From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 92A842FD1DC; Wed, 7 Jan 2026 09:47:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767779226; cv=none; b=kkmBvsrT04QEL/DJNGHoXjfF5G7ATrSVH/wBJyUNBsLtCo++ygHyerC/ofhFZ3Kfl6KyLruitWLB3meDlGV4Q0+DWV/kLGG4iG0WsUznLGtFWTQjlTG1I/btNYdIv0VX7EFDKYRhCpk+c2OqT1Ym46Qd1YoVRKXCkazrbrOtgKg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767779226; c=relaxed/simple; bh=a83o+wX7r90L4ywH9PsTkkN4tbWjpPaE9B8Y5qgLNgE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rLd97EWEwv92ggPQus95aACnnPPWATtKiSfNFqfC05wLXCxVCKcn1btXxeZ8YkOOQPRDVFM/v/86n7/0Cjq9Bm+tO65rniCkiWFVSTgT9xeF6SOgjKlgrUm+07ek0inswsb/ru7g6mcl9hDvetaflHL3rHS6G+/ncC6WeXhula4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=LpLvpO0F; arc=none smtp.client-ip=198.175.65.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="LpLvpO0F" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1767779225; x=1799315225; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=a83o+wX7r90L4ywH9PsTkkN4tbWjpPaE9B8Y5qgLNgE=; b=LpLvpO0FbMnjCeZG7Y8CiIhwI054s5+GRBtkv4R4Q6N/a/fi/ouXwB2M 1nnwBebep1kb/NgYMjGEqrtO5d12/jfTDK0J0L1C2OMqxkafrqYt9fiW9 nfGz4gBy/G6qIR0Vhqlhkwy8mnMbd3eCU1g/BNrhAsRjbLTMhlB8s60yT lZDRZV5Dv5DqY6Lu0AW+zm+jIrl+m3A37yAEKjaAyuDny59OpGqa5lXTQ reNYRPW0hmFmUdCMY3hhm5oEWDkwPFaDPd/YVspIkSCwPnmmc8IlIAqZZ Shr3o1dEbs4LgYDtqBgXR01Jw/nkQqfcPJybLMoH9gofMIswHhA8Ge/hx A==; X-CSE-ConnectionGUID: 6vH4R3ulRqSl9KGEnhtFHw== X-CSE-MsgGUID: BI+Vy6EnQd+K+MVDz5bI8Q== X-IronPort-AV: E=McAfee;i="6800,10657,11663"; a="69194214" X-IronPort-AV: E=Sophos;i="6.21,207,1763452800"; d="scan'208";a="69194214" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jan 2026 01:47:04 -0800 X-CSE-ConnectionGUID: jZSHIXi8QfuiQFR7GjwoYQ== X-CSE-MsgGUID: tChYKJK2Qp6DUXgcZ++UGg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,207,1763452800"; d="scan'208";a="202899201" Received: from igk-lkp-server01.igk.intel.com (HELO 92b2e8bd97aa) ([10.211.93.152]) by orviesa007.jf.intel.com with ESMTP; 07 Jan 2026 01:46:57 -0800 Received: from kbuild by 92b2e8bd97aa with local (Exim 4.98.2) (envelope-from ) id 1vdQ7y-000000001Xg-3SbX; Wed, 07 Jan 2026 09:46:54 +0000 Date: Wed, 7 Jan 2026 10:46:12 +0100 From: kernel test robot To: Lance Yang , akpm@linux-foundation.org Cc: oe-kbuild-all@lists.linux.dev, david@kernel.org, dave.hansen@intel.com, dave.hansen@linux.intel.com, will@kernel.org, aneesh.kumar@kernel.org, npiggin@gmail.com, peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, arnd@arndb.de, lorenzo.stoakes@oracle.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, shy828301@gmail.com, riel@surriel.com, jannh@google.com, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ioworker0@gmail.com, Lance Yang Subject: Re: [PATCH RESEND v3 2/2] mm: introduce pmdp_collapse_flush_sync() to skip redundant IPI Message-ID: <202601071005.oEsmtf0J-lkp@intel.com> References: <20260106120303.38124-3-lance.yang@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260106120303.38124-3-lance.yang@linux.dev> Hi Lance, kernel test robot noticed the following build errors: [auto build test