From patchwork Wed Jun 8 14:14:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miaohe Lin X-Patchwork-Id: 12873571 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 B9E3CC433EF for ; Wed, 8 Jun 2022 14:14:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4E9B06B0071; Wed, 8 Jun 2022 10:14:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 499476B0072; Wed, 8 Jun 2022 10:14:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3AEB26B0073; Wed, 8 Jun 2022 10:14:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 2FEB86B0071 for ; Wed, 8 Jun 2022 10:14:32 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id EA744211E2 for ; Wed, 8 Jun 2022 14:14:31 +0000 (UTC) X-FDA: 79555263942.09.A2EE82B Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf30.hostedemail.com (Postfix) with ESMTP id CB55C8003C for ; Wed, 8 Jun 2022 14:14:30 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4LJ8MP3Cz8zQjBn; Wed, 8 Jun 2022 22:13:05 +0800 (CST) Received: from huawei.com (10.175.124.27) 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; Wed, 8 Jun 2022 22:14:25 +0800 From: Miaohe Lin To: CC: , , , Subject: [PATCH v2] mm/vmscan: don't try to reclaim freed folios Date: Wed, 8 Jun 2022 22:14:32 +0800 Message-ID: <20220608141432.23258-1-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected X-Stat-Signature: rawk4z15wmqww1noi6wwu4m3grz3y8y1 X-Rspam-User: Authentication-Results: imf30.hostedemail.com; dkim=none; spf=pass (imf30.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: CB55C8003C X-HE-Tag: 1654697670-986753 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: If folios were freed from under us, there's no need to reclaim them. Skip these folios to save lots of cpu cycles and avoid possible unnecessary disk I/O. Signed-off-by: Miaohe Lin --- v2: use folio_ref_freeze to guard against race with GUP (fast). Many thanks Matthew for pointing this out. --- mm/vmscan.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 13d34d9593bb..547ae7ae6ab1 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1610,13 +1610,19 @@ static unsigned int shrink_page_list(struct list_head *page_list, folio = lru_to_folio(page_list); list_del(&folio->lru); + nr_pages = folio_nr_pages(folio); + + if (folio_ref_count(folio) == 1 && + folio_ref_freeze(folio, 1)) { + /* folio was freed from under us. So we are done. */ + goto free_it; + } + if (!folio_trylock(folio)) goto keep; VM_BUG_ON_FOLIO(folio_test_active(folio), folio); - nr_pages = folio_nr_pages(folio); - /* Account the number of base pages */ sc->nr_scanned += nr_pages;