From patchwork Fri Jan 3 08:50:02 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhenhua Huang X-Patchwork-Id: 13925493 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 29B3EE77188 for ; Fri, 3 Jan 2025 11:11:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:Message-ID:Date:Subject:CC:To:From: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=EiTWrdPd+yj2FHOvAvudpCJ9LLU2BCANkcALvO3hnXg=; b=tr3MgAmj/ZEW02U2/3kXt/idYL LxI4St+kX6Tr3NJrFxAYatkIikqDvfZHRK7NvWchLjDvzoO2sI3CrGZLie8S5bAJ9ESR5bfveUNUW YgBZPqlt4nLMEMiJkmXVC/GLhnmShkQMb7KlxRjIX5C5e3bakEJqSioUtHJXnF1oDs2aGWgrCd5mV EnKqZZiXk8gSrlnZHOjFxluLhhxrPNRXiDsu/Dc2wjuN+Gmw+YK+IB+R0VgHa/1dp1RlJgtWARLsj diMjkgRuQDfSrQ5iCYsK3mWPeQ5FFhIjUw8sF5AfATnFgLapCfswlwR6Mja9tiBBo0OkIEWZwU1e0 QW2LilFw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tTfaX-0000000CnI4-1jBS; Fri, 03 Jan 2025 11:11:33 +0000 Received: from mx0b-0031df01.pphosted.com ([205.220.180.131]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tTdOH-0000000CVt1-36Za for linux-arm-kernel@lists.infradead.org; Fri, 03 Jan 2025 08:50:48 +0000 Received: from pps.filterd (m0279871.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 5037FfaZ010711; Fri, 3 Jan 2025 08:50:34 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h= cc:content-transfer-encoding:content-type:date:from:message-id :mime-version:subject:to; s=qcppdkim1; bh=EiTWrdPd+yj2FHOvAvudpC J9LLU2BCANkcALvO3hnXg=; b=AIC0S8b3IAD6JaLfwl7qt0F4ciMStN5A2AfDLR IjfQ7gImt5FfelRLKmmma0ibHhH/C2/QPs3QLVHlCx4WCkOBdRAWbGx1pVOLgkBD uRZg5v40z2+LQ1Oyuoz5NH8IIJF5Pxyajxm3+lhx9K/6OFxbvyEIocycaT/RfLpW dAL8FJdWl9y3x0mLM+UM0bivGBq7+gaeFvWv2dh/4PxzGj4RBy+Fj6CYZkFKKUYB D9FqzueUbqIebYYbfj7A+QkGF4Rzm7SSsXFhOY8pPy5pDF+6gCnnREsT3hTDnDyk 2FH51hxkmb7n6t0+P7tGJ7FjgW40SmN6NdRsHLjQ5rw4aV0Q== Received: from nalasppmta02.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 43xbbp06qy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 03 Jan 2025 08:50:33 +0000 (GMT) Received: from nalasex01a.na.qualcomm.com (nalasex01a.na.qualcomm.com [10.47.209.196]) by NALASPPMTA02.qualcomm.com (8.18.1.2/8.18.1.2) with ESMTPS id 5038oWRY000962 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 3 Jan 2025 08:50:32 GMT Received: from ap-kernel-sh01-lnx.qualcomm.com (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.9; Fri, 3 Jan 2025 00:50:28 -0800 From: Zhenhua Huang To: , CC: , , , , , , , , , , , , , Zhenhua Huang , Subject: [PATCH v3] arm64: mm: Populate vmemmap at the page level for hotplugged sections Date: Fri, 3 Jan 2025 16:50:02 +0800 Message-ID: <20250103085002.27243-1-quic_zhenhuah@quicinc.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nalasex01a.na.qualcomm.com (10.47.209.196) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: pbTVjusVWVeqDA3YjrrNTLMewUxKBtXN X-Proofpoint-GUID: pbTVjusVWVeqDA3YjrrNTLMewUxKBtXN X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.60.29 definitions=2024-09-06_09,2024-09-06_01,2024-09-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 bulkscore=0 phishscore=0 lowpriorityscore=0 malwarescore=0 priorityscore=1501 mlxscore=0 suspectscore=0 impostorscore=0 adultscore=0 mlxlogscore=934 clxscore=1011 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2501030076 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250103_005045_898257_D90805D6 X-CRM114-Status: GOOD ( 21.21 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Commit c1cc1552616d ("arm64: MMU initialisation") optimizes the vmemmap to populate at the PMD section level which was suitable initially since hotplugging granule is always 128M. However, commit ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug") which added 2M hotplugging granule disrupted the arm64 assumptions. Considering the vmemmap_free -> unmap_hotplug_pmd_range