From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Wang Date: Tue, 29 Mar 2016 17:55:44 +0800 Subject: [LTP] [PATCH V2] madvice: new case for madvise(WILLNEED) Message-ID: <1459245344-5983-1-git-send-email-liwang@redhat.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ltp@lists.linux.it Page fault occurs in spite that madvise(WILLNEED) system call is called to prefetch the page. This issue is reproduced by running a program which sequentially accesses to a shared memory and calls madvise(WILLNEED) to the next page on a page fault. Fixed by commit: 55231e5c898 mm: madvise: fix MADV_WILLNEED on shmem swapouts Signed-off-by: Li Wang --- Notes: V1 --> V2 * set the TST_TOTAL = 3, run with '-i 100' can work * declare the addr array as char *dst[100] * create sysinfo struct sys_buf on the stack in setup() * use mmap() with 'MAP_SHARED | MAP_ANONYMOUS' instead shmat() * take use of the assigment-supression operator '*' of fscanf * remove fflush(stdout), free_shm(), cleanup() runtest/syscalls | 1 + testcases/kernel/syscalls/.gitignore | 1 + testcases/kernel/syscalls/madvise/madvise06.c | 172 ++++++++++++++++++++++++++ 3 files changed, 174 insertions(+) create mode 100644 testcases/kernel/syscalls/madvise/madvise06.c diff --git a/runtest/syscalls b/runtest/syscalls index b41c927..732c2ca 100644 --- a/runtest/syscalls +++ b/runtest/syscalls @@ -743,6 +743,7 @@ madvise02 madvise02 madvise03 madvise03 madvise04 madvise04 madvise05 madvise05 +madvise06 madvise06 newuname01 newuname01 diff --git a/testcases/kernel/syscalls/.gitignore b/testcases/kernel/syscalls/.gitignore index 0540928..ffa5db1 100644 --- a/testcases/kernel/syscalls/.gitignore +++ b/testcases/kernel/syscalls/.gitignore @@ -504,6 +504,7 @@ /madvise/madvise03 /madvise/madvise04 /madvise/madvise05 +/madvise/madvise06 /mallopt/mallopt01 /mbind/mbind01 /memcmp/memcmp01 diff --git a/testcases/kernel/syscalls/madvise/madvise06.c b/testcases/kernel/syscalls/madvise/madvise06.c new file mode 100644 index 0000000..bf15a3c --- /dev/null +++ b/testcases/kernel/syscalls/madvise/madvise06.c @@ -0,0 +1,172 @@ +/* + * Copyright (c) 2016 Red Hat, Inc. + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +/* + * DESCRIPTION + * + * Page fault occurs in spite that madvise(WILLNEED) system call is called + * to prefetch the page. This issue is reproduced by running a program + * which sequentially accesses to a shared memory and calls madvise(WILLNEED) + * to the next page on a page fault. + * + * This bug is present in all RHEL7 versions. It looks like this was fixed in + * mainline kernel > v3.15 by the following patch: + * + * commit 55231e5c898c5c03c14194001e349f40f59bd300 + * Author: Johannes Weiner + * Date: Thu May 22 11:54:17 2014 -0700 + * + * mm: madvise: fix MADV_WILLNEED on shmem swapouts + */ + +#include +#include +#include +#include + +#include "test.h" +#include "safe_macros.h" + +char *TCID = "madvise06"; +int TST_TOTAL = 3; + +#ifdef __x86_64__ + +#define GB_SZ (1024*1024*1024) +#define PG_SZ (4*1024) + +static long dst_num; + +static void setup(void); +static int get_page_fault_num(void); +static void test_advice_willneed(void); + +int main(int argc, char *argv[]) +{ + int i, lc; + + tst_parse_opts(argc, argv, NULL, NULL); + + setup(); + + for (lc = 0; TEST_LOOPING(lc); lc++) { + tst_count = 0; + + for(i = 0; i < TST_TOTAL; i++) + test_advice_willneed(); + } + + tst_exit(); +} + +static void setup(void) +{ + struct sysinfo sys_buf; + + sysinfo(&sys_buf); + + dst_num = sys_buf.totalram / GB_SZ; + tst_resm(TINFO, "dst_num = %ld", dst_num); + + tst_sig(NOFORK, DEF_HANDLER, NULL); + if (tst_kvercmp(3, 9, 0) < 0) + tst_brkm(TCONF, NULL, "madvise(MADV_WILLNEED) swap file" + "prefetch available only since 3.9"); + + if (sys_buf.totalram < 2L * GB_SZ) + tst_brkm(TCONF, NULL, "Test requires more than 2GB of RAM."); + if (sys_buf.totalram > 100L * GB_SZ) + tst_brkm(TCONF, NULL, "System RAM is too large, skip this test."); + + TEST_PAUSE; +} + +static int get_page_fault_num(void) +{ + int pg; + + SAFE_FILE_SCANF(NULL, "/proc/self/stat", + "%*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %d", + &pg); + + return pg; +} + +static void test_advice_willneed(void) +{ + int i; + char *src_1gb; + char *dst[100]; + int page_fault_num1; + int page_fault_num2; + + /* allocate source memory (1GB only) */ + src_1gb = mmap(NULL, 1 * GB_SZ, PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_ANONYMOUS, + -1, 0); + if (src_1gb == MAP_FAILED) + tst_brkm(TFAIL | TERRNO, NULL, "mmap failed"); + + /* allocate destination memory (array) */ + for (i = 0; i < dst_num; ++i) { + dst[i] = mmap(NULL, 1 * GB_SZ, PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_ANONYMOUS, + -1, 0); + if (dst[i] == MAP_FAILED) + tst_brkm(TFAIL | TERRNO, NULL, "mmap failed"); + } + + /* memmove source to each destination memories (for SWAP-OUT) */ + for (i = 0; i < dst_num; ++i) + memmove(dst[i], src_1gb, 1 * GB_SZ); + + tst_resm(TINFO, "PageFault(before madvice): %d", get_page_fault_num()); + + /* Do madvice() to dst[0] */ + TEST(madvise(dst[0], PG_SZ, MADV_WILLNEED)); + if (TEST_RETURN == -1) + tst_brkm(TBROK | TERRNO, NULL, "madvise failed"); + usleep(1000); /* wait for read from SWAP */ + + page_fault_num1 = get_page_fault_num(); + tst_resm(TINFO, "PageFault(after madvice / before Mem Access): %d", page_fault_num1); + + *dst[0] = 'a'; + page_fault_num2 = get_page_fault_num(); + tst_resm(TINFO, "PageFault(after madvice / after Mem Access): %d", page_fault_num2); + + if (page_fault_num1 != page_fault_num2) + tst_resm(TFAIL, "Bug has been reproduced!"); + else + tst_resm(TPASS, "Regression test pass!"); + + if (munmap(src_1gb, 1 * GB_SZ) == -1) + tst_brkm(TFAIL | TERRNO, NULL, "munmap failed"); + + for (i = 0; i < dst_num; ++i) { + if (munmap(dst[i], 1 * GB_SZ) == -1) + tst_brkm(TFAIL | TERRNO, NULL, "munmap failed"); + } +} + + +#else +int main(void) +{ + tst_brkm(TCONF, NULL, "Only test on x86_64."); +} +#endif -- 1.8.3.1