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 BC841C4167B for ; Tue, 28 Nov 2023 01:34:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 20CFE6B027C; Mon, 27 Nov 2023 20:34:55 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1BC8C6B027D; Mon, 27 Nov 2023 20:34:55 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 084A26B027F; Mon, 27 Nov 2023 20:34:55 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id EE0686B027C for ; Mon, 27 Nov 2023 20:34:54 -0500 (EST) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id AF4AD160162 for ; Tue, 28 Nov 2023 01:34:54 +0000 (UTC) X-FDA: 81505644108.29.D681CC9 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.93]) by imf23.hostedemail.com (Postfix) with ESMTP id 7BB651407C8 for ; Tue, 28 Nov 2023 01:34:48 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=hqX1pKCm; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf23.hostedemail.com: domain of ying.huang@intel.com designates 192.55.52.93 as permitted sender) smtp.mailfrom=ying.huang@intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1701135289; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=vmwx6KQ+/4j8kPbdszaHdVxC9AAfV6o/z44vIIujQ5s=; b=Tck9YkUpHWhmtroRWxEqr9c/RWZL1Ah6o2Em0bigUT5k9FmZRahpltnJt2GQwmdgneynKk RKvkOenskLiwBIQgiqN4t4v55N4gr5BJYxl97EpkluxRxnZZXQ55p5y8gTUkGmIyvzLRPp wDVnMiB4ptObNJsy9olxueTs5Mq45d0= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=hqX1pKCm; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf23.hostedemail.com: domain of ying.huang@intel.com designates 192.55.52.93 as permitted sender) smtp.mailfrom=ying.huang@intel.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1701135289; a=rsa-sha256; cv=none; b=d+sNPuk8up8Qvjz5IbtfuW6OMnwp6GghvK5jzfxYuqs0XInmpCQwA/7Yqpob6cDIvvojLS AAr8kyILDu246N3iVKhlloXxHQC3xfjeGkgBK/Y3E71g2pwEf0fSoxXTJxEF3HRlfX+hcL NltsF0rdJmKjYU6+q3vWSscpbpD1D/E= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1701135288; x=1732671288; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=Tl3AvovjiESLHonnvMLH73/h4wwAe/SrzZTRfaFMmQ0=; b=hqX1pKCmmVYd6j8U2IYU/aLcAMSp/84TlkG/8iylJEazaPh+R3wWwp4C gUNx7GmdCc8rqFLSYQuiAeduiJtk3cTbaSu+qBH4Eo7OLpSe0iabnZ1ff +7sztmmgVytNPZ4B8VUqVC1wv17I4ABxdIs4sx9MHWOIWXUrcZOYc3ZNg oze5+4Nh2jsg/XXkDNAbcMkpNhw+qFbn/37ZkTyYYZ0rfn66XqriEHgoO bHb1+2kDYqXqs7a4cdBP/Z9MCzfm+4MKvCYok+dfU8z1iE+Gl8bl/6x6h BILFQdOheTZosFkjuq5L/WeOuUwepG3k55HS0UOlgsybaTmoEjFR/CBeQ A==; X-IronPort-AV: E=McAfee;i="6600,9927,10907"; a="389982080" X-IronPort-AV: E=Sophos;i="6.04,232,1695711600"; d="scan'208";a="389982080" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Nov 2023 17:34:47 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10907"; a="744758293" X-IronPort-AV: E=Sophos;i="6.04,232,1695711600"; d="scan'208";a="744758293" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.238.208.55]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Nov 2023 17:33:06 -0800 From: "Huang, Ying" To: Michal Hocko Cc: Yosry Ahmed , Liu Shixin , Yu Zhao , Andrew Morton , Sachin Sant , Johannes Weiner , Kefeng Wang , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v10] mm: vmscan: try to reclaim swapcache pages if no swap space In-Reply-To: (Michal Hocko's message of "Mon, 27 Nov 2023 10:10:51 +0100") References: <32fe518a-e962-14ae-badc-719390386db9@huawei.com> <87msv58068.fsf@yhuang6-desk2.ccr.corp.intel.com> <87h6l77wl5.fsf@yhuang6-desk2.ccr.corp.intel.com> Date: Tue, 28 Nov 2023 09:31:06 +0800 Message-ID: <87r0ka64v9.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 7BB651407C8 X-Stat-Signature: 3b78nqsyq96pquirrfgqq45nd9cfkuu4 X-Rspam-User: X-HE-Tag: 1701135288-899711 X-HE-Meta: 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 eeTF+Yv+ Q6PnUiSJbQL03pmulQ40Fdx6twckobTdvRwLNHfBTLp2O5/Brv0FIzmdopIITCLVv4bySvHqfYBwq+jy3RGBqOtHfMxU9BQdszf0Img+E71hfWIgV37idNcBt2j7dgprH0oEl4dNRFJm67zN+Gj75nFurHc5oQDBNF0MiVI0iZToUqLz1ShQqAWMF6f3I/yf97bkyfDFS1Yx2egU= 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: List-Subscribe: List-Unsubscribe: Michal Hocko writes: > On Mon 27-11-23 10:34:46, Huang, Ying wrote: >> Michal Hocko writes: >> >> > On Thu 23-11-23 14:15:59, Huang, Ying wrote: >> >> Michal Hocko writes: >> > [...] >> >> > Yes swapcache pages are indeed more complicated but most of the time >> >> > they just go away as well, no? >> >> >> >> When we swapin a page, we will put it in swapcache too. And the page >> >> can be in that state for long time if there is more than 50% free space >> >> in the swap device. >> > >> > True, but why is that a problem? If you encounter such a swapped in page >> > on the file LRU then the page should be referened and as such should be >> > activated, no? >> >> This just means that anonymous pages in file LRU aren't temporary or >> short-term. So we need to consider that. > > Right. On the other hand we could be more aggressive when dropping the > swapcache. Is there any actual reason why we cannot try to folio_free_swap > even when mem_cgroup_swap_full == F? If there are plenty free space in swap device, why not take advantage of it? If the page is in swap cache and clean, we can discard it when it is reclaimed, or avoid to allocate swap entry for it. -- Best Regards, Huang, Ying