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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B6D46C433EF for ; Mon, 14 Feb 2022 17:42:39 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4JyBPn6dY3z3cVp for ; Tue, 15 Feb 2022 04:42:37 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=ZrqrOMlG; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=ZrqrOMlG; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=redhat.com (client-ip=170.10.129.124; helo=us-smtp-delivery-124.mimecast.com; envelope-from=david@redhat.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=ZrqrOMlG; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=ZrqrOMlG; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4JyBP51flNz3bYq for ; Tue, 15 Feb 2022 04:41:58 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644860514; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=cosw6xv3oQ315iRMA4qLGgG8Dk1NQk9XlhixQZy/TZU=; b=ZrqrOMlGHDval7FWSNNDyohQGNsNzV3JpK+Brl9AWRkguJZKfTA5dkAOEHGfSRdKrTV/+U MED7+8fgJiwYTk7SW1/zWKWkDtdNNUmIJ2cH/iez6K6utcry4W9tq8KwrwiUJAQtBuAMWl GBMjummDUfhkv0G+qCNA9od7HwgCAfY= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644860514; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=cosw6xv3oQ315iRMA4qLGgG8Dk1NQk9XlhixQZy/TZU=; b=ZrqrOMlGHDval7FWSNNDyohQGNsNzV3JpK+Brl9AWRkguJZKfTA5dkAOEHGfSRdKrTV/+U MED7+8fgJiwYTk7SW1/zWKWkDtdNNUmIJ2cH/iez6K6utcry4W9tq8KwrwiUJAQtBuAMWl GBMjummDUfhkv0G+qCNA9od7HwgCAfY= 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-447-a7Zmw9YHM-GC7OCHCJrwmQ-1; Mon, 14 Feb 2022 12:41:50 -0500 X-MC-Unique: a7Zmw9YHM-GC7OCHCJrwmQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A500C1853024; Mon, 14 Feb 2022 17:41:46 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.194.147]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0F5A17DE56; Mon, 14 Feb 2022 17:41:33 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Subject: [PATCH v1 0/2] mm: enforce pageblock_order < MAX_ORDER Date: Mon, 14 Feb 2022 18:41:30 +0100 Message-Id: <20220214174132.219303-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, David Hildenbrand , Aneesh Kumar K V , "Michael S. Tsirkin" , Robin Murphy , virtualization@lists.linux-foundation.org, linux-mm@kvack.org, Minchan Kim , iommu@lists.linux-foundation.org, Rob Herring , Paul Mackerras , Zi Yan , Andrew Morton , Frank Rowand , Christoph Hellwig , Vlastimil Babka , Marek Szyprowski Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Having pageblock_order >= MAX_ORDER seems to be able to happen in corner cases and some parts of the kernel are not prepared for it. For example, Aneesh has shown [1] that such kernels can be compiled on ppc64 with 64k base pages by setting FORCE_MAX_ZONEORDER=8, which will run into a WARN_ON_ONCE(order >= MAX_ORDER) in comapction code right during boot. We can get pageblock_order >= MAX_ORDER when the default hugetlb size is bigger than the maximum allocation granularity of the buddy, in which case we are no longer talking about huge pages but instead gigantic pages. Having pageblock_order >= MAX_ORDER can only make alloc_contig_range() of such gigantic pages more likely to succeed. Reliable use of gigantic pages either requires boot time allcoation or CMA, no need to overcomplicate some places in the kernel to optimize for corner cases that are broken in other areas of the kernel. Let's enforce pageblock_order < MAX_ORDER and simplify. Especially patch #1 can be regarded a cleanup before: [PATCH v5 0/6] Use pageblock_order for cma and alloc_contig_range alignment. [2] [1] https://lkml.kernel.org/r/87r189a2ks.fsf@linux.ibm.com [2] https://lkml.kernel.org/r/20220211164135.1803616-1-zi.yan@sent.com Cc: Andrew Morton Cc: Aneesh Kumar K V Cc: Zi Yan Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Rob Herring Cc: Frank Rowand Cc: "Michael S. Tsirkin" Cc: Christoph Hellwig Cc: Marek Szyprowski Cc: Robin Murphy Cc: Minchan Kim Cc: Vlastimil Babka Cc: linuxppc-dev@lists.ozlabs.org Cc: devicetree@vger.kernel.org Cc: virtualization@lists.linux-foundation.org Cc: iommu@lists.linux-foundation.org Cc: linux-mm@kvack.org David Hildenbrand (2): cma: factor out minimum alignment requirement mm: enforce pageblock_order < MAX_ORDER arch/powerpc/include/asm/fadump-internal.h | 5 ---- arch/powerpc/kernel/fadump.c | 2 +- drivers/of/of_reserved_mem.c | 9 ++---- drivers/virtio/virtio_mem.c | 9 ++---- include/linux/cma.h | 8 ++++++ include/linux/pageblock-flags.h | 7 +++-- kernel/dma/contiguous.c | 4 +-- mm/Kconfig | 3 ++ mm/cma.c | 20 ++++---------- mm/page_alloc.c | 32 ++++++---------------- 10 files changed, 37 insertions(+), 62 deletions(-) base-commit: 754e0b0e35608ed5206d6a67a791563c631cec07 -- 2.34.1