From patchwork Mon Apr 12 06:41:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gal Pressman X-Patchwork-Id: 12196925 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-23.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17F50C433ED for ; Mon, 12 Apr 2021 06:42:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E225F6008E for ; Mon, 12 Apr 2021 06:42:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231386AbhDLGma (ORCPT ); Mon, 12 Apr 2021 02:42:30 -0400 Received: from smtp-fw-6001.amazon.com ([52.95.48.154]:41652 "EHLO smtp-fw-6001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229524AbhDLGma (ORCPT ); Mon, 12 Apr 2021 02:42:30 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1618209734; x=1649745734; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=PTut39yWoiWxos/LTODt7JPHIlSHSGcFpEf15jIk2R8=; b=fwJ8hwoZv74/ZjVyC9AB02DMGhXQkRv/CZG1gORSgRrDKjpzTDYn0gxs KgQW1V+r2CUnxsaWPUG+vlFtTFjWHgfVaRqZWRoc43U0SagObi0LRAtND kalWbkQfLMzdCi4n7e+KolaDm/FB2junwywT/S9KOuIdBo58u1vXm7GLT A=; X-IronPort-AV: E=Sophos;i="5.82,214,1613433600"; d="scan'208";a="106848578" Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-1e-27fb8269.us-east-1.amazon.com) ([10.43.8.2]) by smtp-border-fw-out-6001.iad6.amazon.com with ESMTP; 12 Apr 2021 06:42:07 +0000 Received: from EX13D19EUA003.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan3.iad.amazon.com [10.40.163.38]) by email-inbound-relay-1e-27fb8269.us-east-1.amazon.com (Postfix) with ESMTPS id 141A6A1914; Mon, 12 Apr 2021 06:42:01 +0000 (UTC) Received: from EX13MTAUEA001.ant.amazon.com (10.43.61.82) by EX13D19EUA003.ant.amazon.com (10.43.165.175) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 12 Apr 2021 06:42:00 +0000 Received: from 8c85908914bf.ant.amazon.com.com (10.1.213.33) by mail-relay.amazon.com (10.43.61.243) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Mon, 12 Apr 2021 06:41:57 +0000 From: Gal Pressman To: Jason Gunthorpe , Doug Ledford CC: Yossi Leybovich , , Alexander Matushevsky , Gal Pressman , Jason Gunthorpe , Peter Xu , Andrew Morton , Mike Kravetz Subject: [PATCH for-next v3] RDMA/nldev: Add copy-on-fork attribute to get sys command Date: Mon, 12 Apr 2021 09:41:50 +0300 Message-ID: <20210412064150.40064-1-galpress@amazon.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org The new attribute indicates that the kernel copies DMA pages on fork, hence libibverbs' fork support through madvise and MADV_DONTFORK is not needed. The introduced attribute is always reported as supported since the kernel has the patch that added the copy-on-fork behavior. This allows the userspace library to identify older vs newer kernel versions. Extra care should be taken when backporting this patch as it relies on the fact that the copy-on-fork patch is merged, hence no check for support is added. Don't backport this patch unless you also have the following series: 70e806e4e645 ("mm: Do early cow for pinned pages during fork() for ptes") and 4eae4efa2c29 ("hugetlb: do early cow when page pinned on src mm"). Fixes: 70e806e4e645 ("mm: Do early cow for pinned pages during fork() for ptes") Fixes: 4eae4efa2c29 ("hugetlb: do early cow when page pinned on src mm") Signed-off-by: Gal Pressman Reviewed-by: Leon Romanovsky --- PR was sent: https://github.com/linux-rdma/rdma-core/pull/975 Changelog - v2->v3: https://lore.kernel.org/linux-rdma/21317d2c-9a8e-0dd7-3678-d2933c5053c4@amazon.com/ * Remove check if copy-on-fork attribute was provided from nldev_set_sys_set_doit() v1->v2: https://lore.kernel.org/linux-rdma/20210405114722.98904-1-galpress@amazon.com/ * Remove nla_put_u8() return value check * Add commit hashes to commit message and code comment --- drivers/infiniband/core/nldev.c | 11 +++++++++++ include/uapi/rdma/rdma_netlink.h | 2 ++ 2 files changed, 13 insertions(+) diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c index b8dc002a2478..4889e06a581a 100644 --- a/drivers/infiniband/core/nldev.c +++ b/drivers/infiniband/core/nldev.c @@ -146,6 +146,7 @@ static const struct nla_policy nldev_policy[RDMA_NLDEV_ATTR_MAX] = { [RDMA_NLDEV_ATTR_UVERBS_DRIVER_ID] = { .type = NLA_U32 }, [RDMA_NLDEV_NET_NS_FD] = { .type = NLA_U32 }, [RDMA_NLDEV_SYS_ATTR_NETNS_MODE] = { .type = NLA_U8 }, + [RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK] = { .type = NLA_U8 }, }; static int put_driver_name_print_type(struct sk_buff *msg, const char *name, @@ -1697,6 +1698,16 @@ static int nldev_sys_get_doit(struct sk_buff *skb, struct nlmsghdr *nlh, nlmsg_free(msg); return err; } + + /* + * Copy-on-fork is supported. + * See commits: + * 70e806e4e645 ("mm: Do early cow for pinned pages during fork() for ptes") + * 4eae4efa2c29 ("hugetlb: do early cow when page pinned on src mm") + * for more details. Don't backport this without them. + */ + nla_put_u8(msg, RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK, 1); + nlmsg_end(msg, nlh); return rdma_nl_unicast(sock_net(skb->sk), msg, NETLINK_CB(skb).portid); } diff --git a/include/uapi/rdma/rdma_netlink.h b/include/uapi/rdma/rdma_netlink.h index d2f5b8396243..342c9db5b3c1 100644 --- a/include/uapi/rdma/rdma_netlink.h +++ b/include/uapi/rdma/rdma_netlink.h @@ -533,6 +533,8 @@ enum rdma_nldev_attr { RDMA_NLDEV_ATTR_RES_RAW, /* binary */ + RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK, /* u8 */ + /* * Always the end */