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 68AA3C4332F for ; Tue, 22 Nov 2022 14:07:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232779AbiKVOH6 (ORCPT ); Tue, 22 Nov 2022 09:07:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233639AbiKVOHa (ORCPT ); Tue, 22 Nov 2022 09:07:30 -0500 Received: from mail-qk1-x72e.google.com (mail-qk1-x72e.google.com [IPv6:2607:f8b0:4864:20::72e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1C56668284 for ; Tue, 22 Nov 2022 06:06:03 -0800 (PST) Received: by mail-qk1-x72e.google.com with SMTP id x21so10294313qkj.0 for ; Tue, 22 Nov 2022 06:06:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=s1NeuMFXBEcn7qVNMEy11cPUBFu3Uh/CN+zAZ2QB0G4=; b=dZOIDxRugRmuhmjKR0OXDlpibQ9g7OzZSTu5TtWGcOnGoVoiY7Y6qEoGp8700t0AFI HM5anMb6kq6IjenIG3WDlwgAROuLDAvmV/eAjxIA0fiKAOc0YnCDSjJZo9OfbltPDDj1 phMQqtegrg16CWpvlnTRlgonoj0lp0g5TTLKnI45brjRkOAcXkilXxToMCp9LDMH7aAg Z39ZdxRDTknFUbZeZ1j+x84S3OT/hsmjfgySDIGJT/ugL4Jtbuo2r0Fyd6pDgr/eDmr0 zsYXV4EQrw8fTnumR9doPHqZQtITNM6gM4BOiU+AAbCWTUhNBM4xg1wwNaZSUx+xmL60 dSlQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=s1NeuMFXBEcn7qVNMEy11cPUBFu3Uh/CN+zAZ2QB0G4=; b=Wnh+iJq9/u7pjRfYrFwEPq0JhdhNHJqA/RBHFBG8ztJATynGvH2WqP60xkxoHJTR9l SRt8DEjUK8FBIpfoMjVqvVXM9IYLg6ovFt7ArwvBFHIfxAZCSyJ1XnuMO0EU2lblRYs0 mTwpyhigi9AkiA7e4z7mSOWHgBO7YEJzsivWiadKE8dnbXHj44a4P3h4metOLleaS7F2 w3vE3u66YIwHyPrEgfnF2iPYeCGQePYZmvSSWlhIayZGcLLx+MNkwyVXMJtSkGb62kQL ZW/jdlVZWeFIeQdHGtTa75OnkQL/L3TcliS9SFg+9y8/gUphm1YBUA6Nkz/qmBh182Rh 9fxQ== X-Gm-Message-State: ANoB5plmTEjjAC1OY0SnRBT67W98caHylJL2yh8TXY9xpbjWgSjJ7IpP fSmuvqSAEpdAMWe0Fu7dHqLwGcuVrMBIHg== X-Google-Smtp-Source: AA0mqf6HCDOAywWAIuL63AjxSbrxhAlphtu/ShJX3uzC1hOdLJRxMyHLgnXYKixywLOcelQ9z6U6kw== X-Received: by 2002:a05:620a:2225:b0:6fa:b73:812e with SMTP id n5-20020a05620a222500b006fa0b73812emr4983634qkh.433.1669125962104; Tue, 22 Nov 2022 06:06:02 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-47-55-122-23.dhcp-dynamic.fibreop.ns.bellaliant.net. [47.55.122.23]) by smtp.gmail.com with ESMTPSA id p5-20020ac84605000000b003a55fe9f352sm8115029qtn.64.2022.11.22.06.06.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Nov 2022 06:06:01 -0800 (PST) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1oxTuS-009jC3-KW; Tue, 22 Nov 2022 10:06:00 -0400 Date: Tue, 22 Nov 2022 10:06:00 -0400 From: Jason Gunthorpe To: Yanjun Zhu Cc: Zhu Yanjun , zyjzyj2000@gmail.com, leon@kernel.org, linux-rdma@vger.kernel.org Subject: Re: [for-next PATCH 1/1] RDMA/rxe: sgt_append from ib_umem_get is not highmem Message-ID: References: <20221120012939.539953-1-yanjun.zhu@intel.com> <6cb433cb-c463-7cd8-ee5e-7e922733744a@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6cb433cb-c463-7cd8-ee5e-7e922733744a@linux.dev> Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Tue, Nov 22, 2022 at 12:07:06PM +0800, Yanjun Zhu wrote: > But can user space access these high memory? From "Understanding the Linux > Kernel", third edition, it seems that it is in kernel space. Yes, "highmem" is effecitvely the ability to have a struct page * that is not mapped into the kernel address space, but is mapped into a userspace process address sspace. Jason