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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B8C6C7EE2A for ; Tue, 23 May 2023 01:00:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234402AbjEWBAN (ORCPT ); Mon, 22 May 2023 21:00:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235016AbjEWA7u (ORCPT ); Mon, 22 May 2023 20:59:50 -0400 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C845BDB for ; Mon, 22 May 2023 17:57:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1684803437; x=1716339437; h=from:to:cc:subject:references:date:in-reply-to: message-id:mime-version; bh=PaQ+uFejefUKDhkjELmrTi97YlZDHlfjttd0/Isxric=; b=mmgExzJpRO1eg885plv+eqcW6YX/K/M+SS9sjmlFy6pzMym1ZfweQK7x akiD0kYhzVVhPmVlcbSjCYiBEez+CU4Sg04hzYwgh9I4YgeD53sCXf5X3 0dr8x3wkh0ijEMajQrQMBYxhu9NxGA/bgvIK4zSlIRbEjY6QBAa9L3AvE PgZsuDi2vTJtmPNu6tyT5PqTGY7Yk2fGdAImRJVJOMStyqIpx24IZa+xC QfHKUdpiUFB/HPd4oNFSGtyeSd5rPIZfAMAjue9TyJ0YmyuTNP1nbfw3C tZAqowDgJ9AuJ/i5b3aQf4fartVnzMmPkW7OvwTsMBPKC9wcGfs+af/KU Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10718"; a="350596431" X-IronPort-AV: E=Sophos;i="6.00,184,1681196400"; d="scan'208";a="350596431" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 May 2023 17:57:17 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10718"; a="654154365" X-IronPort-AV: E=Sophos;i="6.00,184,1681196400"; d="scan'208";a="654154365" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.238.208.55]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 May 2023 17:57:14 -0700 From: "Huang, Ying" To: David Hildenbrand Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hugh Dickins , Johannes Weiner , Matthew Wilcox , Michal Hocko , Minchan Kim , Tim Chen , Yang Shi , Yu Zhao Subject: Re: [PATCH -V2 4/5] swap: remove get/put_swap_device() in __swap_duplicate() References: <20230522070905.16773-1-ying.huang@intel.com> <20230522070905.16773-5-ying.huang@intel.com> <9cbd93e0-721a-01c2-14dd-87f89363a830@redhat.com> Date: Tue, 23 May 2023 08:56:11 +0800 In-Reply-To: <9cbd93e0-721a-01c2-14dd-87f89363a830@redhat.com> (David Hildenbrand's message of "Mon, 22 May 2023 14:06:05 +0200") Message-ID: <87o7mbyifo.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org David Hildenbrand writes: > On 22.05.23 09:09, Huang Ying wrote: >> __swap_duplicate() is called by >> - swap_shmem_alloc(): the page lock of the swap cache is held. > > page lock of the swap cache? Did you really mean to say that or am I > confused? > > "Page lock of the page that is in the swap cache?" Sorry for my poor English. Or make it shorter? "the folio in the swap cache is locked" Best Regards, Huang, Ying >> - copy_nonpresent_pte() -> swap_duplicate() and try_to_unmap_one() >> -> >> swap_duplicate(): the page table lock is held. >> - __read_swap_cache_async() -> swapcache_prepare(): enclosed with >> get/put_swap_device() in __read_swap_cache_async() already. >> So, it's safe to remove get/put_swap_device() in __swap_duplicate().