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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT 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 F1BC5C28CC5 for ; Wed, 5 Jun 2019 21:21:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AF89D20866 for ; Wed, 5 Jun 2019 21:21:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="uI2GOFin" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726717AbfFEVVM (ORCPT ); Wed, 5 Jun 2019 17:21:12 -0400 Received: from mail-ed1-f65.google.com ([209.85.208.65]:46150 "EHLO mail-ed1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726502AbfFEVVL (ORCPT ); Wed, 5 Jun 2019 17:21:11 -0400 Received: by mail-ed1-f65.google.com with SMTP id h10so7709623edi.13; Wed, 05 Jun 2019 14:21:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:reply-to:references:mime-version :content-disposition:in-reply-to:user-agent; bh=DbESKGjaSdEzS+8K4ZZpYJHwCVMJbIIgpVyCBcGmoDA=; b=uI2GOFinAV8sZvL+69rPUYkiOvfq/P6RaIvMP/TCLE7Eigu+OsAMxrlQ7M56dpfeaB KXnPuGlaLKfjVW4OK022oY9x2O84uuKCnTuTJ2Hy/rU4g60rDzrdLH9+Tx5dD+CSiY7P MZd6Gt4WuEMmALvkc+6OxkvqFlyqE8pj0B+RKWqsERmaO6rCiyUFNdAQJaK+bn+j6ZDo 3+Ozb7/fHxX66bj8rSxIxrArPzuRzb+SpAu32sfxsWnMui2GD+nbp3sZ5ByAMfIb0inB TyCDQNWvPlw0yG17KhNWZpYS35pRM3rqQaLlQ7Rzw4ggssD4+ZfqKxNNHceKsI3nMqCT +Ubw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:reply-to :references:mime-version:content-disposition:in-reply-to:user-agent; bh=DbESKGjaSdEzS+8K4ZZpYJHwCVMJbIIgpVyCBcGmoDA=; b=FzvGTNKn5LE6VkjWKZLPUGq6II1chgo7rlCQah2lnt6j1Sef/fD06PtaEBLUEg/68u Llm1DAlbL0agPfzbYF8KjuDkY8DKBpz95zF2qjvMz3cErDte1pdCy2hhjnWTb6V4v0P3 QIcDoLkUsYnuBjPaly6Cv1bO40rKmyp7gzSa7paJJmVBYFHIqblVxGRYa/7/qdq7pPn3 GZm3JPtP+A0fLUzVzNiutRuN+tMgWPN1azZUBmRym7dAvFmUln1jF9WHQTsszPP+4vkT FWGji+6Og8Mvsu2x6/6c83zwLxV9mJJH4X8hFLdl9Q/5kLWjNXOlnrhKFjZdWRc4yfdD pinA== X-Gm-Message-State: APjAAAWK0VvuMcnhFcPA+h2BBY4it2UHg1hrmGYQf4RFb0yfwZghgXhL QVIH4VIKcsOFy1Cwm/GdyOQ8LK3vK04= X-Google-Smtp-Source: APXvYqyuNRjvHNzTb2gEE1mIj1supSxm4qc3GPA7ju0Tg73FF069vkjl4Ke6VX7sPJnRrK6BAE1EDw== X-Received: by 2002:a50:b523:: with SMTP id y32mr38680719edd.209.1559769668613; Wed, 05 Jun 2019 14:21:08 -0700 (PDT) Received: from localhost ([185.92.221.13]) by smtp.gmail.com with ESMTPSA id x19sm3180078edq.9.2019.06.05.14.21.07 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 05 Jun 2019 14:21:07 -0700 (PDT) Date: Wed, 5 Jun 2019 21:21:06 +0000 From: Wei Yang To: David Hildenbrand Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-arm-kernel@lists.infradead.org, akpm@linux-foundation.org, Dan Williams , Wei Yang , Igor Mammedov , Greg Kroah-Hartman , "Rafael J. Wysocki" , Alex Deucher , "David S. Miller" , Mark Brown , Chris Wilson , Oscar Salvador , Jonathan Cameron Subject: Re: [PATCH v3 10/11] mm/memory_hotplug: Make unregister_memory_block_under_nodes() never fail Message-ID: <20190605212106.6folqx2zawbvzzmm@master> Reply-To: Wei Yang References: <20190527111152.16324-1-david@redhat.com> <20190527111152.16324-11-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190527111152.16324-11-david@redhat.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 27, 2019 at 01:11:51PM +0200, David Hildenbrand wrote: >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 Reviewed-by: Wei Yang >--- > 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 -- Wei Yang Help you, Help me