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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ADFF8C433EF for ; Thu, 14 Oct 2021 08:42:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 875A0610D2 for ; Thu, 14 Oct 2021 08:42:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230132AbhJNIop (ORCPT ); Thu, 14 Oct 2021 04:44:45 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:55686 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230042AbhJNIoo (ORCPT ); Thu, 14 Oct 2021 04:44:44 -0400 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id D3E0621A75; Thu, 14 Oct 2021 08:42:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1634200958; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=CpV2F+cW34agZt5rfrMmvpHTg4zWk28xjJ8r9ZB/HPE=; b=Ano+DfP4Kzw3wR2jq99LrWZlf6sF/9lk0HhIyzfoi5fUhWKa3LWQ/sUwBx1G0cclQoC9fQ 4bT8nXBeChs4LXi7rOJQuWaIM8XBsq5a6A9Ms6xBRrSOy+HZK/637v/bjF45yN5E2U9EaM ae7kwBWrzOZLrairQdaVD5xoIEB2CXE= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 334ACA3B87; Thu, 14 Oct 2021 08:42:37 +0000 (UTC) Date: Thu, 14 Oct 2021 10:42:36 +0200 From: Michal Hocko To: Arnd Bergmann Cc: Andrew Morton , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Vlastimil Babka , Dave Hansen , Stephen Rothwell , Arnd Bergmann , David Hildenbrand , Oscar Salvador , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm/migrate: rework hotplug_memory_notifier() stub Message-ID: References: <20211013144029.2154629-1-arnd@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211013144029.2154629-1-arnd@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 13-10-21 16:39:38, Arnd Bergmann wrote: > From: Arnd Bergmann > > The previous change added a compile time warning for the > CONFIG_MEMORY_HOTPLUG=n case: > > mm/migrate.c:3216:22: error: 'migrate_on_reclaim_callback' defined but not used [-Werror=unused-function] > 3216 | static int __meminit migrate_on_reclaim_callback(struct notifier_block *self, > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ > mm/migrate.c:3197:13: error: 'set_migration_target_nodes' defined but not used [-Werror=unused-function] > 3197 | static void set_migration_target_nodes(void) > | ^~~~~~~~~~~~~~~~~~~~~~~~~~ > > Rework the hotplug_memory_notifier() stub implementation into > an inline function so it always references its argument but > ignores it, leading the compiler to silently drop the hotplug > memory notifier function and further code referenced from it. > > To do this, the #ifdef around those functions need to be removed > as well, but this tends to help with readability and build coverage. > > Fixes: dd3e24b84bc1 ("mm/migrate: add CPU hotplug to demotion #ifdef") This is not a sha1 in the Linus tree. I suspect this comes from linux-next and akpm patch queue. Those sha1s are not stable so it is better to not reference them. Can we fold that into patch directly? > Signed-off-by: Arnd Bergmann The fix looks good to me. Acked-by: Michal Hocko Thanks! > --- > include/linux/memory.h | 5 ++++- > mm/migrate.c | 6 +----- > mm/page_ext.c | 4 +--- > mm/slab.c | 4 ++-- > 4 files changed, 8 insertions(+), 11 deletions(-) > > diff --git a/include/linux/memory.h b/include/linux/memory.h > index a216829df280..95af54f585a1 100644 > --- a/include/linux/memory.h > +++ b/include/linux/memory.h > @@ -125,7 +125,10 @@ static inline int memory_notify(unsigned long val, void *v) > { > return 0; > } > -#define hotplug_memory_notifier(fn, pri) ({ 0; }) > +static inline int hotplug_memory_notifier(notifier_fn_t fn, int pri) > +{ > + return 0; > +} > /* These aren't inline functions due to a GCC bug. */ > #define register_hotmemory_notifier(nb) ({ (void)(nb); 0; }) > #define unregister_hotmemory_notifier(nb) ({ (void)(nb); }) > diff --git a/mm/migrate.c b/mm/migrate.c > index 7769abac8aad..32303d517e10 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -3059,7 +3059,7 @@ void migrate_vma_finalize(struct migrate_vma *migrate) > EXPORT_SYMBOL(migrate_vma_finalize); > #endif /* CONFIG_DEVICE_PRIVATE */ > > -#if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_HOTPLUG_CPU) > +#if defined(CONFIG_HOTPLUG_CPU) > /* Disable reclaim-based migration. */ > static void __disable_all_migrate_targets(void) > { > @@ -3201,7 +3201,6 @@ static void set_migration_target_nodes(void) > put_online_mems(); > } > > -#if defined(CONFIG_MEMORY_HOTPLUG) > /* > * This leaves migrate-on-reclaim transiently disabled between > * the MEM_GOING_OFFLINE and MEM_OFFLINE events. This runs > @@ -3258,9 +3257,7 @@ static int __meminit migrate_on_reclaim_callback(struct notifier_block *self, > > return notifier_from_errno(0); > } > -#endif /* CONFIG_MEMORY_HOTPLUG */ > > -#ifdef CONFIG_HOTPLUG_CPU > /* > * React to hotplug events that might affect the migration targets > * like events that online or offline NUMA nodes. > @@ -3302,4 +3299,3 @@ static int __init migrate_on_reclaim_init(void) > } > late_initcall(migrate_on_reclaim_init); > #endif /* CONFIG_HOTPLUG_CPU */ > -#endif /* CONFIG_MEMORY_HOTPLUG || CONFIG_HOTPLUG_CPU */ > diff --git a/mm/page_ext.c b/mm/page_ext.c > index 106079e67c2e..6242afb24d84 100644 > --- a/mm/page_ext.c > +++ b/mm/page_ext.c > @@ -269,7 +269,7 @@ static int __meminit init_section_page_ext(unsigned long pfn, int nid) > total_usage += table_size; > return 0; > } > -#ifdef CONFIG_MEMORY_HOTPLUG > + > static void free_page_ext(void *addr) > { > if (is_vmalloc_addr(addr)) { > @@ -374,8 +374,6 @@ static int __meminit page_ext_callback(struct notifier_block *self, > return notifier_from_errno(ret); > } > > -#endif > - > void __init page_ext_init(void) > { > unsigned long pfn; > diff --git a/mm/slab.c b/mm/slab.c > index 01775fe0e002..da132a9ae6f8 100644 > --- a/mm/slab.c > +++ b/mm/slab.c > @@ -1095,7 +1095,7 @@ static int slab_offline_cpu(unsigned int cpu) > return 0; > } > > -#if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG) > +#if defined(CONFIG_NUMA) > /* > * Drains freelist for a node on each slab cache, used for memory hot-remove. > * Returns -EBUSY if all objects cannot be drained so that the node is not > @@ -1157,7 +1157,7 @@ static int __meminit slab_memory_callback(struct notifier_block *self, > out: > return notifier_from_errno(ret); > } > -#endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */ > +#endif /* CONFIG_NUMA */ > > /* > * swap the static kmem_cache_node with kmalloced memory > -- > 2.29.2 -- Michal Hocko SUSE Labs