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Thu, 18 Dec 2025 10:15:12 +0800 (CST) Received: from dggemv705-chm.china.huawei.com (unknown [10.3.19.32]) by mail.maildlp.com (Postfix) with ESMTPS id F115814022E; Thu, 18 Dec 2025 10:18:06 +0800 (CST) Received: from kwepemq500010.china.huawei.com (7.202.194.235) by dggemv705-chm.china.huawei.com (10.3.19.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 18 Dec 2025 10:18:06 +0800 Received: from [10.173.125.37] (10.173.125.37) by kwepemq500010.china.huawei.com (7.202.194.235) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 18 Dec 2025 10:18:05 +0800 Subject: Re: [PATCH v2 1/3] mm: fixup pfnmap memory failure handling to use pgoff To: Ankit Agrawal CC: Neo Jia , Zhi Wang , Krishnakant Jaju , Yishai Hadas , "kevin.tian@intel.com" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Vikram Sethi , Jason Gunthorpe , Matt Ochs , "jgg@ziepe.ca" , Shameer Kolothum , "alex@shazbot.org" , "akpm@linux-foundation.org" , "nao.horiguchi@gmail.com" References: <20251213044708.3610-1-ankita@nvidia.com> <20251213044708.3610-2-ankita@nvidia.com> From: Miaohe Lin Message-ID: Date: Thu, 18 Dec 2025 10:18:05 +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: 8bit X-Originating-IP: [10.173.125.37] X-ClientProxiedBy: kwepems500002.china.huawei.com (7.221.188.17) To kwepemq500010.china.huawei.com (7.202.194.235) X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: DF521C0002 X-Stat-Signature: aifym8kjh7bqcoeh59io86dw56kozsrz X-Rspam-User: X-HE-Tag: 1766024291-348880 X-HE-Meta: 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 cJDc70pq L3zfMeSe6bj8KkVzulpp7ldH7AAEBXCImoQlO7SELMtzM0DyoHNqTfagERSzNwIPs1EqB 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: List-Subscribe: List-Unsubscribe: On 2025/12/18 2:10, Ankit Agrawal wrote: >>>        i_mmap_lock_read(mapping); >>>        rcu_read_lock(); >>> @@ -2226,9 +2230,12 @@ static void collect_procs_pfn(struct address_space *mapping, >>>                t = task_early_kill(tsk, true); >>>                if (!t) >>>                        continue; >>> -             vma_interval_tree_foreach(vma, &mapping->i_mmap, pfn, pfn) { >>> -                     if (vma->vm_mm == t->mm) >>> -                             add_to_kill_pfn(t, vma, to_kill, pfn); >>> +             vma_interval_tree_foreach(vma, &mapping->i_mmap, 0, ULONG_MAX) { >>> +                     pgoff_t pgoff; >> >> IIUC, all vma will be traversed to find the final pgoff. This might not be a good idea >> because rcu lock is held and this traversal might take a really long time. Or am I miss >> something? > > Hi Miaohe, the VMAs on the registered address space will be checked. For the nvgrace-gpu > user of this API in 3/3, there are only 3 VMAs on the registered address space (that are > associated with the vfio file). Oh, I see. Thanks for your explanation. :)