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 4BD85C00140 for ; Fri, 29 Jul 2022 02:02:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A68228E0001; Thu, 28 Jul 2022 22:02:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9F0946B0072; Thu, 28 Jul 2022 22:02:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 869FC8E0001; Thu, 28 Jul 2022 22:02:54 -0400 (EDT) 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 739C36B0071 for ; Thu, 28 Jul 2022 22:02:54 -0400 (EDT) Received: from smtpin31.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 37574A139E for ; Fri, 29 Jul 2022 02:02:54 +0000 (UTC) X-FDA: 79738489068.31.172A07D Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by imf09.hostedemail.com (Postfix) with ESMTP id 4A19B1400CC for ; Fri, 29 Jul 2022 02:02:53 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.57]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4Lv9gt3dSqz1M8Yb; Fri, 29 Jul 2022 09:59:54 +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; Fri, 29 Jul 2022 10:02:48 +0800 Subject: Re: [RFC PATCH v4 7/8] hugetlb: create hugetlb_unmap_file_folio to unmap single file folio To: Mike Kravetz , , CC: Muchun Song , Michal Hocko , Peter Xu , Naoya Horiguchi , David Hildenbrand , "Aneesh Kumar K . V" , Andrea Arcangeli , "Kirill A . Shutemov" , Davidlohr Bueso , Prakash Sangappa , James Houghton , Mina Almasry , Pasha Tatashin , Axel Rasmussen , Ray Fucillo , Andrew Morton References: <20220706202347.95150-1-mike.kravetz@oracle.com> <20220706202347.95150-8-mike.kravetz@oracle.com> From: Miaohe Lin Message-ID: <3557d5a9-231c-4007-3e7e-5a7bf34ecaa8@huawei.com> Date: Fri, 29 Jul 2022 10:02:48 +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: <20220706202347.95150-8-mike.kravetz@oracle.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.76] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=none; spf=pass (imf09.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.255 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1659060173; a=rsa-sha256; cv=none; b=T4XYLdHA3nz+0k++ct2/0bFTl4g8Ud2jpVCd3C5KsVNJesB2VeLQToNZyDMVEfoXw/2qIu CB3e8l8TjvvcJvyJHuu+9IuFWcp1gc9HGi52sY+fp3CeJym1rVYpmBXCCVtE0JeFXE3XT7 DDPPGCxAofKOZvKYMN3c2ErWdv1e5Go= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1659060173; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=PyXGYD0U88+uz/hjg+0BjLhXENNnbtKcxWAT2pfywW8=; b=263NpOE19BdOcXusrNk3XXJxT5i3kqELlKnS3cuU95TUuf/x8taXMrOpdDZ87i9Ry+Q8zA uTiDp+w2n5Dw2p5wAdJEK4fCp/SqdHhJHotQ2jjXMANDtDFtboGhHkpLVZI+Eb8hc6BRSZ XGpM9wTI4+VDcxIXsNtrMM34RknDMd8= X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 4A19B1400CC Authentication-Results: imf09.hostedemail.com; dkim=none; spf=pass (imf09.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.255 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-Stat-Signature: 5yep4m4e35wu73kq49ubce1x1b7i6dyj X-Rspam-User: X-HE-Tag: 1659060173-701668 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 2022/7/7 4:23, Mike Kravetz wrote: > Create the new routine hugetlb_unmap_file_folio that will unmap a single > file folio. This is refactored code from hugetlb_vmdelete_list. It is > modified to do locking within the routine itself and check whether the > page is mapped within a specific vma before unmapping. > > This refactoring will be put to use and expanded upon in a subsequent > patch adding vma specific locking. > > Signed-off-by: Mike Kravetz > --- > fs/hugetlbfs/inode.c | 124 +++++++++++++++++++++++++++++++++---------- > 1 file changed, 95 insertions(+), 29 deletions(-) > > diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c > index 31bd4325fce5..0eac0ea2a245 100644 > --- a/fs/hugetlbfs/inode.c > +++ b/fs/hugetlbfs/inode.c > @@ -396,6 +396,94 @@ static int hugetlbfs_write_end(struct file *file, struct address_space *mapping, > return -EINVAL; > } > > +/* > + * Called with i_mmap_rwsem held for inode based vma maps. This makes > + * sure vma (and vm_mm) will not go away. We also hold the hugetlb fault > + * mutex for the page in the mapping. So, we can not race with page being > + * faulted into the vma. > + */ > +static bool hugetlb_vma_maps_page(struct vm_area_struct *vma, > + unsigned long addr, struct page *page) > +{ > + pte_t *ptep, pte; > + > + ptep = huge_pte_offset(vma->vm_mm, addr, > + huge_page_size(hstate_vma(vma))); > + > + if (!ptep) > + return false; > + > + pte = huge_ptep_get(ptep); > + if (huge_pte_none(pte) || !pte_present(pte)) > + return false; > + > + if (pte_page(pte) == page) > + return true; > + > + return false; /* WTH??? */ I'm sorry but what does WTH means? IIUC, this could happen if pte_page is a COW-ed private page? vma_interval_tree_foreach doesn't exclude the private mapping even after cow? Except from above (trivial one), this patch looks good to me. Thanks.