From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1316154-1518053803-2-15231161157587992906 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, FREEMAIL_FORGED_FROMDOMAIN 0.195, FREEMAIL_FROM 0.001, HEADER_FROM_DIFFERENT_DOMAINS 0.001, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='com', MailFrom='org' X-Spam-charsets: plain='us-ascii' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1518053802; b=bpFKqTrjFJzt12FCPRS+9urYwk7KXVxGfvsSMXGDwa0YM9a hijzcj8flqHTijDxXK4AL2RBjiXKXViDKZDQk+FDvLtAXKX6S+TzS6cT1YP7y8FE ad/3Ipj9XVG+CbkHRCcHwHsaYsSSQvIpRF4/bRUyWQxIJH4nzdPWQx76EAdEhU2h J2ryybBua4FOVWbGSxnVZZkMyYWQUAHdHTVazsPim0RJ3ZtqCWSp+1/T9E75LGd3 G0giA0QjHnffIp/HdC1dJ9GYHM5sT4p+2yq6OE65mvkoWSu0ToA63OHNF9vnkR77 4qkHTuTpKTYv9CHsk9MmkosCttvbkGFQrWJt2og== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to:sender :list-id; s=arctest; t=1518053802; bh=ddJIqtBWrQF3BDfvwSSxQO3IMW 1ukNALsQQWXP/uLjU=; b=P5hCiPjYMGc/RNE/jVPfdb79DdhFu+ZPn3ZRjRJY7K UnxwO6xHJv3YPKmYQSJ2PX5wzJVZ2AnnYGgRcwP74ghBSaNd4g7HZvfHSH/HGZcb 67C9bUj+FeXDD+TY61md97GENrGmACZ5LVbZPCL0tIAnAB/6Vlp8RMsrhA7JZDpO IlBK5FPNvA+1q+2GpwP6PPv7q2vwPwtjqSuuJ9B9wPDZDcAqaC15Hll2XxeBq2XR Ezm/JE7xfMTa/iz5yDIqQCiTsf0G8sJNwxyNksF3SB4qtWJDWM44Y8J9ZaUt7R8L Q595gDGyM1Ew6mbHyaV3+pa+qSWDFlgQhgcn0PG+TB2w== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=gmail.com header.i=@gmail.com header.b=GmS385En x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=20161025; dmarc=pass (p=none,has-list-id=yes,d=none) header.from=gmail.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=ZzwJ2P7U; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=gmail.com header.result=pass header_is_org_domain=yes Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=gmail.com header.i=@gmail.com header.b=GmS385En x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=20161025; dmarc=pass (p=none,has-list-id=yes,d=none) header.from=gmail.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=ZzwJ2P7U; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=gmail.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750815AbeBHBgl (ORCPT ); Wed, 7 Feb 2018 20:36:41 -0500 Received: from mail-pg0-f48.google.com ([74.125.83.48]:42695 "EHLO mail-pg0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750767AbeBHBgk (ORCPT ); Wed, 7 Feb 2018 20:36:40 -0500 X-Google-Smtp-Source: AH8x225AKLxOvaiRN9aOJfPjWxNqS+WNOuWIldYIJLLxApTIenMtrzG4Z3sC7iArX7+jQ78wzvpa4w== Date: Thu, 8 Feb 2018 10:36:35 +0900 From: Sergey Senozhatsky To: Andrew Morton , Minchan Kim Cc: "Huang, Ying" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Konrad Rzeszutek Wilk , Dan Streetman , Seth Jennings , Tetsuo Handa , Shaohua Li , Michal Hocko , Johannes Weiner , Mel Gorman , Shakeel Butt , stable@vger.kernel.org, Sergey Senozhatsky Subject: Re: [PATCH -mm -v2] mm, swap, frontswap: Fix THP swap if frontswap enabled Message-ID: <20180208013635.GA596@jagdpanzerIV> References: <20180207070035.30302-1-ying.huang@intel.com> <20180207130534.259cd71a595c6275b2da38d3@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180207130534.259cd71a595c6275b2da38d3@linux-foundation.org> User-Agent: Mutt/1.9.3 (2018-01-21) Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On (02/07/18 13:05), Andrew Morton wrote: [..] > hm. This is assuming that "cluster==true" means "this is thp swap". > That's presently true, but is it appropriate that get_swap_pages() is > peeking at "cluster" to work out why it is being called? > > Or would it be cleaner to do this in get_swap_page()? Something like > > --- a/mm/swap_slots.c~a > +++ a/mm/swap_slots.c > @@ -317,8 +317,11 @@ swp_entry_t get_swap_page(struct page *p > entry.val = 0; > > if (PageTransHuge(page)) { > - if (IS_ENABLED(CONFIG_THP_SWAP)) > - get_swap_pages(1, true, &entry); > + /* Frontswap doesn't support THP */ > + if (!frontswap_enabled()) { > + if (IS_ENABLED(CONFIG_THP_SWAP)) > + get_swap_pages(1, true, &entry); > + } > return entry; > } I have proposed exactly the same thing [1], Minchan commented that it would introduce frontswap dependency to swap_slots.c [2]. Which is true, but I'd still probably prefer to handle it all in get_swap_page. Minchan, any objections? [1] https://marc.info/?l=linux-mm&m=151791052007719&w=2 [2] https://marc.info/?l=linux-mm&m=151792646812617&w=2 -ss