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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 64C15C433DF for ; Wed, 3 Jun 2020 01:28:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 45F70207F9 for ; Wed, 3 Jun 2020 01:28:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728226AbgFCB2C (ORCPT ); Tue, 2 Jun 2020 21:28:02 -0400 Received: from foss.arm.com ([217.140.110.172]:56168 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726112AbgFCB2C (ORCPT ); Tue, 2 Jun 2020 21:28:02 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5F88255D; Tue, 2 Jun 2020 18:28:01 -0700 (PDT) Received: from [192.168.0.129] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1DF4E3F6CF; Tue, 2 Jun 2020 18:27:57 -0700 (PDT) Subject: Re: [PATCH] mm/vmstat: Add events for PMD based THP migration without split To: Matthew Wilcox Cc: linux-mm@kvack.org, hughd@google.com, Naoya Horiguchi , Zi Yan , John Hubbard , Andrew Morton , linux-kernel@vger.kernel.org References: <1590118444-21601-1-git-send-email-anshuman.khandual@arm.com> <20200602150141.GN19604@bombadil.infradead.org> From: Anshuman Khandual Message-ID: <2d4634ce-9167-6ca6-fb91-f3c671fff672@arm.com> Date: Wed, 3 Jun 2020 06:56:57 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20200602150141.GN19604@bombadil.infradead.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/02/2020 08:31 PM, Matthew Wilcox wrote: > On Fri, May 22, 2020 at 09:04:04AM +0530, Anshuman Khandual wrote: >> This adds the following two new VM events which will help in validating PMD >> based THP migration without split. Statistics reported through these events >> will help in performance debugging. >> >> 1. THP_PMD_MIGRATION_SUCCESS >> 2. THP_PMD_MIGRATION_FAILURE > > There's nothing actually PMD specific about these events, is there? > If we have a THP of a non-PMD size, you'd want that reported through the > same statistic, wouldn't you? Yes, there is nothing PMD specific here and we would use the same statistics for non-PMD size THP migration (if any) as well. But is THP migration really supported for non-PMD sizes ? CONFIG_ARCH_ENABLE_THP_MIGRATION depends upon CONFIG_TRANSPARENT_HUGEPAGE without being specific or denying about possible PUD level support. Fair enough, will drop the PMD from the events and their functions.