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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 36CAF40016 X-Stat-Signature: 8hse8756xg5ywkt8xgnebhrz84k8ngio X-Rspam-User: X-HE-Tag: 1756826904-854258 X-HE-Meta: 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 7+uaf2wS 1cdpH4bFItpvayEKZ15FVyP4sFLkkEBB9VB2vMD0bX5NBQgysC/9OSvzaNUx7UQZLgS+DpXCvC/0vSYj1KKR5zmnznk4QgmoorINHrNanEt+15gJUSryHeqnWTqRwJRTO/bq8LfV+q2NQBLiCLngRynSshiyEFYJMJOoHnlXgaOR5WOZOwWrMVVQiTV123f6DA4Zr1OZtrQL+FMY9rrim2dTumDzaeWBLkRS3jbDrko4bAjQIPM4YnHFYwtlRNotpQ7Ksa/NmnIsawtYB12TTjv45NOHLtvvZWL6mXowLdg1FhyfpnruLWbUT5syQNZBWc2kngJlP5QpKa2DFUCKEhlO2LTdCUe+1DDOXHg561yznGLohyGRAHCOkufsmrF/J7RXGMngKf7Y9oDIKTFlitiA8MSXCA/mRN3to14Uy/M/plb9E2vmijulYYBdt0t6YHpLa2+y4LCU6PyOS9APOyv9/Ii6YS+okj5tr4E0X5XoPq6I= 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: [...] >> @@ -390,67 +390,88 @@ static void split_pmd_thp_to_order(int order) >> static void split_pte_mapped_thp(void) >> { >> - char *one_page, *pte_mapped, *pte_mapped2; >> - size_t len = 4 * pmd_pagesize; >> - uint64_t thp_size; >> + const size_t nr_thps = 4; >> + const size_t thp_area_size = nr_thps * pmd_pagesize; >> + const size_t page_area_size = nr_thps * pagesize; >> + char *thp_area, *page_area = NULL, *tmp; >> size_t i; >> - one_page = mmap((void *)(1UL << 30), len, PROT_READ | PROT_WRITE, >> + thp_area = mmap((void *)(1UL << 30), thp_area_size, PROT_READ | PROT_WRITE, >> MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); >> - if (one_page == MAP_FAILED) >> - ksft_exit_fail_msg("Fail to allocate memory: %s\n", strerror(errno)); >> + if (thp_area == MAP_FAILED) { >> + ksft_test_result_fail("Fail to allocate memory: %s\n", strerror(errno)); >> + goto out; > > thp_area mmap failed and out label will try to munmap MAP_FAILED, which is > (void *) -1. munmap will fail with -EINVAL. Indeed, should just be a "return;" > >> + } >> - madvise(one_page, len, MADV_HUGEPAGE); >> + madvise(thp_area, thp_area_size, MADV_HUGEPAGE); >> - for (i = 0; i < len; i++) >> - one_page[i] = (char)i; >> + for (i = 0; i < thp_area_size; i++) >> + thp_area[i] = (char)i; >> - if (!check_huge_anon(one_page, 4, pmd_pagesize)) >> - ksft_exit_fail_msg("No THP is allocated\n"); >> + if (!check_huge_anon(thp_area, nr_thps, pmd_pagesize)) { >> + ksft_test_result_skip("Not all THPs allocated\n"); >> + goto out; >> + } >> - /* remap the first pagesize of first THP */ >> - pte_mapped = mremap(one_page, pagesize, pagesize, MREMAP_MAYMOVE); >> - >> - /* remap the Nth pagesize of Nth THP */ >> - for (i = 1; i < 4; i++) { >> - pte_mapped2 = mremap(one_page + pmd_pagesize * i + pagesize * i, >> - pagesize, pagesize, >> - MREMAP_MAYMOVE|MREMAP_FIXED, >> - pte_mapped + pagesize * i); >> - if (pte_mapped2 == MAP_FAILED) >> - ksft_exit_fail_msg("mremap failed: %s\n", strerror(errno)); >> - } >> - >> - /* smap does not show THPs after mremap, use kpageflags instead */ >> - thp_size = 0; >> - for (i = 0; i < pagesize * 4; i++) >> - if (i % pagesize == 0 && >> - is_backed_by_folio(&pte_mapped[i], pmd_order, pagemap_fd, kpageflags_fd)) >> - thp_size++; >> - >> - if (thp_size != 4) >> - ksft_exit_fail_msg("Some