages remaining. */ + if (get_my_ksm_zero_pages()) { + ksft_test_result_fail("'ksm_zero_pages' updated after write fault\n"); + goto unmap; + } + + /* Check if ksm zero pages are really unmerged */ + ksft_test_result(!range_maps_duplicates(map, size), + "KSM zero pages were unmerged\n"); +unmap: + munmap(map, size); +} + static void test_unmerge_discarded(void) { const unsigned int size = 2 * MiB; @@ -358,7 +451,7 @@ static void test_prctl_unmerge(void) int main(int argc, char **argv) { - unsigned int tests = 5; + unsigned int tests = 6; int err; #ifdef __NR_userfaultfd @@ -379,8 +472,11 @@ int main(int argc, char **argv) pagemap_fd = open("/proc/self/pagemap", O_RDONLY); if (pagemap_fd < 0) ksft_exit_skip("open(\"/proc/self/pagemap\") failed\n"); + proc_self_ksm_stat_fd = open("/proc/self/ksm_stat", O_RDONLY); + ksm_use_zero_pages_fd = open("/sys/kernel/mm/ksm/use_zero_pages", O_RDWR); test_unmerge(); + test_unmerge_zero_pages(); test_unmerge_discarded(); #ifdef __NR_userfaultfd test_unmerge_uffd_wp();