* Re: [PATCH v5 07/12] khugepaged: add mTHP support
[not found] <20250428181218.85925-8-npache@redhat.com>
@ 2025-05-07 4:55 ` kernel test robot
0 siblings, 0 replies; only message in thread
From: kernel test robot @ 2025-05-07 4:55 UTC (permalink / raw)
To: Nico Pache; +Cc: llvm, oe-kbuild-all
Hi Nico,
kernel test robot noticed the following build warnings:
[auto build test WARNING on next-20250428]
[cannot apply to akpm-mm/mm-everything trace/for-next lwn/docs-next linus/master v6.15-rc4 v6.15-rc3 v6.15-rc2 v6.15-rc5]
[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/Nico-Pache/khugepaged-rename-hpage_collapse_-to-khugepaged_/20250429-021548
base: next-20250428
patch link: https://lore.kernel.org/r/20250428181218.85925-8-npache%40redhat.com
patch subject: [PATCH v5 07/12] khugepaged: add mTHP support
config: x86_64-buildonly-randconfig-001-20250430 (https://download.01.org/0day-ci/archive/20250507/202505071214.33YoO6WE-lkp@intel.com/config)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250507/202505071214.33YoO6WE-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 <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202505071214.33YoO6WE-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> mm/khugepaged.c:1208:6: warning: variable 'pte' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
1208 | if (result != SCAN_SUCCEED)
| ^~~~~~~~~~~~~~~~~~~~~~
mm/khugepaged.c:1308:6: note: uninitialized use occurs here
1308 | if (pte)
| ^~~
mm/khugepaged.c:1208:2: note: remove the 'if' if its condition is always false
1208 | if (result != SCAN_SUCCEED)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
1209 | goto out_up_write;
| ~~~~~~~~~~~~~~~~~
mm/khugepaged.c:1204:6: warning: variable 'pte' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
1204 | if (result != SCAN_SUCCEED)
| ^~~~~~~~~~~~~~~~~~~~~~
mm/khugepaged.c:1308:6: note: uninitialized use occurs here
1308 | if (pte)
| ^~~
mm/khugepaged.c:1204:2: note: remove the 'if' if its condition is always false
1204 | if (result != SCAN_SUCCEED)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
1205 | goto out_up_write;
| ~~~~~~~~~~~~~~~~~
mm/khugepaged.c:1139:12: note: initialize the variable 'pte' to silence this warning
1139 | pte_t *pte, mthp_pte;
| ^
| = NULL
2 warnings generated.
vim +1208 mm/khugepaged.c
9710a78ab2aed09 Zach O'Keefe 2022-07-06 1131
50ad2f24b3b48c7 Zach O'Keefe 2022-07-06 1132 static int collapse_huge_page(struct mm_struct *mm, unsigned long address,
50ad2f24b3b48c7 Zach O'Keefe 2022-07-06 1133 int referenced, int unmapped,
2e6c970ed974576 Nico Pache 2025-04-28 1134 struct collapse_control *cc, bool *mmap_locked,
2e6c970ed974576 Nico Pache 2025-04-28 1135 u8 order, u16 offset)
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1136 {
5503fbf2b0b80c1 Kirill A. Shutemov 2020-06-03 1137 LIST_HEAD(compound_pagelist);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1138 pmd_t *pmd, _pmd;
d857f1e14edec88 Nico Pache 2025-04-28 1139 pte_t *pte, mthp_pte;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1140 pgtable_t pgtable;
5432726848bb27a Matthew Wilcox (Oracle 2023-12-11 1141) struct folio *folio;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1142 spinlock_t *pmd_ptl, *pte_ptl;
50ad2f24b3b48c7 Zach O'Keefe 2022-07-06 1143 int result = SCAN_FAIL;
c131f751ab1a852 Kirill A. Shutemov 2016-09-19 1144 struct vm_area_struct *vma;
ac46d4f3c43241f Jérôme Glisse 2018-12-28 1145 struct mmu_notifier_range range;
d857f1e14edec88 Nico Pache 2025-04-28 1146 unsigned long _address = address + offset * PAGE_SIZE;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1147
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1148 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1149
988ddb710bb5be2 Kirill A. Shutemov 2016-07-26 1150 /*
c1e8d7c6a7a682e Michel Lespinasse 2020-06-08 1151 * Before allocating the hugepage, release the mmap_lock read lock.
988ddb710bb5be2 Kirill A. Shutemov 2016-07-26 1152 * The allocation can take potentially a long time if it involves
c1e8d7c6a7a682e Michel Lespinasse 2020-06-08 1153 * sync compaction, and we do not need to hold the mmap_lock during
988ddb710bb5be2 Kirill A. Shutemov 2016-07-26 1154 * that. We will recheck the vma after taking it again in write mode.