THPs are missing during mremap\n"); >> - >> - /* split all remapped THPs */ >> - write_debugfs(PID_FMT, getpid(), (uint64_t)pte_mapped, >> - (uint64_t)pte_mapped + pagesize * 4, 0); >> - >> - /* smap does not show THPs after mremap, use kpageflags instead */ >> - thp_size = 0; >> - for (i = 0; i < pagesize * 4; i++) { >> - if (pte_mapped[i] != (char)i) >> - ksft_exit_fail_msg("%ld byte corrupted\n", i); >> + /* >> + * To challenge spitting code, we will mremap page[x] of the >> + * thp[x] into a smaller area, and trigger the split from that >> + * smaller area. This will end up replacing the PMD mappings in >> + * the thp_area by PTE mappings first, leaving the THPs unsplit. >> + */ >> + page_area = mmap(NULL, page_area_size, PROT_READ | PROT_WRITE, >> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); >> + if (page_area == MAP_FAILED) { >> + ksft_test_result_fail("Fail to allocate memory: %s\n", strerror(errno)); >> + goto out; >> + } >> - if (i % pagesize == 0 && >> - !is_backed_by_folio(&pte_mapped[i], 0, pagemap_fd, kpageflags_fd)) >> - thp_size++; >> + for (i = 0; i < nr_thps; i++) { >> + tmp = mremap(thp_area + pmd_pagesize * i + pagesize * i, >> + pagesize, pagesize, MREMAP_MAYMOVE|MREMAP_FIXED, >> + page_area + pagesize * i); >> + if (tmp != MAP_FAILED) >> + continue; >> + ksft_test_result_fail("mremap failed: %s\n", strerror(errno)); >> + goto out; >> + } >> + >> + /* >> + * Verify that our THPs were not split yet. Note that >> + * check_huge_anon() cannot be used as it checks for PMD mappings. >> + */ >> + for (i = 0; i < nr_thps; i++) { >> + if (is_backed_by_folio(page_area + i * pagesize, pmd_order, >> + pagemap_fd, kpageflags_fd)) >> + continue; >> + ksft_test_result_fail("THP %zu missing after mremap\n", i); >> + goto out; >> } >> - if (thp_size) >> - ksft_exit_fail_msg("Still %ld THPs not split\n", thp_size); >> + /* Split all THPs through the remapped pages. */ >> + write_debugfs(PID_FMT, getpid(), (uint64_t)page_area, >> + (uint64_t)page_area + page_area_size, 0); >> + >> + /* Corruption during mremap or split? */ >> + for (i = 0; i < page_area_size; i++) { >> + if (page_area[i] == (char)i) >> + continue; >> + ksft_test_result_fail("%zu byte corrupted\n", i); >> + goto out; >> + } >> + >> + /* Split failed? */ >> + for (i = 0; i < nr_thps; i++) { >> + if (is_backed_by_folio(&page_area[i], 0, pagemap_fd, kpageflags_fd)) > > page_area + i * pagesize, like Wei pointed out in another email. > >> + continue; >> + ksft_test_result_fail("THP %zu not split\n", i); >> + } >> ksft_test_result_pass("Split PTE-mapped huge pages successful\n"); >> - munmap(one_page, len); >> +out: >> + munmap(thp_area, thp_area_size); >> + if (page_area) >> + munmap(page_area, page_area_size); >> } >> static void split_file_backed_thp(int order) >> -- >> 2.50.1 > > Otherwise, LGTM. With all the changes in this email and other email, > feel free to add Reviewed-by: Zi Yan when you send it > out formally. Thanks! I'm currently chasing why I keep getting temporary Bail out! Some THPs are missing during mremap Already on the old test. Something doesn't work quite right as it seems. -- Cheers David / dhildenb