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Mon, 16 Mar 2026 20:05:25 +0800 (CST) Received: from dggpemf500012.china.huawei.com (unknown [7.185.36.8]) by mail.maildlp.com (Postfix) with ESMTPS id E7E7A40538; Mon, 16 Mar 2026 20:10:45 +0800 (CST) Received: from huawei.com (10.50.87.63) by dggpemf500012.china.huawei.com (7.185.36.8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Mon, 16 Mar 2026 20:10:45 +0800 From: Lin Ruifeng To: , , , , , , , , , , , , CC: , Subject: [RFC PATCH] mm/mempolicy: NUMA mempolicy mismatch during remote access Date: Mon, 16 Mar 2026 20:04:24 +0800 Message-ID: <20260316120424.1535575-1-linruifeng4@huawei.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.50.87.63] X-ClientProxiedBy: kwepems100001.china.huawei.com (7.221.188.238) To dggpemf500012.china.huawei.com (7.185.36.8) X-Rspam-User: X-Rspamd-Queue-Id: 9E7451C0011 X-Rspamd-Server: rspam08 X-Stat-Signature: y19o55szednm7eg5khpdpjuwahw64y1h X-HE-Tag: 1773663053-72422 X-HE-Meta: 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 OOAwpEpa QuWJ3YXW66iD8Mf8jI4j7viP6AFwLV2hlXiVMoD3kyjmthszHHgzeI7tKcuSlk5RVAWnU Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: I'd like to report an issue in the SVA I/O Page Fault (IOPF) handling path: a NUMA memory policy mismatch caused by deferred workqueue processing. When hardware triggers a page fault via the IOMMU SVA mechanism, it's handled asynchronously by a kworker thread. Although the fault handler correctly uses the original process's mm_struct for address space mapping, the physical page allocation (e.g., in do_anonymous_page()) still depends on current->mempolicy. Since current here is the kworker, not the original user process, any task-level NUMA policy (e.g., set_mempolicy() or numactl --membind) is completely ignored. Instead, allocation follows the kworker's default policy, which may run on a different NUMA node. A similar issue was also discussed in [1]. I was wondering if you might have any suggestions on how to address this issue. Link: https://lore.kernel.org/linux-mm/e2d5f3a5-f6f1-4567-a162-a0e814292738@asahilina.net/ Signed-off-by: Lin Ruifeng 2.43.0