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 1C678E7F144 for ; Tue, 26 Sep 2023 23:29:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231822AbjIZX34 (ORCPT ); Tue, 26 Sep 2023 19:29:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229640AbjIZX14 (ORCPT ); Tue, 26 Sep 2023 19:27:56 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D5FD1F9CF for ; Tue, 26 Sep 2023 15:32:20 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 71A74C433BB; Tue, 26 Sep 2023 21:13:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1695762806; bh=tovF7n+4KvYSKMmY9b6SZV/3pyG2XpT6jEsd/pCDZ+A=; h=Date:To:From:Subject:From; b=H5DbgQ5BKW7yqeXBJs9ZZlkwnkaxSyAGgZDlOCfVd52ViELwGkYWmnaakJY9r+DzJ wFLLuckVUSQaCFK16dubLVkwpSzLxqq3M0wXpTnib47nQW0Oy7tbpfDaOSHo5++63L G2ZXsGdkI7vf4sza/0ZTSvFJc6DXETIEjMI9k/F8= Date: Tue, 26 Sep 2023 14:13:25 -0700 To: mm-commits@vger.kernel.org, riel@surriel.com, hannes@cmpxchg.org, david@redhat.com, shr@devkernel.io, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-ksm-document-smart-scan-mode.patch added to mm-unstable branch Message-Id: <20230926211326.71A74C433BB@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/ksm: document smart scan mode has been added to the -mm mm-unstable branch. Its filename is mm-ksm-document-smart-scan-mode.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-ksm-document-smart-scan-mode.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Stefan Roesch Subject: mm/ksm: document smart scan mode Date: Mon, 25 Sep 2023 21:09:38 -0700 This adds documentation for the smart scan mode of KSM. Link: https://lkml.kernel.org/r/20230926040939.516161-4-shr@devkernel.io Signed-off-by: Stefan Roesch Reviewed-by: David Hildenbrand Cc: Johannes Weiner Cc: Rik van Riel Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/ksm.rst | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/Documentation/admin-guide/mm/ksm.rst~mm-ksm-document-smart-scan-mode +++ a/Documentation/admin-guide/mm/ksm.rst @@ -155,6 +155,15 @@ stable_node_chains_prune_millisecs scan. It's a noop if not a single KSM page hit the ``max_page_sharing`` yet. +smart_scan + By default KSM checks every candidate page for each scan. It does + not take into account historic information. When smart scan is + enabled, pages that have previously not been de-duplicated get + skipped. How often these pages are skipped depends on how often + de-duplication has already been tried and failed. By default this + optimization is disabled. The ``pages_skipped`` metric shows how + effetive the setting is. + The effectiveness of KSM and MADV_MERGEABLE is shown in ``/sys/kernel/mm/ksm/``: general_profit _ Patches currently in -mm which might be from shr@devkernel.io are mm-ksm-support-fork-exec-for-prctl.patch mm-ksm-test-case-for-prctl-fork-exec-workflow.patch mm-ksm-add-smart-page-scanning-mode.patch mm-ksm-add-pages_skipped-metric.patch mm-ksm-document-smart-scan-mode.patch mm-ksm-document-pages_skipped-sysfs-knob.patch