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 06477C433F5 for ; Mon, 11 Apr 2022 14:20:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241434AbiDKOWP (ORCPT ); Mon, 11 Apr 2022 10:22:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347254AbiDKOVo (ORCPT ); Mon, 11 Apr 2022 10:21:44 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E5AD632ECE for ; Mon, 11 Apr 2022 07:18:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=I/ZtqvD3xK3kfPk+73YTWW3kCWtR0aNVp8BTmJwEmOQ=; b=BkJMAp5B+oF01w97YWBr28PJby 5Ldv/lPhedaO45v1JjAhAC5FZ5lkCA0W46PaVpZKi6lcpMwApAtmXwP7EHg8ulyC3acHcnm63yHXj MRMkeMK/YWsCUX4bCDawdy26eMIXjT8gCIMV4uIprZ1F6QRdeqqG8ybjQROty59vEpLYCLNUUNTbe 3NGgUdfBBYB2mBg40gA2TPZ/sxApCLdr4gMw0dfpqpinXCY0pok60BBIWLhvbPuWC5ptPdssQ2zau OHCaTJEfQEQIFdd+Or7PaUshqxdnsk7t/Zp9W55JRuNMLsVqnZupsKErII+tF27Vmc+pbKd7zDjIm 6nBx5o4g==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1ndusN-009MLx-T8; Mon, 11 Apr 2022 14:18:43 +0000 Date: Mon, 11 Apr 2022 07:18:43 -0700 From: Christoph Hellwig To: Miaohe Lin Cc: akpm@linux-foundation.org, ying.huang@intel.com, songmuchun@bytedance.com, hch@infradead.org, willy@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/9] mm/vmscan: remove unneeded can_split_huge_page check Message-ID: References: <20220409093500.10329-1-linmiaohe@huawei.com> <20220409093500.10329-3-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220409093500.10329-3-linmiaohe@huawei.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Apr 09, 2022 at 05:34:53PM +0800, Miaohe Lin wrote: > We don't need to check can_split_folio() because folio_maybe_dma_pinned() > is checked before. It will avoid the long term pinned pages to be swapped > out. And we can live with short term pinned pages. Without can_split_folio > checking we can simplify the code. Also activate_locked can be changed to > keep_locked as it's just short term pinning. > > Suggested-by: Huang, Ying > Signed-off-by: Miaohe Lin > --- > mm/vmscan.c | 22 ++++++++-------------- > 1 file changed, 8 insertions(+), 14 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 4a76be47bed1..01f5db75a507 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -1711,20 +1711,14 @@ static unsigned int shrink_page_list(struct list_head *page_list, > goto keep_locked; > if (folio_maybe_dma_pinned(folio)) > goto keep_locked; > - if (PageTransHuge(page)) { > - /* cannot split THP, skip it */ > - if (!can_split_folio(folio, NULL)) > - goto activate_locked; > - /* > - * Split pages without a PMD map right > - * away. Chances are some or all of the > - * tail pages can be freed without IO. > - */ > - if (!folio_entire_mapcount(folio) && > - split_folio_to_list(folio, > - page_list)) > - goto activate_locked; > - } > + /* > + * Split pages without a PMD map right > + * away. Chances are some or all of the > + * tail pages can be freed without IO. > + */ This could use more of the line length and be more readable: /* * Split pages without a PMD map right away. * Chances are some or all of the tail pages * can be freed without IO. */ > + if (PageTransHuge(page) && !folio_entire_mapcount(folio) && Please put the folio_entire_mapcoun ont a separate line to make this a bit more redable.