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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86F5EC6FA89 for ; Fri, 2 Sep 2022 08:08:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235665AbiIBIIR (ORCPT ); Fri, 2 Sep 2022 04:08:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235656AbiIBIIO (ORCPT ); Fri, 2 Sep 2022 04:08:14 -0400 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CFB2CB729D; Fri, 2 Sep 2022 01:08:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1662106093; x=1693642093; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=B8ofpabz8OrAnYU/UuLj8SXDHWJrJaWAuJy/DtjxDr4=; b=f+fmDK0j90DlwvSGcJwj5nnjns+qLlt2Zdh4/MJv2WGdmnXMlLVg8Yob agC+n+gyEg3g3S8ZR92k13Z4qgXTeClo6MHrQwIYTFwaCQPbZsSi3GsN7 g/FLMzDZsXCLkk/xpz6KgcYGaKiac3x1FcQmNRpqXVeKBa6j/uJ8Ii1fs Z9hG27tQpN8kIZVCEkYVc+M87adxxMBJ5IsGauKM7NboJ0WFTeBL/uRsf b1roUlu4PTGS7u5NFqpGsLJ9J2BmE0ee9wO6PgqkxD3bs+n/c3pHmbBRa c3tB+LYiP+wMPN1wE7aeBk8T5T6uj6TDb7Y///VhLGCkRya5IfiE5C+dM A==; X-IronPort-AV: E=McAfee;i="6500,9779,10457"; a="282915926" X-IronPort-AV: E=Sophos;i="5.93,283,1654585200"; d="scan'208";a="282915926" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Sep 2022 01:08:13 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,283,1654585200"; d="scan'208";a="589987118" Received: from liuzhao-optiplex-7080.sh.intel.com ([10.239.160.132]) by orsmga006.jf.intel.com with ESMTP; 02 Sep 2022 01:08:10 -0700 From: Zhao Liu To: Alex Shi , Yanteng Si , Jonathan Corbet , Wu XiangCheng , Mike Rapoport , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Ira Weiny , "Fabio M . De Francesco" , Zhenyu Wang , Zhao Liu Subject: [PATCH] Documentation/zh_CN: add latest kmap_local_page translation Date: Fri, 2 Sep 2022 16:13:04 +0800 Message-Id: <20220902081304.2259706-1-zhao1.liu@linux.intel.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zhao Liu Translate the lastest description of kmap_local_page into Chinese. The translation is based on these commits: commit 516ea046ec555 ("Documentation/mm: don't kmap*() pages which can't come from HIGHMEM") commit 6b3afe2eeec27 ("Documentation/mm: avoid invalid use of addresses from kmap_local_page()") commit 84b86f6054c42 ("Documentation/mm: rrefer kmap_local_page() and avoid kmap()") commit a9e9c93966afd ("Documentation/mm: add details about kmap_local_page() and preemption") Suggested-by: Ira Weiny Suggested-by: Fabio M. De Francesco Signed-off-by: Zhao Liu --- Suggested by credits. Ira: Referred to his task document. Fabio: Referred to his work on the original English document. --- .../translations/zh_CN/mm/highmem.rst | 20 ++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/Documentation/translations/zh_CN/mm/highmem.rst b/Documentation/translations/zh_CN/mm/highmem.rst index f74800a6d9a7..ac4c86ed74d8 100644 --- a/Documentation/translations/zh_CN/mm/highmem.rst +++ b/Documentation/translations/zh_CN/mm/highmem.rst @@ -58,14 +58,28 @@ 在可行的情况下，这个函数应该比其他所有的函数优先使用。 这些映射是线程本地和CPU本地的，这意味着映射只能从这个线程中访问，并且当映射处于活动状 - 态时，该线程与CPU绑定。即使线程被抢占了（因为抢占永远不会被函数禁用），CPU也不能通过 - CPU-hotplug从系统中拔出，直到映射被处理掉。 + 态时，该线程与CPU绑定。即使抢占永远不会被这个函数禁用，CPU也不能通过CPU-hotplug从系 + 统中拔出，直到映射被处理掉。 - 在本地的kmap区域中采取pagefaults是有效的，除非获取本地映射的上下文由于其他原因不允许 + 在本地的kmap区域中获取pagefaults是有效的，除非获取本地映射的上下文由于其他原因不允许 这样做。 + 如前所述，pagefault和抢占永远不会被禁用。不需要禁用抢占，因为当上下文切换到不同的任务 + 时，传出任务的映射会被保存，而传入任务的映射会被恢复。 + kmap_local_page()总是返回一个有效的虚拟地址，并且假定kunmap_local()不会失败。 + 在CONFIG_HIGHMEM=n内核和低内存页面上，这将返回直接映射的虚拟地址。只有真正的高内存页 + 面会被临时映射。因此，用户可以为已知不是来自ZONE_HIGHMEM的页面调用普通的 + page_address()，但是，使用kmap_local_page() / kunmap_local()总是安全的。 + + 虽然它比kmap()快得多，但对于高内存情况，它带有指针有效性的限制。和kmap()映射相反，本地 + 映射仅在调用者的上下文中有效，并不能被交给其他的上下文。这意味着用户必须绝对确保返回的地址 + 仅在映射它的线程的本地使用。 + + 大多数代码可以设计为使用线程本地映射。因此，用户应该尝试这样去设计他们的代码，在地址会被使 + 用的同一线程中映射页面来避免使用kmap()，并且更倾向于去使用kmap_local_page()。 + 嵌套kmap_local_page()和kmap_atomic()映射在一定程度上是允许的（最多到KMAP_TYPE_NR）， 但是它们的调用必须严格排序，因为映射的实现是基于堆栈的。关于如何管理嵌套映射的细节， 请参见kmap_local_page() kdocs（包含在 "函数 "部分）。 -- 2.34.1