path, when pmd_sect() is true, the entire PMD section is cleared, even if there is other effective subsection. For example pagemap1 and pagemap2 are part of a single PMD entry and they are hot-added sequentially. Then pagemap1 is removed, vmemmap_free() will clear the entire PMD entry freeing the struct page metadata for the whole section, even though pagemap2 is still active. To address the issue, we need to prevent PMD/PUD/CONT mappings for both linear and vmemmap for non-boot sections if the size exceeds 2MB (considering sub-section is 2MB). We only permit 2MB blocks in a 4KB page configuration. Cc: stable@vger.kernel.org # v5.4+ Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug") Signed-off-by: Zhenhua Huang --- Hi Catalin and Anshuman, Based on your review comments, I concluded below patch and tested with my setup. I have not folded patchset #2 since this patch seems to be enough for backporting.. Please see if you have further suggestions. arch/arm64/mm/mmu.c | 33 +++++++++++++++++++++++++++++---- 1 file changed, 29 insertions(+), 4 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index e2739b69e11b..2b4d23f01d85 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -42,9 +42,11 @@ #include #include -#define NO_BLOCK_MAPPINGS BIT(0) +#define NO_PMD_BLOCK_MAPPINGS BIT(0) #define NO_CONT_MAPPINGS BIT(1) #define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */ +#define NO_PUD_BLOCK_MAPPINGS BIT(3) /* Hotplug case: do not want block mapping for PUD */ +#define NO_BLOCK_MAPPINGS (NO_PMD_BLOCK_MAPPINGS | NO_PUD_BLOCK_MAPPINGS) u64 kimage_voffset __ro_after_init; EXPORT_SYMBOL(kimage_voffset); @@ -254,7 +256,7 @@ static void init_pmd(pmd_t *pmdp, unsigned long addr, unsigned long end, /* try section mapping first */ if (((addr | next | phys) & ~PMD_MASK) == 0 && - (flags & NO_BLOCK_MAPPINGS) == 0) { + (flags & NO_PMD_BLOCK_MAPPINGS) == 0) { pmd_set_huge(pmdp, phys, prot); /* @@ -356,10 +358,11 @@ static void alloc_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end, /* * For 4K granule only, attempt to put down a 1GB block + * Hotplug case: do not attempt 1GB block */ if (pud_sect_supported() && ((addr | next | phys) & ~PUD_MASK) == 0 && - (flags & NO_BLOCK_MAPPINGS) == 0) { + (flags & NO_PUD_BLOCK_MAPPINGS) == 0) { pud_set_huge(pudp, phys, prot); /* @@ -1175,9 +1178,16 @@ int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node, int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, struct vmem_altmap *altmap) { + unsigned long start_pfn; + struct mem_section *ms; + WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); - if (!IS_ENABLED(CONFIG_ARM64_4K_PAGES)) + start_pfn = page_to_pfn((struct page *)start); + ms = __pfn_to_section(start_pfn); + + /* Hotplugged section not support hugepages */ + if (!IS_ENABLED(CONFIG_ARM64_4K_PAGES) || !early_section(ms)) return vmemmap_populate_basepages(start, end, node, altmap); else return vmemmap_populate_hugepages(start, end, node, altmap); @@ -1339,9 +1349,24 @@ int arch_add_memory(int nid, u64 start, u64 size, struct mhp_params *params) { int ret, flags = NO_EXEC_MAPPINGS; + unsigned long start_pfn = page_to_pfn((struct page *)start); + struct mem_section *ms = __pfn_to_section(start_pfn); VM_BUG_ON(!mhp_range_allowed(start, size, true)); + /* Should not be invoked by early section */ + WARN_ON(early_section(ms)); + + if (IS_ENABLED(CONFIG_ARM64_4K_PAGES)) + /* + * As per subsection granule is 2M, allow PMD block mapping in + * case 4K PAGES. + * Other cases forbid section mapping. + */ + flags |= NO_PUD_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; + else + flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; + if (can_set_direct_map()) flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;