From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 4EF5518E05C for ; Mon, 9 Sep 2024 23:40:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725925245; cv=none; b=eQCotjNmNJrhawovLnhqQStANZ9EU/jRShdNtS8wiODNnv2J/w6IYHxKePGG0DzTOutaimG6kpqq+lV/9mrS2a0zCBa8inXufAzf3XjuQ1ZebUX9aPelaLtaEdYPK8FxV+0o+ppNtDSt6Cj7fJXwlTv8b8gf1plxbgj6mclj6UI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725925245; c=relaxed/simple; bh=Wk5JqegepdK6N8LV35oLG5tNvWmtSXIGYIzteNdXsxg=; h=Date:To:From:Subject:Message-Id; b=QB9SWMsD1fAvNr2kI5YXjqZZ+X4QXJpQfVmc/u3TybS3GU+cvgWJalMA/7fmEMbGcE60B+Ig+1DIiSg02OgSXAvpebhm7erOOKsQGwTp6BmSGFB61uXj5F/hTp+jMh4/vjKQPg8UakbWQ/ZzyAdOTxvYxMzzsor6MsAzrTxxTXY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=WUZsK0a4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="WUZsK0a4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 23103C4CEC5; Mon, 9 Sep 2024 23:40:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1725925245; bh=Wk5JqegepdK6N8LV35oLG5tNvWmtSXIGYIzteNdXsxg=; h=Date:To:From:Subject:From; b=WUZsK0a4Q/s4iRbQYU2jW573ikAtu3Vf2i+AJKKT9xUKIUVUMZqgcIZddPCEvG+Yb 5aHwynseq4ugT50A2Mci8sAPgeC6gwoxDJl4QjXM56LdZdbqDB72dKhCGvk9tupjJj NDycQFpAYaHCaOE8jRM1VWzVqxT6NhannFEeYUyA= Date: Mon, 09 Sep 2024 16:40:44 -0700 To: mm-commits@vger.kernel.org,zhais@google.com,yuzhao@google.com,willy@infradead.org,usamaarif642@gmail.com,szhai2@cs.rochester.edu,shakeel.butt@linux.dev,ryncsn@gmail.com,ryan.roberts@arm.com,rppt@kernel.org,roman.gushchin@linux.dev,riel@surriel.com,npache@redhat.com,hughd@google.com,hannes@cmpxchg.org,david@redhat.com,corbet@lwn.net,cerasuolodomenico@gmail.com,baohua@kernel.org,alexlzhu@fb.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-selftest-to-verify-zero-filled-pages-are-mapped-to-zeropage.patch removed from -mm tree Message-Id: <20240909234045.23103C4CEC5@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm: selftest to verify zero-filled pages are mapped to zeropage has been removed from the -mm tree. Its filename was mm-selftest-to-verify-zero-filled-pages-are-mapped-to-zeropage.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Alexander Zhu Subject: mm: selftest to verify zero-filled pages are mapped to zeropage Date: Fri, 30 Aug 2024 11:03:37 +0100 When a THP is split, any subpage that is zero-filled will be mapped to the shared zeropage, hence saving memory. Add selftest to verify this by allocating zero-filled THP and comparing RssAnon before and after split. Link: https://lkml.kernel.org/r/20240830100438.3623486-4-usamaarif642@gmail.com Signed-off-by: Alexander Zhu Signed-off-by: Usama Arif Acked-by: Rik van Riel Cc: Barry Song Cc: David Hildenbrand Cc: Domenico Cerasuolo Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Kairui Song Cc: Matthew Wilcox Cc: Mike Rapoport Cc: Nico Pache Cc: Roman Gushchin Cc: Ryan Roberts Cc: Shakeel Butt Cc: Shuang Zhai Cc: Yu Zhao Cc: Shuang Zhai Cc: Hugh Dickins Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/split_huge_page_test.c | 71 ++++++++++++ tools/testing/selftests/mm/vm_util.c | 22 +++ tools/testing/selftests/mm/vm_util.h | 1 3 files changed, 94 insertions(+) --- a/tools/testing/selftests/mm/split_huge_page_test.c~mm-selftest-to-verify-zero-filled-pages-are-mapped-to-zeropage +++ a/tools/testing/selftests/mm/split_huge_page_test.c @@ -84,6 +84,76 @@ static void write_debugfs(const char *fm write_file(SPLIT_DEBUGFS, input, ret + 1); } +static char *allocate_zero_filled_hugepage(size_t len) +{ + char *result; + size_t i; + + result = memalign(pmd_pagesize, len); + if (!result) { + printf("Fail to allocate memory\n"); + exit(EXIT_FAILURE); + } + + madvise(result, len, MADV_HUGEPAGE); + + for (i = 0; i < len; i++) + result[i] = (char)0; + + return result; +} + +static void verify_rss_anon_split_huge_page_all_zeroes(char *one_page, int nr_hpages, size_t len) +{ + unsigned long rss_anon_before, rss_anon_after; + size_t i; + + if (!check_huge_anon(one_page, 4, pmd_pagesize)) { + printf("No THP is allocated\n"); + exit(EXIT_FAILURE); + } + + rss_anon_before = rss_anon(); + if (!rss_anon_before) { + printf("No RssAnon is allocated before split\n"); + exit(EXIT_FAILURE); + } + + /* split all THPs */ + write_debugfs(PID_FMT, getpid(), (uint64_t)one_page, + (uint64_t)one_page + len, 0); + + for (i = 0; i < len; i++) + if (one_page[i] != (char)0) { + printf("%ld byte corrupted\n", i); + exit(EXIT_FAILURE); + } + + if (!check_huge_anon(one_page, 0, pmd_pagesize)) { + printf("Still AnonHugePages not split\n"); + exit(EXIT_FAILURE); + } + + rss_anon_after = rss_anon(); + if (rss_anon_after >= rss_anon_before) { + printf("Incorrect RssAnon value. Before: %ld After: %ld\n", + rss_anon_before, rss_anon_after); + exit(EXIT_FAILURE); + } +} + +void split_pmd_zero_pages(void) +{ + char *one_page; + int nr_hpages = 4; + size_t len = nr_hpages * pmd_pagesize; + + one_page = allocate_zero_filled_hugepage(len); + verify_rss_anon_split_huge_page_all_zeroes(one_page, nr_hpages, len); + printf("Split zero filled huge pages successful\n"); + free(one_page); +} + void split_pmd_thp(void) { char *one_page; @@ -431,6 +501,7 @@ int main(int argc, char **argv) fd_size = 2 * pmd_pagesize; + split_pmd_zero_pages(); split_pmd_thp(); split_pte_mapped_thp(); split_file_backed_thp(); --- a/tools/testing/selftests/mm/vm_util.c~mm-selftest-to-verify-zero-filled-pages-are-mapped-to-zeropage +++ a/tools/testing/selftests/mm/vm_util.c @@ -12,6 +12,7 @@ #define PMD_SIZE_FILE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size" #define SMAP_FILE_PATH "/proc/self/smaps" +#define STATUS_FILE_PATH "/proc/self/status" #define MAX_LINE_LENGTH 500 unsigned int __page_size; @@ -171,6 +172,27 @@ uint64_t read_pmd_pagesize(void) return strtoul(buf, NULL, 10); } +unsigned long rss_anon(void) +{ + unsigned long rss_anon = 0; + FILE *fp; + char buffer[MAX_LINE_LENGTH]; + + fp = fopen(STATUS_FILE_PATH, "r"); + if (!fp) + ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__, STATUS_FILE_PATH); + + if (!check_for_pattern(fp, "RssAnon:", buffer, sizeof(buffer))) + goto err_out; + + if (sscanf(buffer, "RssAnon:%10lu kB", &rss_anon) != 1) + ksft_exit_fail_msg("Reading status error\n"); + +err_out: + fclose(fp); + return rss_anon; +} + bool __check_huge(void *addr, char *pattern, int nr_hpages, uint64_t hpage_size) { --- a/tools/testing/selftests/mm/vm_util.h~mm-selftest-to-verify-zero-filled-pages-are-mapped-to-zeropage +++ a/tools/testing/selftests/mm/vm_util.h @@ -39,6 +39,7 @@ unsigned long pagemap_get_pfn(int fd, ch void clear_softdirty(void); bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len); uint64_t read_pmd_pagesize(void); +unsigned long rss_anon(void); bool check_huge_anon(void *addr, int nr_hpages, uint64_t hpage_size); bool check_huge_file(void *addr, int nr_hpages, uint64_t hpage_size); bool check_huge_shmem(void *addr, int nr_hpages, uint64_t hpage_size); _ Patches currently in -mm which might be from alexlzhu@fb.com are