From patchwork Mon Dec 13 12:27:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baoquan He X-Patchwork-Id: 12673837 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 1F62EC433EF for ; Mon, 13 Dec 2021 12:29:26 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3A2116B0075; Mon, 13 Dec 2021 07:28:07 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 351006B0078; Mon, 13 Dec 2021 07:28:07 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 240506B007B; Mon, 13 Dec 2021 07:28:07 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0072.hostedemail.com [216.40.44.72]) by kanga.kvack.org (Postfix) with ESMTP id 168BF6B0075 for ; Mon, 13 Dec 2021 07:28:07 -0500 (EST) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id D549A87CBD for ; Mon, 13 Dec 2021 12:27:56 +0000 (UTC) X-FDA: 78912697752.20.63DA7AB Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf15.hostedemail.com (Postfix) with ESMTP id 1167CA000C for ; Mon, 13 Dec 2021 12:27:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1639398476; 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=GiXBKC4rsXrhnyr9y2gHyHTAuu9t2uz+7DL/EoCgsgE=; b=ee5wUzDpH4c72tpq8eQS7cs3uO+YiwfYcC6wmoin3c3nbNUCzvcVSyrBZOfIVd/+GnuisT fx3jxY5IgMkE6uJh6AHdraaOImwv1kpiQpARcYE7+RsFmAWgYVCB7ATetJ5B57QI7NvKny 4IVeMC59Xk4Uz25E5Od5dsOoDtzfvuk= 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-23-tI6aIu55PAyhn_NMucJ9Cg-1; Mon, 13 Dec 2021 07:27:53 -0500 X-MC-Unique: tI6aIu55PAyhn_NMucJ9Cg-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 5D801874990; Mon, 13 Dec 2021 12:27:51 +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 4D90A78342; Mon, 13 Dec 2021 12:27:48 +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, stable@vger.kernel.org Subject: [PATCH v3 3/5] mm_zone: add function to check if managed dma zone exists Date: Mon, 13 Dec 2021 20:27:10 +0800 Message-Id: <20211213122712.23805-4-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 X-Rspamd-Queue-Id: 1167CA000C Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=ee5wUzDp; spf=none (imf15.hostedemail.com: domain of bhe@redhat.com has no SPF policy when checking 170.10.129.124) smtp.mailfrom=bhe@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam04 X-Stat-Signature: medtuqaiex9xaxd31e85m5fpk91eucfj X-HE-Tag: 1639398472-320757 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: In some places of the current kernel, it assumes that dma zone must have managed pages if CONFIG_ZONE_DMA is enabled. While this is not always true. E.g in kdump kernel of x86_64, only low 1M is presented and locked down at very early stage of boot, so that there's no managed pages at all in DMA zone. This exception will always cause page allocation failure if page is requested from DMA zone. Here add function has_managed_dma() and the relevant helper functions to check if there's DMA zone with managed pages. It will be used in later patches. Fixes: 6f599d84231f ("x86/kdump: Always reserve the low 1M when the crashkernel option is specified") Cc: stable@vger.kernel.org Signed-off-by: Baoquan He Reviewed-by: David Hildenbrand --- v2->v3: Rewrite has_managed_dma() in a simpler and more efficient way which is sugggested by DavidH. include/linux/mmzone.h | 9 +++++++++ mm/page_alloc.c | 15 +++++++++++++++ 2 files changed, 24 insertions(+) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 58e744b78c2c..6e1b726e9adf 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1046,6 +1046,15 @@ static inline int is_highmem_idx(enum zone_type idx) #endif } +#ifdef CONFIG_ZONE_DMA +bool has_managed_dma(void); +#else +static inline bool has_managed_dma(void) +{ + return false; +} +#endif + /** * is_highmem - helper function to quickly check if a struct zone is a * highmem zone or not. This is an attempt to keep references diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c5952749ad40..7c7a0b5de2ff 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -9460,3 +9460,18 @@ bool take_page_off_buddy(struct page *page) return ret; } #endif + +#ifdef CONFIG_ZONE_DMA +bool has_managed_dma(void) +{ + struct pglist_data *pgdat; + + for_each_online_pgdat(pgdat) { + struct zone *zone = &pgdat->node_zones[ZONE_DMA]; + + if (managed_zone(zone)) + return true; + } + return false; +} +#endif /* CONFIG_ZONE_DMA */