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 130A5C63797 for ; Fri, 3 Feb 2023 06:40:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232228AbjBCGj7 (ORCPT ); Fri, 3 Feb 2023 01:39:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232254AbjBCGjE (ORCPT ); Fri, 3 Feb 2023 01:39:04 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C73F48E6AE for ; Thu, 2 Feb 2023 22:36:56 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id 6620EB82986 for ; Fri, 3 Feb 2023 06:36:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 03D7CC433EF; Fri, 3 Feb 2023 06:36:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1675406214; bh=YPvtnCdos+SvHyZOFCCPFilM2FWkXtWjcQ12YnhUMhw=; h=Date:To:From:Subject:From; b=BLKl6AD3L3jK4M+VYeowt755hPCL2GboNEE1R7jElk+e1vxufoAEGHa4t2V4dS32i GoyFGTYivvTTRT65iAheNZdvp0Y2yvdb0P5qNkGx/coXoBrRBkmO7MANT3MIVrX60h /b07dBS7V3pI42XK1XNV5/darz1lKXQnYjESSo3c= Date: Thu, 02 Feb 2023 22:36:53 -0800 To: mm-commits@vger.kernel.org, vbabka@suse.cz, rppt@kernel.org, rientjes@google.com, quic_charante@quicinc.com, mhocko@suse.com, lizhe.67@bytedance.com, david@redhat.com, pasha.tatashin@soleen.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-page_ext-do-not-allocate-space-for-page_ext-flags-if-not-needed.patch removed from -mm tree Message-Id: <20230203063654.03D7CC433EF@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: mm/page_ext: do not allocate space for page_ext->flags if not needed has been removed from the -mm tree. Its filename was mm-page_ext-do-not-allocate-space-for-page_ext-flags-if-not-needed.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Pasha Tatashin Subject: mm/page_ext: do not allocate space for page_ext->flags if not needed Date: Fri, 13 Jan 2023 15:42:53 +0000 There is 8 byte page_ext->flags field allocated per page whenever CONFIG_PAGE_EXTENSION is enabled. However, not every user of page_ext uses flags. Therefore, check whether flags is needed at least by one user and if so allocate space for it. For example when page_table_check is enabled, on a machine with 128G of memory before the fix: [ 2.244288] allocated 536870912 bytes of page_ext after the fix: [ 2.160154] allocated 268435456 bytes of page_ext Also, add a kernel-doc comment before page_ext_operations that describes the fields, and remove check if need() is set, as that is now a required field. [pasha.tatashin@soleen.com: address comments from Mike Rapoport] Link: https://lkml.kernel.org/r/20230117202103.1412449-1-pasha.tatashin@soleen.com Link: https://lkml.kernel.org/r/20230113154253.92480-1-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin Acked-by: David Hildenbrand Acked-by: Vlastimil Babka Acked-by: David Rientjes Reviewed-by: Mike Rapoport (IBM) Cc: Charan Teja Kalla Cc: Li Zhe Cc: Michal Hocko Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- --- a/include/linux/page_ext.h~mm-page_ext-do-not-allocate-space-for-page_ext-flags-if-not-needed +++ a/include/linux/page_ext.h @@ -7,15 +7,33 @@ #include struct pglist_data; + +/** + * struct page_ext_operations - per page_ext client operations + * @offset: Offset to the client's data within page_ext. Offset is returned to + * the client by page_ext_init. + * @size: The size of the client data within page_ext. + * @need: Function that returns true if client requires page_ext. + * @init: (optional) Called to initialize client once page_exts are allocated. + * @need_shared_flags: True when client is using shared page_ext->flags + * field. + * + * Each Page Extension client must define page_ext_operations in + * page_ext_ops array. + */ struct page_ext_operations { size_t offset; size_t size; bool (*need)(void); void (*init)(void); + bool need_shared_flags; }; #ifdef CONFIG_PAGE_EXTENSION +/* + * The page_ext_flags users must set need_shared_flags to true. + */ enum page_ext_flags { PAGE_EXT_OWNER, PAGE_EXT_OWNER_ALLOCATED, --- a/mm/page_ext.c~mm-page_ext-do-not-allocate-space-for-page_ext-flags-if-not-needed +++ a/mm/page_ext.c @@ -71,6 +71,7 @@ static bool need_page_idle(void) } static struct page_ext_operations page_idle_ops __initdata = { .need = need_page_idle, + .need_shared_flags = true, }; #endif @@ -86,7 +87,7 @@ static struct page_ext_operations *page_ #endif }; -unsigned long page_ext_size = sizeof(struct page_ext); +unsigned long page_ext_size; static unsigned long total_usage; static struct page_ext *lookup_page_ext(const struct page *page); @@ -106,7 +107,16 @@ static bool __init invoke_need_callbacks bool need = false; for (i = 0; i < entries; i++) { - if (page_ext_ops[i]->need && page_ext_ops[i]->need()) { + if (page_ext_ops[i]->need()) { + if (page_ext_ops[i]->need_shared_flags) { + page_ext_size = sizeof(struct page_ext); + break; + } + } + } + + for (i = 0; i < entries; i++) { + if (page_ext_ops[i]->need()) { page_ext_ops[i]->offset = page_ext_size; page_ext_size += page_ext_ops[i]->size; need = true; --- a/mm/page_owner.c~mm-page_ext-do-not-allocate-space-for-page_ext-flags-if-not-needed +++ a/mm/page_owner.c @@ -99,6 +99,7 @@ struct page_ext_operations page_owner_op .size = sizeof(struct page_owner), .need = need_page_owner, .init = init_page_owner, + .need_shared_flags = true, }; static inline struct page_owner *get_page_owner(struct page_ext *page_ext) --- a/mm/page_table_check.c~mm-page_ext-do-not-allocate-space-for-page_ext-flags-if-not-needed +++ a/mm/page_table_check.c @@ -45,6 +45,7 @@ struct page_ext_operations page_table_ch .size = sizeof(struct page_table_check), .need = need_page_table_check, .init = init_page_table_check, + .need_shared_flags = false, }; static struct page_table_check *get_page_table_check(struct page_ext *page_ext) _ Patches currently in -mm which might be from pasha.tatashin@soleen.com are