On Thu, 2024-04-11 at 22:07 +1200, Barry Song wrote: > On Thu, Apr 11, 2024 at 9:50 PM kernel test robot <lkp@xxxxxxxxx> wrote: > > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable > > head: de14d5f2a9ff2df737a01575ee95bc5a35f5853d > > commit: 37a4ecbf36cbc84bb1aff0f9c81e58261f8826d9 [364/372] mm: add per-order mTHP swpin_refault counter > > config: s390-allnoconfig (https://download.01.org/0day-ci/archive/20240411/202404111716.GLefx4HG-lkp@xxxxxxxxx/config) > > compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project 8b3b4a92adee40483c27f26c478a384cd69c6f05) > > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240411/202404111716.GLefx4HG-lkp@xxxxxxxxx/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@xxxxxxxxx> > > > Closes: https://lore.kernel.org/oe-kbuild-all/202404111716.GLefx4HG-lkp@xxxxxxxxx/ > > > > All errors (new ones prefixed by >>): > > > > > > mm/memory.c:4169:3: error: call to undeclared function 'count_mthp_stat'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] > > 4169 | count_mthp_stat(folio_order(folio), MTHP_STAT_ANON_SWPIN_REFAULT); > > | ^ > > > > mm/memory.c:4169:39: error: use of undeclared identifier 'MTHP_STAT_ANON_SWPIN_REFAULT' > > 4169 | count_mthp_stat(folio_order(folio), MTHP_STAT_ANON_SWPIN_REFAULT); > > | ^ > > 16 warnings and 2 errors generated. > > Hi, > Thanks! SeongJae also reported this issue, and I had a fix here > https://lore.kernel.org/linux-mm/20240411014636.14023-1-21cnbao@xxxxxxxxx/ > > Can you please test it? We tested the patch above and confirmed it fixes the build error in this report. Tested-by: Yujie Liu <yujie.liu@xxxxxxxxx> Thanks > > > > > > vim +/count_mthp_stat +4169 mm/memory.c > > > > 3927 > > 3928 /* > > 3929 * We enter with non-exclusive mmap_lock (to exclude vma changes, > > 3930 * but allow concurrent faults), and pte mapped but not yet locked. > > 3931 * We return with pte unmapped and unlocked. > > 3932 * > > 3933 * We return with the mmap_lock locked or unlocked in the same cases > > 3934 * as does filemap_fault(). > > 3935 */ > > 3936 vm_fault_t do_swap_page(struct vm_fault *vmf) > > 3937 { > > 3938 struct vm_area_struct *vma = vmf->vma; > > 3939 struct folio *swapcache, *folio = NULL; > > 3940 struct page *page; > > 3941 struct swap_info_struct *si = NULL; > > 3942 rmap_t rmap_flags = RMAP_NONE; > > 3943 bool need_clear_cache = false; > > 3944 bool exclusive = false; > > 3945 swp_entry_t entry; > > 3946 pte_t pte; > > 3947 vm_fault_t ret = 0; > > 3948 void *shadow = NULL; > > 3949 int nr_pages = 1; > > 3950 unsigned long start_address = vmf->address; > > 3951 pte_t *start_pte = vmf->pte; > > 3952 bool any_swap_shared = false; > > 3953 > > 3954 if (!pte_unmap_same(vmf)) > > 3955 goto out; > > 3956 > > 3957 entry = pte_to_swp_entry(vmf->orig_pte); > > 3958 if (unlikely(non_swap_entry(entry))) { > > 3959 if (is_migration_entry(entry)) { > > 3960 migration_entry_wait(vma->vm_mm, vmf->pmd, > > 3961 vmf->address); > > 3962 } else if (is_device_exclusive_entry(entry)) { > > 3963 vmf->page = pfn_swap_entry_to_page(entry); > > 3964 ret = remove_device_exclusive_entry(vmf); > > 3965 } else if (is_device_private_entry(entry)) { > > 3966 if (vmf->flags & FAULT_FLAG_VMA_LOCK) { > > 3967 /* > > 3968 * migrate_to_ram is not yet ready to operate > > 3969 * under VMA lock. > > 3970 */ > > 3971 vma_end_read(vma); > > 3972 ret = VM_FAULT_RETRY; > > 3973 goto out; > > 