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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 944C7C433F5 for ; Tue, 21 Dec 2021 10:14:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1F8706B007B; Tue, 21 Dec 2021 05:14:34 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1A8126B007D; Tue, 21 Dec 2021 05:14:34 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0BEEA6B007E; Tue, 21 Dec 2021 05:14:34 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0032.hostedemail.com [216.40.44.32]) by kanga.kvack.org (Postfix) with ESMTP id F32856B007B for ; Tue, 21 Dec 2021 05:14:33 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id C19408A9BE for ; Tue, 21 Dec 2021 10:14:33 +0000 (UTC) X-FDA: 78941392026.13.33904D1 Received: from mail-pj1-f50.google.com (mail-pj1-f50.google.com [209.85.216.50]) by imf09.hostedemail.com (Postfix) with ESMTP id A8276140038 for ; Tue, 21 Dec 2021 10:14:28 +0000 (UTC) Received: by mail-pj1-f50.google.com with SMTP id mj19so12042777pjb.3 for ; Tue, 21 Dec 2021 02:14:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:to:from:subject :content-transfer-encoding; bh=cXmktojGSuGs+DutGb7wHKeQNBtivoDJrjUNkLFk1U0=; b=bQz5w4SlfwfRi8xASOupNaAALXgySHs/XPzNKKJL1tUDSXty5HrYnRvUJXtRC/OxAq t0oUFQpWECGi6Qv3EzZjw0qawmfUHINm6ezPUgsbjBBqbMW1AERdrHwoWFJOaVfFCQpM DRpbVBIOJI6Fi7Fvil5QNmXoLDc+OjbRkj8g5079fThRaAxQGRdTOsbEc5SAc8Dck4+n LEB5uKkgzGW5TpxYAJm+9aLBvunJ2U5MfqRScTFNEEL0uujpQcW6BG7H3Y2HcQvDGCHD g4tl/czf8XzzrHT5K7dZ9Ft2lg8x7LVQgknu9OsS2xwzxCNIUEwGQw9/DeOuAGtKayj+ Q9iQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:to:from :subject:content-transfer-encoding; bh=cXmktojGSuGs+DutGb7wHKeQNBtivoDJrjUNkLFk1U0=; b=IP7pBGLaTyJqda+r9vSwb3LsJAI4cwqTqfuhOJg+UCiZf1NZdNqY4roplG5POsBvTw N3Ygul80gaAQE33om82MKhTxSnS9LotXY9wVy7eRlTOJ4IseZ3F95Bt/WdBQQRCjtpjF GjZnIz3Qekz3YZnbgtFisdeMyCLhg3W9TaHLxZr0KAQP/bVPOT3yDtppm5gM0saEG8NI 1S7XGSlK2+oEnbCAR8dtR5/0t4Q4EfHvs4IkfIvyQ+dZleAeV+v64B7kfTBOgZU/Yg8F D50UmCdcIFuEibpsdIu1p/lzfJDoBrr5z4kTJykfMQTz0kbYx1a+fZFXqMZCOHTEMsGu 34mg== X-Gm-Message-State: AOAM533cx2U9oEnAZwEJorKbUA0HZ1N/ySqNGzqh1Ek/yG5eRxSNCli9 9/y63cyOWQhtOsw6CymJKe8dEMXgQtJ8bj7D X-Google-Smtp-Source: ABdhPJzbiiuoRj2K7tPfOy5gBqbdigFCbJkUcsdNhiNJXXXYw90EHJCiKagPFAekPAuqhwwIBKMm3w== X-Received: by 2002:a17:902:8d8a:b0:143:bb4a:d1a with SMTP id v10-20020a1709028d8a00b00143bb4a0d1amr2607374plo.1.1640081671891; Tue, 21 Dec 2021 02:14:31 -0800 (PST) Received: from [30.240.97.243] ([205.204.117.107]) by smtp.gmail.com with ESMTPSA id l13sm15594180pfc.1.2021.12.21.02.14.30 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 21 Dec 2021 02:14:31 -0800 (PST) Message-ID: Date: Tue, 21 Dec 2021 18:14:28 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 To: linux-mm@kvack.org, David Hildenbrand From: Eric Ren Subject: [Question] mm/resource: a mistake to use IORESOURCE_SYSRAM instead of IORESOURCE_SYSTEM_RAM? Content-Type: text/plain; charset=UTF-8; format=flowed X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: A8276140038 X-Stat-Signature: bieomod1ff7hsptft7dysq9p9ewjstjs Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=bQz5w4Sl; spf=pass (imf09.hostedemail.com: domain of renzhengeek@gmail.com designates 209.85.216.50 as permitted sender) smtp.mailfrom=renzhengeek@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-HE-Tag: 1640081668-203723 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.026971, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi David, I feel confused on this piece of code: ``` void release_mem_region_adjustable(resource_size_t start,=20 resource_size_t size) { ... snip /* =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * All memory regions ad= ded from memory-hotplug path have the =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * flag IORESOURCE_SYSTE= M_RAM. If the resource does not have =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * this flag, we know th= at we are dealing with a resource coming =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * from HMM/devm. HMM/de= vm use another mechanism to add/release =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * a resource. This goes= via devm_request_mem_region and =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * devm_release_mem_regi= on. =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * HMM/devm take care to= release their resources when they want, =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * so if we are dealing = with them, let us just back off here. =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 */ =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (!(res->flags & IORESOURCE= _SYSRAM)) { =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 break= ; =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 } ``` The comment says IORESOURCE_SYSTEM_RAM while IORESOURCE_SYSRAM is=20 actually used. Is this a mistake? The reason why I come to read about this is that, I got -EEXIST error fro= m add_memory_driver_managed() when I want to virtio_mem regions sitting on=20 Reserved memory region like this in /proc/iomem: ``` fffc0000-183fffffff : Reserved =C2=A0 100000000-183fffffff : System RAM (virtio_mem) =C2=A0=C2=A0=C2=A0 1820000000-183fffffff : System RAM (virtio_mem) // --= > plugged MB ``` EEXIST error happens after plug -> unplug -> plug testing, because the hot-added region remains after unplug. The hot-added region is under Reserved region. The IORESOURCE_SYSRAM flag check will skips to handle children of the Reserved region. Thanks in advance! Eric