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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2D09C4332D for ; Mon, 15 Mar 2021 12:08:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6E30664ED2 for ; Mon, 15 Mar 2021 12:08:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230092AbhCOMIB (ORCPT ); Mon, 15 Mar 2021 08:08:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48676 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229830AbhCOMHr (ORCPT ); Mon, 15 Mar 2021 08:07:47 -0400 Received: from mail-lf1-x133.google.com (mail-lf1-x133.google.com [IPv6:2a00:1450:4864:20::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E2FFC061574 for ; Mon, 15 Mar 2021 05:07:46 -0700 (PDT) Received: by mail-lf1-x133.google.com with SMTP id q25so56410652lfc.8 for ; Mon, 15 Mar 2021 05:07:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=xcBEaoMgOUg6Oq+1NZ62LHPAUIVElSEob3K7B1GsgBA=; b=fnukcSh6bz8KDNhtKbz34zCgeiqi2Wit0RLRnJO2jCJzPRTPlNg7l1ilMm5hOIYhgZ 4yFTgcNbi2hqFx01FWQwquRN5uLKXA/yb+J+PjomR69PnmiK4oG33+3c010SeyqY3b1V Tj14GcgJ/xu+TmpjZDPgR48G+e1seHknp2rQPkBt1l9vOBwZUmaypRcFcwwVe11oUPrd p2jR4PGu8G5H+noyCy8uUsmt2m4alcAI8kpq7Xv/8GztX8H/BcbPSY1CqtUxhsAYJpnr 0zoc3x3RZzudcIrlR6bKHnNcchzny8xqNiNxrPv5AO9oG3NvemR4g1kuDiKqmRnUuhtZ F9KA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=xcBEaoMgOUg6Oq+1NZ62LHPAUIVElSEob3K7B1GsgBA=; b=smU1fikdekUiJwI9Ba+iEDZ43sB/hmkYVD7nR7nDDASSQOYUkFtQao1Igg2KVoyHDG CqPaMgXwyiHLqwlj9OVB9g1z8usoygDCNCdASEDWW7LcN76WBUnnehmkfz1TTaQUMuSF HYbTb/EuvZ8aemamk/yTnPX+wcDjWtfeXrngDBiQF51DncNLl1lCvuMQowjusz/JG027 RACVzZoaaeb5vha0zJOH3ZYGktBTto5Cm+apkB+p/JaCkIOI8TLg3gu7bkwCoHL7asw+ TePE4kcsaIQdQp7P2sxjtgLjgJbYE6oR0xi2Y7kLNGmGpfx4kdtslcDTnn+VzuC0Ou1n WHsw== X-Gm-Message-State: AOAM533YiZnwL2kFZ5JMDCNXSQC98ccP2vjbG7RaQJVpKwzhEpGGLURo DzNam9nKv7LCxz/TuVD8+jZU+Q== X-Google-Smtp-Source: ABdhPJx7lPgJ8wy+Ez31fyuhgQCC28oY7wc9fb7gDEwMPYVgovdXw1VtMnh+D+uQSvEDn+jgeySKuQ== X-Received: by 2002:ac2:5d52:: with SMTP id w18mr7553649lfd.28.1615810065040; Mon, 15 Mar 2021 05:07:45 -0700 (PDT) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id y14sm2639094lfl.165.2021.03.15.05.07.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Mar 2021 05:07:44 -0700 (PDT) Received: by box.localdomain (Postfix, from userid 1000) id 7EFB910246E; Mon, 15 Mar 2021 15:07:48 +0300 (+03) Date: Mon, 15 Mar 2021 15:07:48 +0300 From: "Kirill A. Shutemov" To: Zi Yan Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, "Kirill A . Shutemov" , Andrew Morton , Shuah Khan , John Hubbard , Sandipan Das , David Hildenbrand , Yang Shi , Mika Penttila Subject: Re: [PATCH v3] mm: huge_memory: a new debugfs interface for splitting THP tests. Message-ID: <20210315120748.nuw5vk6grmfacact@box> References: <20210312005712.116888-1-zi.yan@sent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210312005712.116888-1-zi.yan@sent.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 11, 2021 at 07:57:12PM -0500, Zi Yan wrote: > From: Zi Yan > > We do not have a direct user interface of splitting the compound page > backing a THP But we do. You expand it. > and there is no need unless we want to expose the THP > implementation details to users. Make /split_huge_pages accept > a new command to do that. > > By writing ",," to > /split_huge_pages, THPs within the given virtual address range > from the process with the given pid are split. It is used to test > split_huge_page function. In addition, a selftest program is added to > tools/testing/selftests/vm to utilize the interface by splitting > PMD THPs and PTE-mapped THPs. > Okay, makes sense. But it doesn't cover non-mapped THPs. tmpfs may have file backed by THP that mapped nowhere. Do we want to cover this case too? Maybe have PID:,, and FILE:,, ? -- Kirill A. Shutemov