3974 } > > 3975 > > 3976 vmf->page = pfn_swap_entry_to_page(entry); > > 3977 vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, > > 3978 vmf->address, &vmf->ptl); > > 3979 if (unlikely(!vmf->pte || > > 3980 !pte_same(ptep_get(vmf->pte), > > 3981 vmf->orig_pte))) > > 3982 goto unlock; > > 3983 > > 3984 /* > > 3985 * Get a page reference while we know the page can't be > > 3986 * freed. > > 3987 */ > > 3988 get_page(vmf->page); > > 3989 pte_unmap_unlock(vmf->pte, vmf->ptl); > > 3990 ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); > > 3991 put_page(vmf->page); > > 3992 } else if (is_hwpoison_entry(entry)) { > > 3993 ret = VM_FAULT_HWPOISON; > > 3994 } else if (is_pte_marker_entry(entry)) { > > 3995 ret = handle_pte_marker(vmf); > > 3996 } else { > > 3997 print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); > > 3998 ret = VM_FAULT_SIGBUS; > > 3999 } > > 4000 goto out; > > 4001 } > > 4002 > > 4003 /* Prevent swapoff from happening to us. */ > > 4004 si = get_swap_device(entry); > > 4005 if (unlikely(!si)) > > 4006 goto out; > > 4007 > > 4008 folio = swap_cache_get_folio(entry, vma, vmf->address); > > 4009 if (folio) > > 4010 page = folio_file_page(folio, swp_offset(entry)); > > 4011 swapcache = folio; > > 4012 > > 4013 if (!folio) { > > 4014 if (data_race(si->flags & SWP_SYNCHRONOUS_IO) && > > 4015 __swap_count(entry) == 1) { > > 4016 /* > > 4017 * Prevent parallel swapin from proceeding with > > 4018 * the cache flag. Otherwise, another thread may > > 4019 * finish swapin first, free the entry, and swapout > > 4020 * reusing the same entry. It's undetectable as > > 4021 * pte_same() returns true due to entry reuse. > > 4022 */ > > 4023 if (swapcache_prepare(entry)) { > > 4024 /* Relax a bit to prevent rapid repeated page faults */ > > 4025 schedule_timeout_uninterruptible(1); > > 4026 goto out; > > 4027 } > > 4028 need_clear_cache = true; > > 4029 > > 4030 /* skip swapcache */ > > 4031 folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, > > 4032 vma, vmf->address, false); > > 4033 page = &folio->page; > > 4034 if (folio) { > > 4035 __folio_set_locked(folio); > > 4036 __folio_set_swapbacked(folio); > > 4037 > > 4038 if (mem_cgroup_swapin_charge_folio(folio, > > 4039 vma->vm_mm, GFP_KERNEL, > > 4040 entry)) { > > 4041 ret = VM_FAULT_OOM; > > 4042 goto out_page; > > 4043 } > > 4044 mem_cgroup_swapin_uncharge_swap(entry); > > 4045 > > 4046 shadow = get_shadow_from_swap_cache(entry); > > 4047 if (shadow) > > 4048 workingset_refault(folio, shadow); > > 4049 > > 4050 folio_add_lru(folio); > > 4051 > > 4052 /* To provide entry to swap_read_folio() */ > > 4053 folio->swap = entry; > > 4054 swap_read_folio(folio, true, NULL); > > 4055 folio->private = NULL; > > 4056 } > > 4057 } else { > > 4058 page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, > > 4059 vmf); > > 4060 if (page) > > 4061 folio = page_folio(page); > > 4062 swapcache = folio; > > 4063 } > > 4064 > > 4065 if (!folio) { > > 4066 /* > > 4067 * Back out if somebody else faulted in this pte > > 4068 * while we released the pte lock. > > 4069 */ > > 4070 vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, > > 4071 vmf->address, &vmf->ptl); > > 4072 if (likely(vmf->pte && > > 4073 pte_same(ptep_get(vmf->pte), vmf->orig_pte))) > > 4074 ret = VM_FAULT_OOM; > > 4075 goto unlock; > > 4076 } > > 4077 > > 4078 /* Had to read the page from swap area: Major fault */ > > 4079 ret = VM_FAULT_MAJOR; > > 4080 count_vm_event(PGMAJFAULT); > > 4081 count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); > > 4082 } else if (PageHWPoison(page)) { > > 4083 /* > > 4084 * hwpoisoned dirty swapcache pages are kept for killing > > 4085 * owner processes (which may be unknown at hwpoison time) > > 4086 */ > > 4087 ret = VM_FAULT_HWPOISON; > > 4088 goto out_release; > > 4089 } > > 4090 > > 4091 ret |= folio_lock_or_retry(folio, vmf); > > 4092 if (ret & VM_FAULT_RETRY) > > 4093 goto out_release; > > 4094 > > 4095 if (swapcache) { > > 4096 /* > > 4097 * Make sure folio_free_swap() or swapoff did not release the > > 4098 * swapcache from under us. The page pin, and pte_same test > > 4099 * below, are not enough to exclude that. Even if it is still > > 4100 * swapcache, we need to check that the page's swap has not > > 4101 * changed. > > 4102 */ > > 4103 if (unlikely(!folio_test_swapcache(folio) || > > 4104 page_swap_entry(page).val != entry.val)) > > 4105 goto out_page; > > 4106 > > 4107 /* > > 4108 * KSM sometimes has to copy on read faults, for example, if > > 4109 * page->index of !PageKSM() pages would be nonlinear inside the > > 4110 * anon VMA -- PageKSM() is lost on actual swapout. > > 4111 */ > > 4112 folio = ksm_might_need_to_copy(folio, vma, vmf->address); > > 4113 if (unlikely(!folio)) { > > 4114 ret = VM_FAULT_OOM; > > 4115 folio = swapcache; > > 4116 goto out_page; > > 4117 } else if (unlikely(folio == ERR_PTR(-EHWPOISON))) { > > 4118 ret = VM_FAULT_HWPOISON; > > 4119 folio = swapcache; > > 4120 goto out_page; > > 4121 } > > 4122 if (folio != swapcache) > > 4123 page = folio_page(folio, 0); > > 4124 > > 4125 /* > > 4126 * If we want to map a page that's in the swapcache writable, we > > 4127 * have to detect via the refcount if we're really the exclusive > > 4128 * owner. Try removing the extra reference from the local LRU > > 4129 * caches if required. > > 4130 */ > > 4131 if ((vmf->flags & FAULT_FLAG_WRITE) && folio == swapcache && > > 4132 !folio_test_ksm(folio) && !folio_test_lru(folio)) > > 4133 lru_add_drain(); > > 4134 } > > 4135 > > 4136 folio_throttle_swaprate(folio, GFP_KERNEL); > > 4137 > > 4138 /* > > 4139 * Back out if somebody else already faulted in this pte. > > 4140 */ > > 4141 vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, > > 4142 &vmf->ptl); > > 4143 > > 4144 /* We hit large folios in swapcache */ > > 4145 if (start_pte && folio_test_large(folio) && folio_test_swapcache(folio)) { > > 4146 int nr = folio_nr_pages(folio); > > 4147 int idx = folio_page_idx(folio, page); > > 4148 unsigned long folio_start = vmf->address - idx * PAGE_SIZE; > > 4149 unsigned long folio_end = folio_start + nr * PAGE_SIZE; > > 4150 pte_t *folio_ptep; > > 4151 pte_t folio_pte; > > 4152 > > 4153 if (unlikely(folio_start < max(vmf->address & PMD_MASK, vma->vm_start))) > > 4154 goto check_pte; > > 4155 if (unlikely(folio_end > pmd_addr_end(vmf->address, vma->vm_end))) > > 4156 goto check_pte; > > 4157 > > 4158 folio_ptep = vmf->pte - idx; > > 4159 folio_pte = ptep_get(folio_ptep); > > 4160 if (!is_swap_pte(folio_pte) || non_swap_entry(pte_to_swp_entry(folio_pte)) || > > 4161 swap_pte_batch(folio_ptep, nr, folio_pte, &any_swap_shared) != nr) > > 4162 goto check_pte; > > 4163 > > 4164 start_address = folio_start; > > 4165 start_pte = folio_ptep; > > 4166 nr_pages = nr; > > 4167 entry = folio->swap; > > 