ERROR on akpm-mm/mm-everything] [also build test ERROR on next-20260107] [cannot apply to tip/x86/core tip/x86/mm arnd-asm-generic/master linus/master v6.19-rc4] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Lance-Yang/mm-tlb-skip-redundant-IPI-when-TLB-flush-already-synchronized/20260106-200505 base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything patch link: https://lore.kernel.org/r/20260106120303.38124-3-lance.yang%40linux.dev patch subject: [PATCH RESEND v3 2/2] mm: introduce pmdp_collapse_flush_sync() to skip redundant IPI config: s390-allnoconfig-bpf (https://download.01.org/0day-ci/archive/20260107/202601071005.oEsmtf0J-lkp@intel.com/config) compiler: s390-linux-gcc (GCC) 15.1.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260107/202601071005.oEsmtf0J-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot | Closes: https://lore.kernel.org/oe-kbuild-all/202601071005.oEsmtf0J-lkp@intel.com/ All errors (new ones prefixed by >>): mm/khugepaged.c: In function 'collapse_huge_page': >> mm/khugepaged.c:1180:16: error: implicit declaration of function 'pmdp_collapse_flush_sync'; did you mean 'pmdp_collapse_flush'? [-Wimplicit-function-declaration] 1180 | _pmd = pmdp_collapse_flush_sync(vma, address, pmd); | ^~~~~~~~~~~~~~~~~~~~~~~~ | pmdp_collapse_flush vim +1180 mm/khugepaged.c 1092 1093 static enum scan_result collapse_huge_page(struct mm_struct *mm, unsigned long address, 1094 int referenced, int unmapped, 1095 struct collapse_control *cc) 1096 { 1097 LIST_HEAD(compound_pagelist); 1098 pmd_t *pmd, _pmd; 1099 pte_t *pte; 1100 pgtable_t pgtable; 1101 struct folio *folio; 1102 spinlock_t *pmd_ptl, *pte_ptl; 1103 enum scan_result result = SCAN_FAIL; 1104 struct vm_area_struct *vma; 1105 struct mmu_notifier_range range; 1106 1107 VM_BUG_ON(address & ~HPAGE_PMD_MASK); 1108 1109 /* 1110 * Before allocating the hugepage, release the mmap_lock read lock. 1111 * The allocation can take potentially a long time if it involves 1112 * sync compaction, and we do not need to hold the mmap_lock during 1113 * that. We will recheck the vma after taking it again in write mode. 1114 */ 1115 mmap_read_unlock(mm); 1116 1117 result = alloc_charge_folio(&folio, mm, cc); 1118 if (result != SCAN_SUCCEED) 1119 goto out_nolock; 1120 1121 mmap_read_lock(mm); 1122 result = hugepage_vma_revalidate(mm, address, true, &vma, cc); 1123 if (result != SCAN_SUCCEED) { 1124 mmap_read_unlock(mm); 1125 goto out_nolock; 1126 } 1127 1128 result = find_pmd_or_thp_or_none(mm, address, &pmd); 1129 if (result != SCAN_SUCCEED) { 1130 mmap_read_unlock(mm); 1131 goto out_nolock; 1132 } 1133 1134 if (unmapped) { 1135 /* 1136 * __collapse_huge_page_swapin will return with mmap_lock 1137 * released when it fails. So we jump out_nolock directly in 1138 * that case. Continuing to collapse causes inconsistency. 