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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 1F07EC04AB3 for ; Mon, 27 May 2019 11:25:09 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9D15F20859 for ; Mon, 27 May 2019 11:25:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9D15F20859 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 45CF4y4vqTzDqLj for ; Mon, 27 May 2019 21:25:06 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=redhat.com (client-ip=209.132.183.28; helo=mx1.redhat.com; envelope-from=david@redhat.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=redhat.com Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (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 45CDq61lwJzDqFD for ; Mon, 27 May 2019 21:13:06 +1000 (AEST) Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 551563082B5F; Mon, 27 May 2019 11:13:04 +0000 (UTC) Received: from t460s.redhat.com (ovpn-117-89.ams2.redhat.com [10.36.117.89]) by smtp.corp.redhat.com (Postfix) with ESMTP id B086919C7F; Mon, 27 May 2019 11:13:00 +0000 (UTC) From: David Hildenbrand To: linux-mm@kvack.org Subject: [PATCH v3 10/11] mm/memory_hotplug: Make unregister_memory_block_under_nodes() never fail Date: Mon, 27 May 2019 13:11:51 +0200 Message-Id: <20190527111152.16324-11-david@redhat.com> In-Reply-To: <20190527111152.16324-1-david@redhat.com> References: <20190527111152.16324-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Mon, 27 May 2019 11:13:04 +0000 (UTC) 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: linux-s390@vger.kernel.org, linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Greg Kroah-Hartman , Mark Brown , David Hildenbrand , linux-kernel@vger.kernel.org, Wei Yang , Alex Deucher , "David S. Miller" , Jonathan Cameron , "Rafael J. Wysocki" , Igor Mammedov , akpm@linux-foundation.org, Chris Wilson , linuxppc-dev@lists.ozlabs.org, Dan Williams , linux-arm-kernel@lists.infradead.org, Oscar Salvador Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" We really don't want anything during memory hotunplug to fail. We always pass a valid memory block device, that check can go. Avoid allocating memory and eventually failing. As we are always called under lock, we can use a static piece of memory. This avoids having to put the structure onto the stack, having to guess about the stack size of callers. Patch inspired by a patch from Oscar Salvador. In the future, there might be no need to iterate over nodes at all. mem->nid should tell us exactly what to remove. Memory block devices with mixed nodes (added during boot) should properly fenced off and never removed. Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Alex Deucher Cc: "David S. Miller" Cc: Mark Brown Cc: Chris Wilson Cc: David Hildenbrand Cc: Oscar Salvador Cc: Andrew Morton Cc: Jonathan Cameron Signed-off-by: David Hildenbrand --- drivers/base/node.c | 18 +++++------------- include/linux/node.h | 5 ++--- 2 files changed, 7 insertions(+), 16 deletions(-) diff --git a/drivers/base/node.c b/drivers/base/node.c index 04fdfa99b8bc..9be88fd05147 100644 --- a/drivers/base/node.c +++ b/drivers/base/node.c @@ -803,20 +803,14 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, void *arg) /* * Unregister memory block device under all nodes that it spans. + * Has to be called with mem_sysfs_mutex held (due to unlinked_nodes). */ -int unregister_memory_block_under_nodes(struct memory_block *mem_blk) +void unregister_memory_block_under_nodes(struct memory_block *mem_blk) { - NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL); unsigned long pfn, sect_start_pfn, sect_end_pfn; + static nodemask_t unlinked_nodes; - if (!mem_blk) { - NODEMASK_FREE(unlinked_nodes); - return -EFAULT; - } - if (!unlinked_nodes) - return -ENOMEM; - nodes_clear(*unlinked_nodes); - + nodes_clear(unlinked_nodes); sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr); sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr); for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) { @@ -827,15 +821,13 @@ int unregister_memory_block_under_nodes(struct memory_block *mem_blk) continue; if (!node_online(nid)) continue; - if (node_test_and_set(nid, *unlinked_nodes)) + if (node_test_and_set(nid, unlinked_nodes)) continue; sysfs_remove_link(&node_devices[nid]->dev.kobj, kobject_name(&mem_blk->dev.kobj)); sysfs_remove_link(&mem_blk->dev.kobj, kobject_name(&node_devices[nid]->dev.kobj)); } - NODEMASK_FREE(unlinked_nodes); - return 0; } int link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn) diff --git a/include/linux/node.h b/include/linux/node.h index 02a29e71b175..548c226966a2 100644 --- a/include/linux/node.h +++ b/include/linux/node.h @@ -139,7 +139,7 @@ extern int register_cpu_under_node(unsigned int cpu, unsigned int nid); extern int unregister_cpu_under_node(unsigned int cpu, unsigned int nid); extern int register_mem_sect_under_node(struct memory_block *mem_blk, void *arg); -extern int unregister_memory_block_under_nodes(struct memory_block *mem_blk); +extern void unregister_memory_block_under_nodes(struct memory_block *mem_blk); extern int register_memory_node_under_compute_node(unsigned int mem_nid, unsigned int cpu_nid, @@ -175,9 +175,8 @@ static inline int register_mem_sect_under_node(struct memory_block *mem_blk, { return 0; } -static inline int unregister_memory_block_under_nodes(struct memory_block *mem_blk) +static inline void unregister_memory_block_under_nodes(struct memory_block *mem_blk) { - return 0; } static inline void register_hugetlbfs_with_node(node_registration_func_t reg, -- 2.20.1