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 X-Spam-Level: X-Spam-Status: No, score=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 05E61C48BDF for ; Thu, 24 Jun 2021 09:29:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D6139613F6 for ; Thu, 24 Jun 2021 09:29:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231972AbhFXJcA (ORCPT ); Thu, 24 Jun 2021 05:32:00 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:58994 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231717AbhFXJb7 (ORCPT ); Thu, 24 Jun 2021 05:31:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624526980; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=eNB6QImZTsEUvPv7cFGlcy7hZAaXO3u/PVt8yIynlso=; b=KK4u/UPheC0vmdyfDQqJXDJUrN9A5CV/uZzYbn2dikMNpW/eH1QjI7Djdp8jgAINuWttKB K/6SPRZYPZvzmiW94EGiDVQyLhRmo8X6DHXkqYY7icP9yBD2EsSW/h57pNYb5pKwHfMdIf IyLBV2owFnysA+Mi+5mxXcmCScg6giU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-90-QAp785duOPGx24QidhDU9w-1; Thu, 24 Jun 2021 05:29:36 -0400 X-MC-Unique: QAp785duOPGx24QidhDU9w-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 35FFE804140; Thu, 24 Jun 2021 09:29:35 +0000 (UTC) Received: from localhost (ovpn-12-142.pek2.redhat.com [10.72.12.142]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DD8D75C1BB; Thu, 24 Jun 2021 09:29:33 +0000 (UTC) Date: Thu, 24 Jun 2021 17:29:30 +0800 From: Baoquan He To: Christoph Hellwig Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, rientjes@google.com, rppt@linux.ibm.com, thomas.lendacky@amd.com, brijesh.singh@amd.com, kexec@lists.infradead.org, iommu@lists.linux-foundation.org, m.szyprowski@samsung.com, robin.murphy@arm.com Subject: Re: [PATCH RFC 0/2] dma-pool: allow user to disable atomic pool Message-ID: <20210624092930.GA802261@MiWiFi-R3L-srv> References: <20210624052010.5676-1-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/24/21 at 08:40am, Christoph Hellwig wrote: > So reduce the amount allocated. But the pool is needed for proper > operation on systems with memory encryption. And please add the right > maintainer or at least mailing list for the code you're touching next > time. Oh, I thoutht it's memory issue only, should have run ./scripts/get_maintainer.pl. sorry. About reducing the amount allocated, it may not help. Because on x86_64, kdump kernel doesn't put any page of memory into buddy allocator of DMA zone. Means it will defenitely OOM for atomic_pool_dma initialization. Wondering in which case or on which device the atomic pool is needed on AMD system with mem encrytion enabled. As we can see, the OOM will happen too in kdump kernel on Intel system, even though it's not necessary. Thanks Baoquan