1139 */ 1140 result = __collapse_huge_page_swapin(mm, vma, address, pmd, 1141 referenced); 1142 if (result != SCAN_SUCCEED) 1143 goto out_nolock; 1144 } 1145 1146 mmap_read_unlock(mm); 1147 /* 1148 * Prevent all access to pagetables with the exception of 1149 * gup_fast later handled by the ptep_clear_flush and the VM 1150 * handled by the anon_vma lock + PG_lock. 1151 * 1152 * UFFDIO_MOVE is prevented to race as well thanks to the 1153 * mmap_lock. 1154 */ 1155 mmap_write_lock(mm); 1156 result = hugepage_vma_revalidate(mm, address, true, &vma, cc); 1157 if (result != SCAN_SUCCEED) 1158 goto out_up_write; 1159 /* check if the pmd is still valid */ 1160 vma_start_write(vma); 1161 result = check_pmd_still_valid(mm, address, pmd); 1162 if (result != SCAN_SUCCEED) 1163 goto out_up_write; 1164 1165 anon_vma_lock_write(vma->anon_vma); 1166 1167 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, address, 1168 address + HPAGE_PMD_SIZE); 1169 mmu_notifier_invalidate_range_start(&range); 1170 1171 pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */ 1172 /* 1173 * This removes any huge TLB entry from the CPU so we won't allow 1174 * huge and small TLB entries for the same virtual address to 1175 * avoid the risk of CPU bugs in that area. 1176 * 1177 * Parallel GUP-fast is fine since GUP-fast will back off when 1178 * it detects PMD is changed. 1179 */ > 1180 _pmd = pmdp_collapse_flush_sync(vma, address, pmd); 1181 spin_unlock(pmd_ptl); 1182 mmu_notifier_invalidate_range_end(&range); 1183 1184 pte = pte_offset_map_lock(mm, &_pmd, address, &pte_ptl); 1185 if (pte) { 1186 result = __collapse_huge_page_isolate(vma, address, pte, cc, 1187 &compound_pagelist); 1188 spin_unlock(pte_ptl); 1189 } else { 1190 result = SCAN_NO_PTE_TABLE; 1191 } 1192 1193 if (unlikely(result != SCAN_SUCCEED)) { 1194 if (pte) 1195 pte_unmap(pte); 1196 spin_lock(pmd_ptl); 1197 BUG_ON(!pmd_none(*pmd)); 1198 /* 1199 * We can only use set_pmd_at when establishing 1200 * hugepmds and never for establishing regular pmds that 1201 * points to regular pagetables. Use pmd_populate for that 1202 */ 1203 pmd_populate(mm, pmd, pmd_pgtable(_pmd)); 1204 spin_unlock(pmd_ptl); 1205 anon_vma_unlock_write(vma->anon_vma); 1206 goto out_up_write; 1207 } 1208 1209 /* 1210 * All pages are isolated and locked so anon_vma rmap 1211 * can't run anymore. 1212 */ 1213 anon_vma_unlock_write(vma->anon_vma); 1214 1215 result = __collapse_huge_page_copy(pte, folio, pmd, _pmd, 1216 vma, address, pte_ptl, 1217 &compound_pagelist); 1218 pte_unmap(pte); 1219 if (unlikely(result != SCAN_SUCCEED)) 1220 goto out_up_write; 1221 1222 /* 1223 * The smp_wmb() inside __folio_mark_uptodate() ensures the 1224 * copy_huge_page writes become visible before the set_pmd_at() 1225 * write. 1226 */ 1227 __folio_mark_uptodate(folio); 1228 pgtable = pmd_pgtable(_pmd); 1229 1230 spin_lock(pmd_ptl); 1231 BUG_ON(!pmd_none(*pmd)); 1232 pgtable_trans_huge_deposit(mm, pmd, pgtable); 1233 map_anon_folio_pmd_nopf(folio, pmd, vma, address); 1234 spin_unlock(pmd_ptl); 1235 1236 folio = NULL; 1237 1238 result = SCAN_SUCCEED; 1239 out_up_write: 1240 mmap_write_unlock(mm); 1241 out_nolock: 1242 if (folio) 1243 folio_put(folio); 1244 trace_mm_collapse_huge_page(mm, result == SCAN_SUCCEED, result); 1245 return result; 1246 } 1247 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki