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 4F5E5C433F5 for ; Fri, 25 Mar 2022 01:35:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357568AbiCYBg5 (ORCPT ); Thu, 24 Mar 2022 21:36:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40632 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357473AbiCYBew (ORCPT ); Thu, 24 Mar 2022 21:34:52 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38E14C12EC for ; Thu, 24 Mar 2022 18:32:53 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id CB43360909 for ; Fri, 25 Mar 2022 01:32:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F3E6C340ED; Fri, 25 Mar 2022 01:32:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1648171972; bh=6KRiwKBdqXzgD65rt0nw4rchcfPRfH73/fSiaQW5Vj8=; h=Date:To:From:Subject:From; b=0jyCb85rTGC/k51AXo90k0O+zboairnggVthCDpVQYPBH5DYQykdI0IKMMvqQAwrl JiKnsAULuUm+8UETji4cibOHtC0MaVqcN6buHszmUewgnRBFBq7gpy0RoPyjQrkSdl moiQkDfO1aAjQVlG1D88ReS57DRSBbedG/hYA4Q0= Date: Thu, 24 Mar 2022 18:32:51 -0700 To: mm-commits@vger.kernel.org, vitaly.wool@konsulko.com, sjenning@redhat.com, ddstreet@ieee.org, maciej.szmigiero@oracle.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged] mm-zswapc-allow-handling-just-same-value-filled-pages.patch removed from -mm tree Message-Id: <20220325013252.2F3E6C340ED@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/zswap.c: allow handling just same-value filled pages has been removed from the -mm tree. Its filename was mm-zswapc-allow-handling-just-same-value-filled-pages.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: "Maciej S. Szmigiero" Subject: mm/zswap.c: allow handling just same-value filled pages Zswap has an ability to efficiently store same-value filled pages, which can be turned on and off using the "same_filled_pages_enabled" parameter. However, there is currently no way to enable just this (lightweight) functionality, while not making use of the whole compressed page storage machinery. Add a "non_same_filled_pages_enabled" parameter which allows disabling handling of pages that aren't same-value filled. This way zswap can be run in such lightweight same-value filled pages only mode. Link: https://lkml.kernel.org/r/7dbafa963e8bab43608189abbe2067f4b9287831.1641247624.git.maciej.szmigiero@oracle.com Signed-off-by: Maciej S. Szmigiero Cc: Seth Jennings Cc: Dan Streetman Cc: Vitaly Wool Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/zswap.rst | 22 +++++++++++++++++++--- mm/zswap.c | 15 ++++++++++++++- 2 files changed, 33 insertions(+), 4 deletions(-) --- a/Documentation/admin-guide/mm/zswap.rst~mm-zswapc-allow-handling-just-same-value-filled-pages +++ a/Documentation/admin-guide/mm/zswap.rst @@ -130,9 +130,25 @@ attribute, e.g.:: echo 1 > /sys/module/zswap/parameters/same_filled_pages_enabled When zswap same-filled page identification is disabled at runtime, it will stop -checking for the same-value filled pages during store operation. However, the -existing pages which are marked as same-value filled pages remain stored -unchanged in zswap until they are either loaded or invalidated. +checking for the same-value filled pages during store operation. +In other words, every page will be then considered non-same-value filled. +However, the existing pages which are marked as same-value filled pages remain +stored unchanged in zswap until they are either loaded or invalidated. + +In some circumstances it might be advantageous to make use of just the zswap +ability to efficiently store same-filled pages without enabling the whole +compressed page storage. +In this case the handling of non-same-value pages by zswap (enabled by default) +can be disabled by setting the ``non_same_filled_pages_enabled`` attribute +to 0, e.g. ``zswap.non_same_filled_pages_enabled=0``. +It can also be enabled and disabled at runtime using the sysfs +``non_same_filled_pages_enabled`` attribute, e.g.:: + + echo 1 > /sys/module/zswap/parameters/non_same_filled_pages_enabled + +Disabling both ``zswap.same_filled_pages_enabled`` and +``zswap.non_same_filled_pages_enabled`` effectively disables accepting any new +pages by zswap. To prevent zswap from shrinking pool when zswap is full and there's a high pressure on swap (this will result in flipping pages in and out zswap pool --- a/mm/zswap.c~mm-zswapc-allow-handling-just-same-value-filled-pages +++ a/mm/zswap.c @@ -120,11 +120,19 @@ static unsigned int zswap_accept_thr_per module_param_named(accept_threshold_percent, zswap_accept_thr_percent, uint, 0644); -/* Enable/disable handling same-value filled pages (enabled by default) */ +/* + * Enable/disable handling same-value filled pages (enabled by default). + * If disabled every page is considered non-same-value filled. + */ static bool zswap_same_filled_pages_enabled = true; module_param_named(same_filled_pages_enabled, zswap_same_filled_pages_enabled, bool, 0644); +/* Enable/disable handling non-same-value filled pages (enabled by default) */ +static bool zswap_non_same_filled_pages_enabled = true; +module_param_named(non_same_filled_pages_enabled, zswap_non_same_filled_pages_enabled, + bool, 0644); + /********************************* * data structures **********************************/ @@ -1147,6 +1155,11 @@ static int zswap_frontswap_store(unsigne kunmap_atomic(src); } + if (!zswap_non_same_filled_pages_enabled) { + ret = -EINVAL; + goto freepage; + } + /* if entry is successfully added, it keeps the reference */ entry->pool = zswap_pool_current_get(); if (!entry->pool) { _ Patches currently in -mm which might be from maciej.szmigiero@oracle.com are