4168 page = &folio->page; > > > 4169 count_mthp_stat(folio_order(folio), MTHP_STAT_ANON_SWPIN_REFAULT); > > 4170 } > > 4171 > > 4172 check_pte: > > 4173 if (unlikely(!vmf->pte || !pte_same(ptep_get(vmf->pte), vmf->orig_pte))) > > 4174 goto out_nomap; > > 4175 > > 4176 if (unlikely(!folio_test_uptodate(folio))) { > > 4177 ret = VM_FAULT_SIGBUS; > > 4178 goto out_nomap; > > 4179 } > > 4180 > > 4181 /* > > 4182 * PG_anon_exclusive reuses PG_mappedtodisk for anon pages. A swap pte > > 4183 * must never point at an anonymous page in the swapcache that is > > 4184 * PG_anon_exclusive. Sanity check that this holds and especially, that > > 4185 * no filesystem set PG_mappedtodisk on a page in the swapcache. Sanity > > 4186 * check after taking the PT lock and making sure that nobody > > 4187 * concurrently faulted in this page and set PG_anon_exclusive. > > 4188 */ > > 4189 BUG_ON(!folio_test_anon(folio) && folio_test_mappedtodisk(folio)); > > 4190 BUG_ON(folio_test_anon(folio) && PageAnonExclusive(page)); > > 4191 > > 4192 /* > > 4193 * Check under PT lock (to protect against concurrent fork() sharing > > 4194 * the swap entry concurrently) for certainly exclusive pages. > > 4195 */ > > 4196 if (!folio_test_ksm(folio)) { > > 4197 exclusive = pte_swp_exclusive(vmf->orig_pte); > > 4198 if (folio != swapcache) { > > 4199 /* > > 4200 * We have a fresh page that is not exposed to the > > 4201 * swapcache -> certainly exclusive. > > 4202 */ > > 4203 exclusive = true; > > 4204 } else if (exclusive && folio_test_writeback(folio) && > > 4205 data_race(si->flags & SWP_STABLE_WRITES)) { > > 4206 /* > > 4207 * This is tricky: not all swap backends support > > 4208 * concurrent page modifications while under writeback. > > 4209 * > > 4210 * So if we stumble over such a page in the swapcache > > 4211 * we must not set the page exclusive, otherwise we can > > 4212 * map it writable without further checks and modify it > > 4213 * while still under writeback. > > 4214 * > > 4215 * For these problematic swap backends, simply drop the > > 4216 * exclusive marker: this is perfectly fine as we start > > 4217 * writeback only if we fully unmapped the page and > > 4218 * there are no unexpected references on the page after > > 4219 * unmapping succeeded. After fully unmapped, no > > 4220 * further GUP references (FOLL_GET and FOLL_PIN) can > > 4221 * appear, so dropping the exclusive marker and mapping > > 4222 * it only R/O is fine. > > 4223 */ > > 4224 exclusive = false; > > 4225 } > > 4226 > > 4227 /* Reuse the whole large folio iff all entries are exclusive */ > > 4228 if (nr_pages > 1 && any_swap_shared) > > 4229 exclusive = false; > > 4230 } > > 4231 > > 4232 /* > > 4233 * Some architectures may have to restore extra metadata to the page > > 4234 * when reading from swap. This metadata may be indexed by swap entry > > 4235 * so this must be called before swap_free(). > > 4236 */ > > 4237 arch_swap_restore(folio_swap(entry, folio), folio); > > 4238 > > 4239 /* > > 4240 * Remove the swap entry and conditionally try to free up the swapcache. > > 4241 * We're already holding a reference on the page but haven't mapped it > > 4242 * yet. > > 4243 */ > > 4244 swap_free_nr(entry, nr_pages); > > 4245 if (should_try_to_free_swap(folio, vma, vmf->flags)) > > 4246 folio_free_swap(folio); > > 4247 > > 4248 folio_ref_add(folio, nr_pages - 1); > > 4249 add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr_pages); > > 4250 add_mm_counter(vma->vm_mm, MM_SWAPENTS, -nr_pages); > > 4251 > > 4252 pte = mk_pte(page, vma->vm_page_prot); > > 4253 > > 4254 /* > > 4255 * Same logic as in do_wp_page(); however, optimize for pages that are > > 4256 * certainly not shared either because we just allocated them without > > 4257 * exposing them to the swapcache or because the swap entry indicates > > 4258 * exclusivity. > > 4259 */ > > 4260 if (!folio_test_ksm(folio) && > > 4261 (exclusive || (folio_ref_count(folio) == nr_pages && > > 4262 folio_nr_pages(folio) == nr_pages))) { > > 4263 if (vmf->flags & FAULT_FLAG_WRITE) { > > 4264 pte = maybe_mkwrite(pte_mkdirty(pte), vma); > > 4265 vmf->flags &= ~FAULT_FLAG_WRITE; > > 4266 } > > 4267 rmap_flags |= RMAP_EXCLUSIVE; > > 4268 } > > 4269 flush_icache_pages(vma, page, nr_pages); > > 4270 if (pte_swp_soft_dirty(vmf->orig_pte)) > > 4271 pte = pte_mksoft_dirty(pte); > > 4272 if (pte_swp_uffd_wp(vmf->orig_pte)) > > 4273 pte = pte_mkuffd_wp(pte); > > 4274 > > 4275 /* ksm created a completely new copy */ > > 4276 if (unlikely(folio != swapcache && swapcache)) { > > 4277 folio_add_new_anon_rmap(folio, vma, start_address); > > 4278 folio_add_lru_vma(folio, vma); > > 4279 } else { > > 4280 folio_add_anon_rmap_ptes(folio, page, nr_pages, vma, start_address, > > 4281 rmap_flags); > > 4282 } > > 4283 > > 4284 VM_BUG_ON(!folio_test_anon(folio) || > > 4285 (pte_write(pte) && !PageAnonExclusive(page))); > > 4286 set_ptes(vma->vm_mm, start_address, start_pte, pte, nr_pages); > > 4287 vmf->orig_pte = ptep_get(vmf->pte); > > 4288 arch_do_swap_page(vma->vm_mm, vma, start_address, pte, pte); > > 4289 > > 4290 folio_unlock(folio); > > 4291 if (folio != swapcache && swapcache) { > > 4292 /* > > 4293 * Hold the lock to avoid the swap entry to be reused > > 4294 * until we take the PT lock for the pte_same() check > > 4295 * (to avoid false positives from pte_same). For > > 4296 * further safety release the lock after the swap_free > > 4297 * so that the swap count won't change under a > > 4298 * parallel locked swapcache. > > 4299 */ > > 4300 folio_unlock(swapcache); > > 4301 folio_put(swapcache); > > 4302 } > > 4303 > > 4304 if (vmf->flags & FAULT_FLAG_WRITE) { > > 4305 ret |= do_wp_page(vmf); > > 4306 if (ret & VM_FAULT_ERROR) > > 4307 ret &= VM_FAULT_ERROR; > > 4308 goto out; > > 4309 } > > 4310 > > 4311 /* No need to invalidate - it was non-present before */ > > 4312 update_mmu_cache_range(vmf, vma, start_address, start_pte, nr_pages); > > 4313 unlock: > > 4314 if (vmf->pte) > > 4315 pte_unmap_unlock(vmf->pte, vmf->ptl); > > 4316 out: > > 4317 /* Clear the swap cache pin for direct swapin after PTL unlock */ > > 4318 if (need_clear_cache) > > 4319 swapcache_clear(si, entry); > > 4320 if (si) > > 4321 put_swap_device(si); > > 4322 return ret; > > 4323 out_nomap: > > 4324 if (vmf->pte) > > 4325 pte_unmap_unlock(vmf->pte, vmf->ptl); > > 4326 out_page: > > 4327 folio_unlock(folio); > > 4328 out_release: > > 4329 folio_put(folio); > > 4330 if (folio != swapcache && swapcache) { > > 4331 folio_unlock(swapcache); > > 4332 folio_put(swapcache); > > 4333 } > > 4334 if (need_clear_cache) > > 4335 swapcache_clear(si, entry); > > 4336 if (si) > > 4337 put_swap_device(si); > > 4338 return ret; > > 4339 } > > 4340 > > > > -- > > 0-DAY CI Kernel Test Service > > https://github.com/intel/lkp-tests/wiki > > >