2e6c970ed974576 Nico Pache 2025-04-28 1155 * If collapsing mTHPs we may have already released the read_lock.
988ddb710bb5be2 Kirill A. Shutemov 2016-07-26 1156 */
2e6c970ed974576 Nico Pache 2025-04-28 1157 if (*mmap_locked) {
d8ed45c5dcd455f Michel Lespinasse 2020-06-08 1158 mmap_read_unlock(mm);
2e6c970ed974576 Nico Pache 2025-04-28 1159 *mmap_locked = false;
2e6c970ed974576 Nico Pache 2025-04-28 1160 }
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1161
d857f1e14edec88 Nico Pache 2025-04-28 1162 result = alloc_charge_folio(&folio, mm, cc, order);
9710a78ab2aed09 Zach O'Keefe 2022-07-06 1163 if (result != SCAN_SUCCEED)
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1164 goto out_nolock;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1165
d8ed45c5dcd455f Michel Lespinasse 2020-06-08 1166 mmap_read_lock(mm);
d857f1e14edec88 Nico Pache 2025-04-28 1167 *mmap_locked = true;
d857f1e14edec88 Nico Pache 2025-04-28 1168 result = hugepage_vma_revalidate(mm, address, true, &vma, cc, order);
50ad2f24b3b48c7 Zach O'Keefe 2022-07-06 1169 if (result != SCAN_SUCCEED) {
d8ed45c5dcd455f Michel Lespinasse 2020-06-08 1170 mmap_read_unlock(mm);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1171 goto out_nolock;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1172 }
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1173
507228044236804 Zach O'Keefe 2022-07-06 1174 result = find_pmd_or_thp_or_none(mm, address, &pmd);
507228044236804 Zach O'Keefe 2022-07-06 1175 if (result != SCAN_SUCCEED) {
d8ed45c5dcd455f Michel Lespinasse 2020-06-08 1176 mmap_read_unlock(mm);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1177 goto out_nolock;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1178 }
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1179
50ad2f24b3b48c7 Zach O'Keefe 2022-07-06 1180 if (unmapped) {
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1181 /*
50ad2f24b3b48c7 Zach O'Keefe 2022-07-06 1182 * __collapse_huge_page_swapin will return with mmap_lock
50ad2f24b3b48c7 Zach O'Keefe 2022-07-06 1183 * released when it fails. So we jump out_nolock directly in
50ad2f24b3b48c7 Zach O'Keefe 2022-07-06 1184 * that case. Continuing to collapse causes inconsistency.
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1185 */
d857f1e14edec88 Nico Pache 2025-04-28 1186 result = __collapse_huge_page_swapin(mm, vma, _address, pmd,
d857f1e14edec88 Nico Pache 2025-04-28 1187 referenced, order);
50ad2f24b3b48c7 Zach O'Keefe 2022-07-06 1188 if (result != SCAN_SUCCEED)
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1189 goto out_nolock;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1190 }
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1191
d8ed45c5dcd455f Michel Lespinasse 2020-06-08 1192 mmap_read_unlock(mm);
d857f1e14edec88 Nico Pache 2025-04-28 1193 *mmap_locked = false;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1194 /*
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1195 * Prevent all access to pagetables with the exception of
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1196 * gup_fast later handled by the ptep_clear_flush and the VM
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1197 * handled by the anon_vma lock + PG_lock.
adef440691bab82 Andrea Arcangeli 2023-12-06 1198 *
adef440691bab82 Andrea Arcangeli 2023-12-06 1199 * UFFDIO_MOVE is prevented to race as well thanks to the
adef440691bab82 Andrea Arcangeli 2023-12-06 1200 * mmap_lock.
