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 A77D7C77B61 for ; Thu, 13 Apr 2023 05:58:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229784AbjDMF6F (ORCPT ); Thu, 13 Apr 2023 01:58:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56764 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229484AbjDMF6D (ORCPT ); Thu, 13 Apr 2023 01:58:03 -0400 Received: from ubuntu20 (unknown [193.203.214.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 42D86212C for ; Wed, 12 Apr 2023 22:58:02 -0700 (PDT) Received: by ubuntu20 (Postfix, from userid 1003) id E73CFE1A31; Thu, 13 Apr 2023 05:58:00 +0000 (UTC) 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 v7 5/6] ksm: update the calculation of KSM profit Date: Thu, 13 Apr 2023 13:57:59 +0800 Message-Id: <20230413055759.181210-1-yang.yang29@zte.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: <202304131346489021903@zte.com.cn> References: <202304131346489021903@zte.com.cn> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Cc: Xiaokai Ran Cc: Yang Yang Cc: Jiang Xuexin Cc: Claudio Imbrenda Cc: David Hildenbrand --- Documentation/admin-guide/mm/ksm.rst | 18 +++++++++++------- mm/ksm.c | 5 +++++ 2 files changed, 16 insertions(+), 7 deletions(-) diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst index 64e6a13bda74..1a0f623cd570 100644 --- a/Documentation/admin-guide/mm/ksm.rst +++ b/Documentation/admin-guide/mm/ksm.rst @@ -243,21 +243,25 @@ 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//``, and ksm_rmap_items is 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 7867fae3c61c..10902c8c503f 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2936,8 +2936,13 @@ static void wait_while_offlining(void) #ifdef CONFIG_PROC_FS long ksm_process_profit(struct mm_struct *mm) { +#ifdef CONFIG_KSM_ZERO_PAGES_TRACK + return (long)(mm->ksm_merging_pages + mm->ksm_zero_pages) * PAGE_SIZE - + mm->ksm_rmap_items * sizeof(struct ksm_rmap_item); +#else return (long)mm->ksm_merging_pages * PAGE_SIZE - mm->ksm_rmap_items * sizeof(struct ksm_rmap_item); +#endif } /* Return merge type name as string. */ -- 2.15.2