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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1BEBC71155 for ; Tue, 17 Jun 2025 07:12:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2E2206B0089; Tue, 17 Jun 2025 03:12:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2B8F96B008A; Tue, 17 Jun 2025 03:12:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1F62E6B0092; Tue, 17 Jun 2025 03:12:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 146626B0089 for ; Tue, 17 Jun 2025 03:12:05 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id C0858121A2F for ; Tue, 17 Jun 2025 07:12:04 +0000 (UTC) X-FDA: 83564023368.09.72CA806 Received: from out-173.mta0.migadu.com (out-173.mta0.migadu.com [91.218.175.173]) by imf05.hostedemail.com (Postfix) with ESMTP id 1C07F10000B for ; Tue, 17 Jun 2025 07:12:02 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=wo9EzbQL; spf=pass (imf05.hostedemail.com: domain of hao.ge@linux.dev designates 91.218.175.173 as permitted sender) smtp.mailfrom=hao.ge@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1750144323; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=iWkqbsRsMPadMowH6GNW9aiYIyRsuY18VyS9juVdeNA=; b=0nQRF1a2CtgKU7ulZF1x1LANJ0a6ZDA8V6s5nWxEi9sXNM6+oGf/S+0exobVLMUXFqZruD 6gry5K0jfIiXNVoUtasS5vbV4g4cBCIdjVzQE5gLM1+khiud+INmiVahufDBgGyhsXg3MZ UGgCq5/FBfEs8OCohuh4yjgZOHkHBig= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1750144323; a=rsa-sha256; cv=none; b=WLos4eK4WTac/WH8L2ruFw6JXlrM20Fm8RWjbVYNvmgtvCS4rCcILXsHxpfzhboKv0AqjF FGW1nB72fiZIA7c1oK4xks/VbVjKwwR2A3XPbm6i5WW+QoaS2JRyp6nn9OEM08RLrYhZ45 L9gz0W6nKdhupVT/QdDS0HGTyEwUVTw= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=wo9EzbQL; spf=pass (imf05.hostedemail.com: domain of hao.ge@linux.dev designates 91.218.175.173 as permitted sender) smtp.mailfrom=hao.ge@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1750144321; 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: in-reply-to:in-reply-to:references:references; bh=iWkqbsRsMPadMowH6GNW9aiYIyRsuY18VyS9juVdeNA=; b=wo9EzbQLBhFL4CX4cZvMKamgUfd/1J2xlDdmC/ZrSs/1GhqKR91N4H0M9O5Xw1rHpgknOE Nibg0+KaxJVEF94R2vJgnrF+ow7XnhK2gV19gvdp9zIE6CKVcryGeFmQ+EMZYuxw+gGrYp x+NE6RM8AqhVHJip7978shEGWj4HyVQ= From: Hao Ge To: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Mike Rapoport , Richard Henderson , Matt Turner , Dennis Zhou , Tejun Heo , Christoph Lameter , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Kent Overstreet Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, linux-s390@vger.kernel.org, Hao Ge , Hao Ge Subject: [PATCH v5 1/1] mm/percpu: Conditionally define _shared_alloc_tag via CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU Date: Tue, 17 Jun 2025 15:10:52 +0800 Message-Id: <7b912b54cdc12a3437edbd50dbadfc45545641b7.1750143986.git.gehao@kylinos.cn> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 1C07F10000B X-Stat-Signature: kdyrkr9oepm4j7f8nmysx6hd8rarq4d9 X-HE-Tag: 1750144322-850909 X-HE-Meta: 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 yKzidT8v HNtVOuIVlSs50jtlDYJLZDduuPaBG6fjV/zrwqlOIqKoDZNMzWrwpm98XfXaFX8rJszMHQf6TbuJMuf+HuyJsjZBKi2zk7ZMuTd+acC5p2UjEavcZt5I/PfFj36JLo26gaEQKqbDMa+cslrt0S/HaWzL6EAH3prxbygiKr5ahoQGRwnRnQE1xKab97I4D/ayOuyor703zsDN5XiSGJn73kIEnAn/7v77w97reg31/kZ4mAqJphzMsvUdJTg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Hao Ge Recently discovered this entry while checking kallsyms on ARM64: ffff800083e509c0 D _shared_alloc_tag If ARCH_NEEDS_WEAK_PER_CPU is not defined(it is only defined for s390 and alpha architectures), there's no need to statically define the percpu variable _shared_alloc_tag. Therefore, we need to implement isolation for this purpose. When building the core kernel code for s390 or alpha architectures, ARCH_NEEDS_WEAK_PER_CPU remains undefined (as it is gated by #if defined(MODULE)). However, when building modules for these architectures, the macro is explicitly defined. Therefore, we remove all instances of ARCH_NEEDS_WEAK_PER_CPU from the code and introduced CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU to replace the relevant logic. We can now conditionally define the perpcu variable _shared_alloc_tag based on CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU. This allows architectures (such as s390/alpha) that require weak definitions for percpu variables in modules to include the definition, while others can omit it via compile-time exclusion. Suggested-by: Suren Baghdasaryan Signed-off-by: Hao Ge --- arch/alpha/Kconfig | 1 + arch/alpha/include/asm/percpu.h | 5 ++--- arch/s390/Kconfig | 1 + arch/s390/include/asm/percpu.h | 5 ++--- include/linux/alloc_tag.h | 6 +++--- include/linux/percpu-defs.h | 7 ++++--- lib/alloc_tag.c | 2 ++ mm/Kconfig | 7 +++++++ 8 files changed, 22 insertions(+), 12 deletions(-) diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig index 109a4cddcd13..80367f2cf821 100644 --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -7,6 +7,7 @@ config ALPHA select ARCH_HAS_DMA_OPS if PCI