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 6ADC5C433EF for ; Tue, 12 Apr 2022 03:14:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F22496B0071; Mon, 11 Apr 2022 23:14:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id ED2736B0074; Mon, 11 Apr 2022 23:14:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DC0916B0075; Mon, 11 Apr 2022 23:14:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.28]) by kanga.kvack.org (Postfix) with ESMTP id CD33D6B0071 for ; Mon, 11 Apr 2022 23:14:44 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay11.hostedemail.com (Postfix) with ESMTP id 9AE8480339 for ; Tue, 12 Apr 2022 03:14:44 +0000 (UTC) X-FDA: 79346759688.06.636428E Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by imf21.hostedemail.com (Postfix) with ESMTP id D160A1C0003 for ; Tue, 12 Apr 2022 03:14:43 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.53]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4KcrM469C8zBsBk; Tue, 12 Apr 2022 11:10:24 +0800 (CST) Received: from [10.174.177.76] (10.174.177.76) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 12 Apr 2022 11:14:41 +0800 Subject: Re: [PATCH v2 2/9] mm/vmscan: remove unneeded can_split_huge_page check To: Christoph Hellwig CC: , , , , , References: <20220409093500.10329-1-linmiaohe@huawei.com> <20220409093500.10329-3-linmiaohe@huawei.com> From: Miaohe Lin Message-ID: Date: Tue, 12 Apr 2022 11:14:40 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.76] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected X-Rspam-User: X-Stat-Signature: xakc4hdif6si1fatbqmd93p96z8z3ue8 Authentication-Results: imf21.hostedemail.com; dkim=none; spf=pass (imf21.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.189 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: D160A1C0003 X-HE-Tag: 1649733283-359440 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: On 2022/4/11 22:18, Christoph Hellwig wrote: > 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. > */ > Looks better. >> + if (PageTransHuge(page) && !folio_entire_mapcount(folio) && > > Please put the folio_entire_mapcoun ont a separate line to make this a > bit more redable. Will do in next version. Many thanks for your comment! > . >