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1201 */
d8ed45c5dcd455f Michel Lespinasse 2020-06-08 1202 mmap_write_lock(mm);
d857f1e14edec88 Nico Pache 2025-04-28 1203 result = hugepage_vma_revalidate(mm, address, true, &vma, cc, order);
50ad2f24b3b48c7 Zach O'Keefe 2022-07-06 1204 if (result != SCAN_SUCCEED)
18d24a7cd9d3f35 Miaohe Lin 2021-05-04 1205 goto out_up_write;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1206 /* check if the pmd is still valid */
507228044236804 Zach O'Keefe 2022-07-06 1207 result = check_pmd_still_valid(mm, address, pmd);
507228044236804 Zach O'Keefe 2022-07-06 @1208 if (result != SCAN_SUCCEED)
18d24a7cd9d3f35 Miaohe Lin 2021-05-04 1209 goto out_up_write;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1210
55fd6fccad3172c Suren Baghdasaryan 2023-02-27 1211 vma_start_write(vma);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1212 anon_vma_lock_write(vma->anon_vma);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1213
d857f1e14edec88 Nico Pache 2025-04-28 1214 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, _address,
d857f1e14edec88 Nico Pache 2025-04-28 1215 _address + (PAGE_SIZE << order));
ac46d4f3c43241f Jérôme Glisse 2018-12-28 1216 mmu_notifier_invalidate_range_start(&range);
ec649c9d454ea37 Ville Syrjälä 2019-11-05 1217
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1218 pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */
d857f1e14edec88 Nico Pache 2025-04-28 1219
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1220 /*
70cbc3cc78a997d Yang Shi 2022-09-07 1221 * This removes any huge TLB entry from the CPU so we won't allow
70cbc3cc78a997d Yang Shi 2022-09-07 1222 * huge and small TLB entries for the same virtual address to
70cbc3cc78a997d Yang Shi 2022-09-07 1223 * avoid the risk of CPU bugs in that area.
70cbc3cc78a997d Yang Shi 2022-09-07 1224 *
0ae0b2b32553398 David Hildenbrand 2024-04-02 1225 * Parallel GUP-fast is fine since GUP-fast will back off when
70cbc3cc78a997d Yang Shi 2022-09-07 1226 * it detects PMD is changed.
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1227 */
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1228 _pmd = pmdp_collapse_flush(vma, address, pmd);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1229 spin_unlock(pmd_ptl);
ac46d4f3c43241f Jérôme Glisse 2018-12-28 1230 mmu_notifier_invalidate_range_end(&range);
2ba99c5e0881249 Jann Horn 2022-11-25 1231 tlb_remove_table_sync_one();
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1232
d857f1e14edec88 Nico Pache 2025-04-28 1233 pte = pte_offset_map_lock(mm, &_pmd, _address, &pte_ptl);
895f5ee464cc90a Hugh Dickins 2023-06-08 1234 if (pte) {
d857f1e14edec88 Nico Pache 2025-04-28 1235 result = __collapse_huge_page_isolate(vma, _address, pte, cc,
d857f1e14edec88 Nico Pache 2025-04-28 1236 &compound_pagelist, order);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1237 spin_unlock(pte_ptl);
895f5ee464cc90a Hugh Dickins 2023-06-08 1238 } else {
895f5ee464cc90a Hugh Dickins 2023-06-08 1239 result = SCAN_PMD_NULL;
895f5ee464cc90a Hugh Dickins 2023-06-08 1240 }
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1241
50ad2f24b3b48c7 Zach O'Keefe 2022-07-06 1242 if (unlikely(result != SCAN_SUCCEED)) {
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1243 spin_lock(pmd_ptl);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1244 BUG_ON(!pmd_none(*pmd));
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1245 /*
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1246 * We can only use set_pmd_at when establishing
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1247 * hugepmds and never for establishing regular pmds that
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1248 * points to regular pagetables. Use pmd_populate for that
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1249 */
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1250 pmd_populate(mm, pmd, pmd_pgtable(_pmd));
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1251 spin_unlock(pmd_ptl);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1252 anon_vma_unlock_write(vma->anon_vma);
18d24a7cd9d3f35 Miaohe Lin 2021-05-04 1253 goto out_up_write;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1254 }
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1255
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1256 /*
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1257 * All pages are isolated and locked so anon_vma rmap
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1258 * can't run anymore.
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1259 */
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1260 anon_vma_unlock_write(vma->anon_vma);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1261
8eca68e2cfdf863 Matthew Wilcox (Oracle 2024-04-03 1262) result = __collapse_huge_page_copy(pte, folio, pmd, _pmd,
d857f1e14edec88 Nico Pache 2025-04-28 1263 vma, _address, pte_ptl,
d857f1e14edec88 Nico Pache 2025-04-28 1264 &compound_pagelist, order);
98c76c9f1ef7599 Jiaqi Yan 2023-03-29 1265 if (unlikely(result != SCAN_SUCCEED))
98c76c9f1ef7599 Jiaqi Yan 2023-03-29 1266 goto out_up_write;
98c76c9f1ef7599 Jiaqi Yan 2023-03-29 1267
588d01f918d42d2 Miaohe Lin 2021-05-04 1268 /*
5432726848bb27a Matthew Wilcox (Oracle 2023-12-11 1269) * The smp_wmb() inside __folio_mark_uptodate() ensures the
5432726848bb27a Matthew Wilcox (Oracle 2023-12-11 1270) * copy_huge_page writes become visible before the set_pmd_at()
5432726848bb27a Matthew Wilcox (Oracle 2023-12-11 1271) * write.
