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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73E32C43219 for ; Fri, 1 Oct 2021 12:00:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6166861AA9 for ; Fri, 1 Oct 2021 12:00:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354203AbhJAMBn (ORCPT ); Fri, 1 Oct 2021 08:01:43 -0400 Received: from mail-vs1-f42.google.com ([209.85.217.42]:37424 "EHLO mail-vs1-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230510AbhJAMBl (ORCPT ); Fri, 1 Oct 2021 08:01:41 -0400 Received: by mail-vs1-f42.google.com with SMTP id f2so10080626vsj.4; Fri, 01 Oct 2021 04:59:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=WR3+MFp1ibU3x0ZkDpZ824RbuuABr+gcaM86vEqsRNo=; b=BRh0WV659CFjH7+kssWg1sAcI9VqDTEcTsFY/uFEZGBqu8/7+TuPXPinTIa1/wJrnS iaiez80AjRm92GWRM12qn63IJbZWUGT0/w3QUZfF/LoPpHlu7AptnSbeGqx7+OzRfDiq vd84ZzWCt2JSrUYQI8GfWXfJmeDIGDU/2c8+qhAd6UvHDFFhz6Jv3ylVr9znvDop++J5 NOOuGU2OGRtbpPd/1ZPSaW6WlpmNkjzv9sAZ2y37s4b5seSmb3yqu9nyJAt/GVjhXjI2 xOvbBq4ekPSAQbKG3E2xUx5wbbdIkzlhmhLs39t4PKwsdamsWbcUDmlYomyKH1M6cYou UR3w== X-Gm-Message-State: AOAM532SJsWlWQWH3XCjBJyJ+ckkJqC43di0zIo8UqKsqo5CnnhP+44f Q0rjRhKskBdTAkGHK7jnL2gFKcvhb/Vn2R1VGIeDsmsBGiY= X-Google-Smtp-Source: ABdhPJyx7zg5kQJYsNSRRoL0YNyux79qxJGzafd5NYmhZJ2xCJLygfQPVXUiK/lmOsYXRavGy+aJ1Mf8eL4lb+ZaszY= X-Received: by 2002:a67:c295:: with SMTP id k21mr790199vsj.37.1633089597139; Fri, 01 Oct 2021 04:59:57 -0700 (PDT) MIME-Version: 1.0 References: <20210928235635.1348330-1-willmcvicker@google.com> <7766faf8-2dd1-6525-3b9a-8ba790c29cff@canonical.com> In-Reply-To: From: Geert Uytterhoeven Date: Fri, 1 Oct 2021 13:59:45 +0200 Message-ID: Subject: Re: [PATCH v2 00/12] arm64: Kconfig: Update ARCH_EXYNOS select configs To: Olof Johansson Cc: Saravana Kannan , Will McVicker , Krzysztof Kozlowski , Russell King , Catalin Marinas , Will Deacon , Michael Turquette , Stephen Boyd , Sylwester Nawrocki , Tomasz Figa , Chanwoo Choi , Linus Walleij , Alessandro Zummo , Alexandre Belloni , John Stultz , Thomas Gleixner , Lee Jones , "Cc: Android Kernel" , Linux ARM , Linux Kernel Mailing List , linux-samsung-soc , linux-clk , "open list:GPIO SUBSYSTEM" , linux-rtc@vger.kernel.org, Arnd Bergmann Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Olof, On Fri, Oct 1, 2021 at 7:36 AM Olof Johansson wrote: > A much more valuable approach would be to work towards being able to > free up memory by un-probed drivers at the end of boot. That would > possibly benefit all platforms on all architectures. We used to have such a functionality in arch/ppc (not arch/powerpc!), where code/data could be tagged __prep, __chrp, or __pmac, to put it in a special section, and to be freed with initdata when unused. It was removed in v2.6.15[1], as the savings weren't worth the hassle. In a more fragmented space like arm the memory lost due to alignment of the sections would be even more substantial. Another problem is to know when is the end of the boot, especially with deferred probing. [1] 6c45ab992e4299c8 ("[PATCH] powerpc: Remove section free() and linker script bits") Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds