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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83DAAC433F5 for ; Tue, 5 Apr 2022 00:17:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E49516B0071; Mon, 4 Apr 2022 20:17:24 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DF4816B0073; Mon, 4 Apr 2022 20:17:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CBDA66B0074; Mon, 4 Apr 2022 20:17:24 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0106.hostedemail.com [216.40.44.106]) by kanga.kvack.org (Postfix) with ESMTP id B90A06B0071 for ; Mon, 4 Apr 2022 20:17:24 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 7908393D61 for ; Tue, 5 Apr 2022 00:17:14 +0000 (UTC) X-FDA: 79320910788.24.FC9C56F Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf19.hostedemail.com (Postfix) with ESMTP id 9B20A1A0007 for ; Tue, 5 Apr 2022 00:17:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=RQe/1RGyLtJutAfIYXbUCaVRkV5ue8WY6oN5rza5dGM=; b=DMG38J1E2P6kQfgNZCEepEnC0l BfkfspbskxZO/vvhafQL/m/VsO+CVwdVcxwhGTo0/TW1vYeg9l2ZYKAkSWjy7LFK+fkpZRlWI+KZV JJrcbErzQESO95G5fma4qmgh1T7qKpsoaTWeZQJG1f7jwAh9yL4QMQvEeKzVXSkS0YjBW05cqF96l KS29M0DxM0FIw4gZYZmD6wCEyzZ5dLseXO0MKzYyIHau8z30pnH/t5otixn3ekVyaD+a4oph1Fyo9 +202fK51u+5r+F2IEt2amOyHkk8r+QN+nkeXygFHObiJD32Q9vkRkrosk/DSBifL2Ipp0Xu0l4vPT oehzjoaQ==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nbWsG-006CDX-VD; Tue, 05 Apr 2022 00:16:45 +0000 Date: Tue, 5 Apr 2022 01:16:44 +0100 From: Matthew Wilcox To: Yang Shi Cc: vbabka@suse.cz, kirill.shutemov@linux.intel.com, linmiaohe@huawei.com, songliubraving@fb.com, riel@surriel.com, ziy@nvidia.com, tytso@mit.edu, akpm@linux-foundation.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [v3 PATCH 0/8] Make khugepaged collapse readonly FS THP more consistent Message-ID: References: <20220404200250.321455-1-shy828301@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220404200250.321455-1-shy828301@gmail.com> X-Stat-Signature: gp5roybrpk7nkaxeu6bw1f6kso1khkd5 Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=DMG38J1E; spf=none (imf19.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 9B20A1A0007 X-HE-Tag: 1649117833-278572 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Apr 04, 2022 at 01:02:42PM -0700, Yang Shi wrote: > The readonly FS THP relies on khugepaged to collapse THP for suitable > vmas. But it is kind of "random luck" for khugepaged to see the > readonly FS vmas (see report: https://lore.kernel.org/linux-mm/00f195d4-d039-3cf2-d3a1-a2c88de397a0@suse.cz/) since currently the vmas are registered to khugepaged when: I still don't see the point. The effort should be put into supporting large folios, not in making this hack work better.