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 C64ECC004D4 for ; Wed, 18 Jan 2023 06:01:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229640AbjARGBf (ORCPT ); Wed, 18 Jan 2023 01:01:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46892 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229492AbjARF5l (ORCPT ); Wed, 18 Jan 2023 00:57:41 -0500 Received: from mail-pj1-x1029.google.com (mail-pj1-x1029.google.com [IPv6:2607:f8b0:4864:20::1029]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F2989EC8 for ; Tue, 17 Jan 2023 21:56:38 -0800 (PST) Received: by mail-pj1-x1029.google.com with SMTP id 7-20020a17090a098700b002298931e366so1132198pjo.2 for ; Tue, 17 Jan 2023 21:56:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:from:to:cc:subject:date:message-id:reply-to; bh=LhlR+hPYyUurHWkbpxrUfFZm8eX14qkXhreB4Z6yMig=; b=XfLbG1xZL4EZLFZTy58zuiNH52eGCvzSqxO5KJyOobEc3Y4LxqeDHa6hg31tr1ytNh cLy6bd1lsUBVW5ANwI4kxY64vl8YzAjabRK1psgv4aC6Ma/eeu2At9PaJjMQ7iNHvPaL CnMFz0t5RTIdfH5/LH4DRp515KAXYQrtl7YdCbPF+sTTb+x//M2FGQJYZ2JYwNscJcyu HlY5F6TriT/KmA2+x+9rlPMlI+WDbNOEGxCWVWgn5Tc6JSNvBIRhc5a66Dud/XoByqFt YTrq3vSDhb8YJzQ5CagJEuEdcqbPGRgXcZcKOhOfwHOcwutVKQeYmvIjus46w6Gg7sWo c9vw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=LhlR+hPYyUurHWkbpxrUfFZm8eX14qkXhreB4Z6yMig=; b=eAnLpu1J5Zd5Ef9fYKuR432nCr80bKJgdDKVREG3yZ7U/tHw5eWHgdy9KSg8N0SIDz Ni62qr3/Oc8eQUpTwpAQ8HOvRMcmQ0/AyRPPa28RLmcnR+9haH4gsaDTHWwU9/yVpXEO WBQA4DnKeJ8IOmt/C3Oa4ZEL8Okd2BOBHO3Nw0+BgsPtb5SeeuYVrbmrEClIW5ur5u5j bZTIfxUB7a/DLeWMFoTRTNQU1PdDStTReH6fU/87xwPnfXmQmuTOeJgxMvCWUZp84dl8 3dc3uOs/pRpqrYCu5IavOrKqyg2gOz9Eso9pHxT8VE4Iyy+Fom9z5x9RQV+kmkSpqSmj Zvog== X-Gm-Message-State: AFqh2koQDfMkza+LgvCmaP41XUcVdmNcRxkvFZvAcw9S+Nx8GNaArHEZ FKtJxoGSvqYpAzhdmjXbHYWmyPvOkUOlnbv9 X-Google-Smtp-Source: AMrXdXtRkj4b/2S6i/McOAhb95+DUW52aqowC5BjwP72VASQbD7fAynY0yZIEEJvmkz4D90uKUNzLA== X-Received: by 2002:a05:6a20:c183:b0:b8:ca86:f3ab with SMTP id bg3-20020a056a20c18300b000b8ca86f3abmr515953pzb.2.1674021398256; Tue, 17 Jan 2023 21:56:38 -0800 (PST) Received: from [2620:15c:29:203:8fea:734b:d1f:d2d7] ([2620:15c:29:203:8fea:734b:d1f:d2d7]) by smtp.gmail.com with ESMTPSA id e9-20020aa79809000000b0058d9058fe8asm6075611pfl.103.2023.01.17.21.56.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Jan 2023 21:56:37 -0800 (PST) Date: Tue, 17 Jan 2023 21:56:36 -0800 (PST) From: David Rientjes To: Pasha Tatashin cc: rppt@kernel.org, akpm@linux-foundation.org, mhocko@suse.com, vbabka@suse.cz, david@redhat.com, quic_charante@quicinc.com, lizhe.67@bytedance.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v4] mm/page_ext: Do not allocate space for page_ext->flags if not needed In-Reply-To: <20230117202103.1412449-1-pasha.tatashin@soleen.com> Message-ID: <59557eaf-7301-d142-4549-c3e196d011d5@google.com> References: <20230117202103.1412449-1-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 17 Jan 2023, Pasha Tatashin wrote: > 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. > > Signed-off-by: Pasha Tatashin > Acked-by: Vlastimil Babka > Acked-by: David Hildenbrand Acked-by: David Rientjes