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[23.128.96.19]) by mx.google.com with ESMTPS id g15-20020a056a000b8f00b004fb1544bc72si12210117pfj.353.2022.04.04.20.41.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Apr 2022 20:41:54 -0700 (PDT) Received-SPF: softfail (google.com: domain of transitioning linux-kernel-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) client-ip=23.128.96.19; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=DMG38J1E; spf=softfail (google.com: domain of transitioning linux-kernel-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 5E5003FC84D; Mon, 4 Apr 2022 19:16:50 -0700 (PDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229643AbiDECSm (ORCPT + 99 others); Mon, 4 Apr 2022 22:18:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229637AbiDECSl (ORCPT ); Mon, 4 Apr 2022 22:18:41 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0CB7017A599; Mon, 4 Apr 2022 18:13:20 -0700 (PDT) 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-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RDNS_NONE,SPF_HELO_NONE,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.