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 46A38CD13D2 for ; Mon, 18 Sep 2023 19:38:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229379AbjIRTiz (ORCPT ); Mon, 18 Sep 2023 15:38:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229477AbjIRTiy (ORCPT ); Mon, 18 Sep 2023 15:38:54 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 928DF10A for ; Mon, 18 Sep 2023 12:38:49 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D1F1C433CA; Mon, 18 Sep 2023 19:38:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1695065929; bh=mYNDs8B43LPEqO4dHDvf0TlKvPG7O26Tpz3knZQJTq4=; h=Date:To:From:Subject:From; b=SulttOfhbyp77Ostsz2neUknEc0tNFGQWgrf5rpN0xKAbHtni17tOEoO6+JXVdQ9w hV7RIgiLKpz+pAD9wXrhNtaByGGUseYDJ57DnRN6JX0Io/8amX8AuocbosqzK7bvfd UpQ/i/2WSaVfwHdcw1QYjY/sP4lLor1C5Szepe0E= Date: Mon, 18 Sep 2023 12:38:48 -0700 To: mm-commits@vger.kernel.org, riel@surriel.com, hughd@google.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: <20230918193849.1D1F1C433CA@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, 18 Sep 2023 11:58:15 -0700 This adds documentation for the smart scan mode of KSM. Link: https://lkml.kernel.org/r/20230918185816.1518366-4-shr@devkernel.io Signed-off-by: Stefan Roesch Reviewed-by: David Hildenbrand Cc: Hugh Dickins 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-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