select ARCH_MIGHT_HAVE_PC_PARPORT select ARCH_MIGHT_HAVE_PC_SERIO + select ARCH_MODULE_NEEDS_WEAK_PER_CPU if SMP select ARCH_NO_PREEMPT select ARCH_NO_SG_CHAIN select ARCH_USE_CMPXCHG_LOCKREF diff --git a/arch/alpha/include/asm/percpu.h b/arch/alpha/include/asm/percpu.h index 6923249f2d49..4383d66341dc 100644 --- a/arch/alpha/include/asm/percpu.h +++ b/arch/alpha/include/asm/percpu.h @@ -9,10 +9,9 @@ * way above 4G. * * Always use weak definitions for percpu variables in modules. + * Therefore, we have enabled CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU + * in the Kconfig. */ -#if defined(MODULE) && defined(CONFIG_SMP) -#define ARCH_NEEDS_WEAK_PER_CPU -#endif #include diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 0c16dc443e2f..b652cb952f31 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -132,6 +132,7 @@ config S390 select ARCH_INLINE_WRITE_UNLOCK_IRQ select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE + select ARCH_MODULE_NEEDS_WEAK_PER_CPU select ARCH_STACKWALK select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_SUPPORTS_DEBUG_PAGEALLOC diff --git a/arch/s390/include/asm/percpu.h b/arch/s390/include/asm/percpu.h index 84f6b8357b45..96af7d964014 100644 --- a/arch/s390/include/asm/percpu.h +++ b/arch/s390/include/asm/percpu.h @@ -16,10 +16,9 @@ * For 64 bit module code, the module may be more than 4G above the * per cpu area, use weak definitions to force the compiler to * generate external references. + * Therefore, we have enabled CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU + * in the Kconfig. */ -#if defined(MODULE) -#define ARCH_NEEDS_WEAK_PER_CPU -#endif /* * We use a compare-and-swap loop since that uses less cpu cycles than diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h index 8f7931eb7d16..9ef2633e2c08 100644 --- a/include/linux/alloc_tag.h +++ b/include/linux/alloc_tag.h @@ -88,7 +88,7 @@ static inline struct alloc_tag *ct_to_alloc_tag(struct codetag *ct) return container_of(ct, struct alloc_tag, ct); } -#ifdef ARCH_NEEDS_WEAK_PER_CPU +#if defined(CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU) && defined(MODULE) /* * When percpu variables are required to be defined as weak, static percpu * variables can't be used inside a function (see comments for DECLARE_PER_CPU_SECTION). @@ -102,7 +102,7 @@ DECLARE_PER_CPU(struct alloc_tag_counters, _shared_alloc_tag); .ct = CODE_TAG_INIT, \ .counters = &_shared_alloc_tag }; -#else /* ARCH_NEEDS_WEAK_PER_CPU */ +#else /* CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU && MODULE */ #ifdef MODULE @@ -123,7 +123,7 @@ DECLARE_PER_CPU(struct alloc_tag_counters, _shared_alloc_tag); #endif /* MODULE */ -#endif /* ARCH_NEEDS_WEAK_PER_CPU */ +#endif /* CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU && MODULE */ DECLARE_STATIC_KEY_MAYBE(CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT, mem_alloc_profiling_key); diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h index 0aeb0e276a3e..5931fcad9a91 100644 --- a/include/linux/percpu-defs.h +++ b/include/linux/percpu-defs.h @@ -63,14 +63,15 @@ * 1. The symbol must be globally unique, even the static ones. * 2. Static percpu variables cannot be defined inside a function. * - * Archs which need weak percpu definitions should define - * ARCH_NEEDS_WEAK_PER_CPU in asm/percpu.h when necessary. + * Archs which need weak percpu definitions should set + * CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU when necessary. * * To ensure that the generic code observes the above two * restrictions, if CONFIG_DEBUG_FORCE_WEAK_PER_CPU is set weak * definition is used for all cases. */ -#if defined(ARCH_NEEDS_WEAK_PER_CPU) || defined(CONFIG_DEBUG_FORCE_WEAK_PER_CPU) +#if defined(CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU) && defined(MODULE) || \ + defined(CONFIG_DEBUG_FORCE_WEAK_PER_CPU) /* * __pcpu_scope_* dummy variable is used to enforce scope. It * receives the static modifier when it's used in front of diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c index c7f602fa7b23..ab0936ebf38e 100644 --- a/lib/alloc_tag.c +++ b/lib/alloc_tag.c @@ -24,8 +24,10 @@ static bool mem_profiling_support; static struct codetag_type *alloc_tag_cttype; +#ifdef CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU DEFINE_PER_CPU(struct alloc_tag_counters, _shared_alloc_tag); EXPORT_SYMBOL(_shared_alloc_tag); +#endif DEFINE_STATIC_KEY_MAYBE(CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT, mem_alloc_profiling_key); diff --git a/mm/Kconfig b/mm/Kconfig index e113f713b493..00514df3eae4 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -929,6 +929,13 @@ config ARCH_SUPPORTS_PUD_PFNMAP def_bool y depends on ARCH_SUPPORTS_HUGE_PFNMAP && HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD +# +# Architectures that always use weak definitions for percpu +# variables in modules should set this. +# +config ARCH_MODULE_NEEDS_WEAK_PER_CPU + bool + # # UP and nommu archs use km based percpu allocator # -- 2.25.1