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 1A2E7C433EF for ; Mon, 13 Dec 2021 12:27:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235430AbhLMM1z (ORCPT ); Mon, 13 Dec 2021 07:27:55 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:33498 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234739AbhLMM1x (ORCPT ); Mon, 13 Dec 2021 07:27:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1639398472; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:references:references; bh=cHrrA+xHo6Rnu19yDTpePX6s2NCJW8s33gvJqfm1SZk=; b=O0+UqwSLH3stF/Z4ae8xtMBPsTMVlwzmp6uPrNaOvrcnHW0oO1NAiDMRxWWXTu2Vzx9xlF jMt0i/lgegrp5OrCc+yw0aSlLG9faSZswELP7pdilwYyTyuq7/sg+Ks/60BzuwJNVB6Gdk 3aMBGPsDziL5LXU6NE4hN925Ng+qNCE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-271-05BO810-MsKa1vDUDMOgxA-1; Mon, 13 Dec 2021 07:27:49 -0500 X-MC-Unique: 05BO810-MsKa1vDUDMOgxA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BEF12874981; Mon, 13 Dec 2021 12:27:47 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-12-202.pek2.redhat.com [10.72.12.202]) by smtp.corp.redhat.com (Postfix) with ESMTP id 386E577F29; Mon, 13 Dec 2021 12:27:38 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, hch@lst.de, cl@linux.com, John.p.donnelly@oracle.com, kexec@lists.infradead.org, bhe@redhat.com Subject: [PATCH v3 2/5] dma-pool: allow user to disable atomic pool Date: Mon, 13 Dec 2021 20:27:09 +0800 Message-Id: <20211213122712.23805-3-bhe@redhat.com> In-Reply-To: <20211213122712.23805-1-bhe@redhat.com> References: <20211213122712.23805-1-bhe@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the current code, three atomic memory pools are always created, atomic_pool_kernel|dma|dma32, even though 'coherent_pool=0' is specified in kernel command line. In fact, atomic pool is only necessary when CONFIG_DMA_DIRECT_REMAP=y or mem_encrypt_active=y which are needed on few ARCHes. So change code to allow user to disable atomic pool by specifying 'coherent_pool=0'. Meanwhile, update the relevant document in kernel-parameter.txt. Signed-off-by: Baoquan He --- Documentation/admin-guide/kernel-parameters.txt | 3 ++- kernel/dma/pool.c | 7 +++++-- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index ec4d25e854a8..d7015309614b 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -664,7 +664,8 @@ coherent_pool=nn[KMG] [ARM,KNL] Sets the size of memory pool for coherent, atomic dma - allocations. Otherwise the default size will be scaled + allocations. A value of 0 disables the three atomic + memory pool. Otherwise the default size will be scaled with memory capacity, while clamped between 128K and 1 << (PAGE_SHIFT + MAX_ORDER-1). diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index 5f84e6cdb78e..5a85804b5beb 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -21,7 +21,7 @@ static struct gen_pool *atomic_pool_kernel __ro_after_init; static unsigned long pool_size_kernel; /* Size can be defined by the coherent_pool command line */ -static size_t atomic_pool_size; +static unsigned long atomic_pool_size = -1; /* Dynamic background expansion when the atomic pool is near capacity */ static struct work_struct atomic_pool_work; @@ -188,11 +188,14 @@ static int __init dma_atomic_pool_init(void) { int ret = 0; + if (!atomic_pool_size) + return 0; + /* * If coherent_pool was not used on the command line, default the pool * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1. */ - if (!atomic_pool_size) { + if (atomic_pool_size == -1) { unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K); pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES); atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K); -- 2.17.2