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[2620:137:e000::1:20]) by mx.google.com with ESMTP id i1-20020a056402054100b005049ca83135si944319edx.511.2023.04.12.23.09.49; Wed, 12 Apr 2023 23:10:12 -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 S229739AbjDMFq4 (ORCPT + 99 others); Thu, 13 Apr 2023 01:46:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52102 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229482AbjDMFqz (ORCPT ); Thu, 13 Apr 2023 01:46:55 -0400 Received: from mxhk.zte.com.cn (mxhk.zte.com.cn [63.216.63.35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0DDBE40 for ; Wed, 12 Apr 2023 22:46:53 -0700 (PDT) Received: from mse-fl2.zte.com.cn (unknown [10.5.228.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mxhk.zte.com.cn (FangMail) with ESMTPS id 4PxpVg6Yncz4xVnK; Thu, 13 Apr 2023 13:46:51 +0800 (CST) Received: from szxlzmapp06.zte.com.cn ([10.5.230.252]) by mse-fl2.zte.com.cn with SMTP id 33D5klSF069087; Thu, 13 Apr 2023 13:46:47 +0800 (+08) (envelope-from yang.yang29@zte.com.cn) Received: from mapi (szxlzmapp01[null]) by mapi (Zmail) with MAPI id mid14; Thu, 13 Apr 2023 13:46:48 +0800 (CST) Date: Thu, 13 Apr 2023 13:46:48 +0800 (CST) X-Zmail-TransId: 2b0364379748ffffffffc3a-dc384 X-Mailer: Zmail v1.0 Message-ID: <202304131346489021903@zte.com.cn> Mime-Version: 1.0 From: To: , Cc: , , , , , , Subject: =?utf-8?q?=5BPATCH_v7_0/6=5D_ksm=3A_support_tracking_KSM-placed_zer?= =?utf-8?q?o-pages?= X-MAIL: mse-fl2.zte.com.cn 33D5klSF069087 X-Fangmail-Gw-Spam-Type: 0 X-Fangmail-Anti-Spam-Filtered: true X-Fangmail-MID-QID: 6437974B.000/4PxpVg6Yncz4xVnK X-Spam-Status: No, score=0.6 required=5.0 tests=BAYES_00,SORTED_RECIPS, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY autolearn=no autolearn_force=no version=3.4.6 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?1763040258115107477?= X-GMAIL-MSGID: =?utf-8?q?1763040258115107477?= From: xu xin The core idea of this patch set is to enable users to perceive the number of any pages merged by KSM, regardless of whether use_zero_page switch has been turned on, so that users can know how much free memory increase is really due to their madvise(MERGEABLE) actions. But the problem is, when enabling use_zero_pages, all empty pages will be merged with kernel zero pages instead of with each other as use_zero_pages is disabled, and then these zero-pages are no longer monitored by KSM. The motivations to do this is seen at: https://lore.kernel.org/lkml/202302100915227721315@zte.com.cn/ In one word, we hope to implement the support for KSM-placed zero pages tracking without affecting the feature of use_zero_pages, so that app developer can also benefit from knowing the actual KSM profit by getting KSM-placed zero pages to optimize applications eventually when /sys/kernel/mm/ksm/use_zero_pages is enabled. the patch uses pte_mkdirty (related with architecture) to mark KSM-placed zero pages. Some architecture(like sparc64) treat R/O dirty PTEs as writable, which will break KSM pages state (wrprotect) and affect the KSM functionality. For safety, we restrict this feature only to the tested and known-working architechtures (ARM, ARM64, and X86) fow now. Change log ---------- v6->v7: This is an all-newed version which is different from v6 which relys on KSM's rmap_item. The patch series don't rely on rmap_item but pte_dirty, so the general handling of tracking KSM-placed zero-pages is simplified a lot. For safety, we restrict this feature only to the tested and known-working architechtures (ARM, ARM64, and X86) fow now. xu xin (6): ksm: support unsharing KSM-placed zero pages ksm: count all zero pages placed by KSM ksm: add ksm zero pages for each process ksm: add documentation for ksm zero pages ksm: update the calculation of KSM profit selftest: add a testcase of ksm zero pages Documentation/admin-guide/mm/ksm.rst | 26 +++++--- fs/proc/base.c | 3 + include/linux/ksm.h | 27 ++++++++ include/linux/mm_types.h | 11 +++- mm/Kconfig | 23 ++++++- mm/ksm.c | 28 ++++++++- mm/memory.c | 7 ++- tools/testing/selftests/mm/ksm_functional_tests.c | 75 +++++++++++++++++++++++ 8 files changed, 187 insertions(+), 13 deletions(-)