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=-7.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 0791FC43441 for ; Mon, 19 Nov 2018 16:47:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C39C2214DA for ; Mon, 19 Nov 2018 16:47:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="eyBlQ8/i" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C39C2214DA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389101AbeKTDLg (ORCPT ); Mon, 19 Nov 2018 22:11:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:47522 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388196AbeKTDLg (ORCPT ); Mon, 19 Nov 2018 22:11:36 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7CB142145D; Mon, 19 Nov 2018 16:47:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1542646044; bh=n4sBl1VuAd8e/omIZ5nQYGs4R8V9o73AA6sFXxvuvek=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eyBlQ8/iFVcUd1E4VgGQND+yZRCPF2jpNGd0j+/cr4+MOJVhcGeQt7WvrsoRLS1Cb c6az/c6hBp3VicVw3JlPrLge/xliAuZy1AsmMc8b2sU22uN3GX0+pgyv8UlUA2UObU EUx+p3f+Nf5Nqcx+dwm1GPzpwhSZW1Mh4lNtfmSY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Rashmica Gupta , Michael Ellerman , Sasha Levin Subject: [PATCH 4.14 015/124] powerpc/memtrace: Remove memory in chunks Date: Mon, 19 Nov 2018 17:27:49 +0100 Message-Id: <20181119162615.894653973@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181119162612.951907286@linuxfoundation.org> References: <20181119162612.951907286@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Rashmica Gupta [ Upstream commit 3f7daf3d7582dc6628ac40a9045dd1bbd80c5f35 ] When hot-removing memory release_mem_region_adjustable() splits iomem resources if they are not the exact size of the memory being hot-deleted. Adding this memory back to the kernel adds a new resource. Eg a node has memory 0x0 - 0xfffffffff. Hot-removing 1GB from 0xf40000000 results in the single resource 0x0-0xfffffffff being split into two resources: 0x0-0xf3fffffff and 0xf80000000-0xfffffffff. When we hot-add the memory back we now have three resources: 0x0-0xf3fffffff, 0xf40000000-0xf7fffffff, and 0xf80000000-0xfffffffff. This is an issue if we try to remove some memory that overlaps resources. Eg when trying to remove 2GB at address 0xf40000000, release_mem_region_adjustable() fails as it expects the chunk of memory to be within the boundaries of a single resource. We then get the warning: "Unable to release resource" and attempting to use memtrace again gives us this error: "bash: echo: write error: Resource temporarily unavailable" This patch makes memtrace remove memory in chunks that are always the same size from an address that is always equal to end_of_memory - n*size, for some n. So hotremoving and hotadding memory of different sizes will now not attempt to remove memory that spans multiple resources. Signed-off-by: Rashmica Gupta Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/platforms/powernv/memtrace.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) --- a/arch/powerpc/platforms/powernv/memtrace.c +++ b/arch/powerpc/platforms/powernv/memtrace.c @@ -119,17 +119,15 @@ static bool memtrace_offline_pages(u32 n walk_memory_range(start_pfn, end_pfn, (void *)MEM_OFFLINE, change_memblock_state); - lock_device_hotplug(); - remove_memory(nid, start_pfn << PAGE_SHIFT, nr_pages << PAGE_SHIFT); - unlock_device_hotplug(); return true; } static u64 memtrace_alloc_node(u32 nid, u64 size) { - u64 start_pfn, end_pfn, nr_pages; + u64 start_pfn, end_pfn, nr_pages, pfn; u64 base_pfn; + u64 bytes = memory_block_size_bytes(); if (!NODE_DATA(nid) || !node_spanned_pages(nid)) return 0; @@ -142,8 +140,21 @@ static u64 memtrace_alloc_node(u32 nid, end_pfn = round_down(end_pfn - nr_pages, nr_pages); for (base_pfn = end_pfn; base_pfn > start_pfn; base_pfn -= nr_pages) { - if (memtrace_offline_pages(nid, base_pfn, nr_pages) == true) + if (memtrace_offline_pages(nid, base_pfn, nr_pages) == true) { + /* + * Remove memory in memory block size chunks so that + * iomem resources are always split to the same size and + * we never try to remove memory that spans two iomem + * resources. + */ + lock_device_hotplug(); + end_pfn = base_pfn + nr_pages; + for (pfn = base_pfn; pfn < end_pfn; pfn += bytes>> PAGE_SHIFT) { + remove_memory(nid, pfn << PAGE_SHIFT, bytes); + } + unlock_device_hotplug(); return base_pfn << PAGE_SHIFT; + } } return 0;