588d01f918d42d2 Miaohe Lin 2021-05-04 1272 */
5432726848bb27a Matthew Wilcox (Oracle 2023-12-11 1273) __folio_mark_uptodate(folio);
d857f1e14edec88 Nico Pache 2025-04-28 1274 if (order == HPAGE_PMD_ORDER) {
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1275 pgtable = pmd_pgtable(_pmd);
8c19e28d02d0517 Matthew Wilcox (Oracle 2025-04-02 1276) _pmd = folio_mk_pmd(folio, vma->vm_page_prot);
f55e1014f9e567d Linus Torvalds 2017-11-29 1277 _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1278
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1279 spin_lock(pmd_ptl);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1280 BUG_ON(!pmd_none(*pmd));
d857f1e14edec88 Nico Pache 2025-04-28 1281 folio_add_new_anon_rmap(folio, vma, _address, RMAP_EXCLUSIVE);
5432726848bb27a Matthew Wilcox (Oracle 2023-12-11 1282) folio_add_lru_vma(folio, vma);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1283 pgtable_trans_huge_deposit(mm, pmd, pgtable);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1284 set_pmd_at(mm, address, pmd, _pmd);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1285 update_mmu_cache_pmd(vma, address, pmd);
dafff3f4c850c98 Usama Arif 2024-08-30 1286 deferred_split_folio(folio, false);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1287 spin_unlock(pmd_ptl);
d857f1e14edec88 Nico Pache 2025-04-28 1288 } else { /* mTHP collapse */
d857f1e14edec88 Nico Pache 2025-04-28 1289 mthp_pte = mk_pte(&folio->page, vma->vm_page_prot);
d857f1e14edec88 Nico Pache 2025-04-28 1290 mthp_pte = maybe_mkwrite(pte_mkdirty(mthp_pte), vma);
d857f1e14edec88 Nico Pache 2025-04-28 1291
d857f1e14edec88 Nico Pache 2025-04-28 1292 spin_lock(pmd_ptl);
d857f1e14edec88 Nico Pache 2025-04-28 1293 folio_ref_add(folio, (1 << order) - 1);
d857f1e14edec88 Nico Pache 2025-04-28 1294 folio_add_new_anon_rmap(folio, vma, _address, RMAP_EXCLUSIVE);
d857f1e14edec88 Nico Pache 2025-04-28 1295 folio_add_lru_vma(folio, vma);
d857f1e14edec88 Nico Pache 2025-04-28 1296 set_ptes(vma->vm_mm, _address, pte, mthp_pte, (1 << order));
d857f1e14edec88 Nico Pache 2025-04-28 1297 update_mmu_cache_range(NULL, vma, _address, pte, (1 << order));
d857f1e14edec88 Nico Pache 2025-04-28 1298
d857f1e14edec88 Nico Pache 2025-04-28 1299 smp_wmb(); /* make pte visible before pmd */
d857f1e14edec88 Nico Pache 2025-04-28 1300 pmd_populate(mm, pmd, pmd_pgtable(_pmd));
d857f1e14edec88 Nico Pache 2025-04-28 1301 spin_unlock(pmd_ptl);
d857f1e14edec88 Nico Pache 2025-04-28 1302 }
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1303
0234779276e56fb Matthew Wilcox (Oracle 2024-04-03 1304) folio = NULL;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1305
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1306 result = SCAN_SUCCEED;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1307 out_up_write:
d857f1e14edec88 Nico Pache 2025-04-28 1308 if (pte)
d857f1e14edec88 Nico Pache 2025-04-28 1309 pte_unmap(pte);
d8ed45c5dcd455f Michel Lespinasse 2020-06-08 1310 mmap_write_unlock(mm);
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1311 out_nolock:
2e6c970ed974576 Nico Pache 2025-04-28 1312 *mmap_locked = false;
0234779276e56fb Matthew Wilcox (Oracle 2024-04-03 1313) if (folio)
0234779276e56fb Matthew Wilcox (Oracle 2024-04-03 1314) folio_put(folio);
50ad2f24b3b48c7 Zach O'Keefe 2022-07-06 1315 trace_mm_collapse_huge_page(mm, result == SCAN_SUCCEED, result);
50ad2f24b3b48c7 Zach O'Keefe 2022-07-06 1316 return result;
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1317 }
b46e756f5e47031 Kirill A. Shutemov 2016-07-26 1318
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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