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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 17A00C47082 for ; Tue, 8 Jun 2021 12:33:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 002AF6127A for ; Tue, 8 Jun 2021 12:33:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232683AbhFHMfE (ORCPT ); Tue, 8 Jun 2021 08:35:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232635AbhFHMfD (ORCPT ); Tue, 8 Jun 2021 08:35:03 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF7B3C061574 for ; Tue, 8 Jun 2021 05:33:10 -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=YSGQEI1WX6YiXANPfcZHnOB1Uu7nxLS3hbjqa7fmpSI=; b=NqHKRKUraLAIML21HZSAmknZ4F VU5XAZc1pxC1JYcy9gVMgNVLmzW0kR8IhWQOQCr2WAc8FpmKcoi/Lv+Sj0J3I61+d5r3FQXyk2gar I/HUhvhoeZr/WgTYH6NnOvkdF8J4uCni+tx1Z0TXe+I36WvE/Yjt0M8y7C7lwOOwOi3OYL3TiHGm5 KSomQovXbqyDh8p9A3jwiJkkNpowT3Xae/S61GX7UFaTq23bBlPF/1GxUz/xxODH2dqV2AiC+SAx8 +KpXfOtPcWdWemeJ0sglnemOGsPokjv2ywQSdycZUwXg/bq4LK6QqJLG9eXh8cBdU//QVm4mFRJkH z19eDUYw==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lqau6-00Gw37-10; Tue, 08 Jun 2021 12:32:33 +0000 Date: Tue, 8 Jun 2021 13:32:21 +0100 From: Matthew Wilcox To: "Kirill A. Shutemov" Cc: Xu Yu , linux-mm@kvack.org, linux-kernel@vger.kernel.org, hughd@google.com, akpm@linux-foundation.org, gavin.dg@linux.alibaba.com Subject: Re: [PATCH v2] mm, thp: use head page in __migration_entry_wait Message-ID: References: <20210608120026.ugfh72ydjeba44bo@box.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210608120026.ugfh72ydjeba44bo@box.shutemov.name> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 08, 2021 at 03:00:26PM +0300, Kirill A. Shutemov wrote: > But there's one quirk: if split succeed we effectively wait on wrong > page to be unlocked. And it may take indefinite time if split_huge_page() > was called on the head page. Hardly indefinite time ... callers of split_huge_page_to_list() usually unlock the page soon after. Actually, I can't find one that doesn't call unlock_page() within a few lines of calling split_huge_page_to_list().