On 06/19/2013 08:00 PM, Jan Stancek wrote: > > > > ----- Original Message ----- >> From: "DAN LI" <[email protected]> >> To: "LTP list" <[email protected]> >> Sent: Wednesday, 19 June, 2013 8:52:43 AM >> Subject: [LTP] [PATCH] mmap/mmap12.c: new case to test MAP_POPULATE of mmap >> >> >> Create test case for MAP_POPULATE of mmap. >> >> Verify the following statement >> "For a file mapping,this causes read-ahead on the file. >> Later accesses to the mapping will not be blocked by page faults." >> by mmap-ing a file with specified size and checking change of memory size. >> >> >> Signed-off-by: DAN LI <[email protected]> > > Hi, > > I think this isn't very reliable when you are low on free memory. > I could get it to fail easily just by reading random data to fill cache: > # free -m > total used free shared buffers cached > Mem: 994 704 289 0 0 525 > -/+ buffers/cache: 179 814 > Swap: 2015 0 2015 > > # ./mmap12 > mmap12 1 TFAIL : Seems read-ahead do not work > > > Dropping caches after you create test file might not be bad idea: > system("echo 1 > /proc/sys/vm/drop_caches"); > because I think sysinfo() sees that as used memory. > And also making sure there is enough free mem (say 2x of testfile)
Maybe i could cut the length of the mapping, and as you suggested, drop caches, check if there is enough free mem before testing, to make it more reliable. > > It's still approximate, but I'm not sure if there's better way, > considering other options: > reading /proc/pid/io for read_bytes > reading /proc/pid/pagemap and checking that those pages are present I'll try this first. :) Regards, DAN LI > > Regards, > Jan > >> --- >> testcases/kernel/syscalls/mmap/mmap12.c | 163 >> ++++++++++++++++++++++++++++++++ >> 1 file changed, 163 insertions(+) >> create mode 100644 testcases/kernel/syscalls/mmap/mmap12.c >> >> diff --git a/testcases/kernel/syscalls/mmap/mmap12.c >> b/testcases/kernel/syscalls/mmap/mmap12.c >> new file mode 100644 >> index 0000000..4092806 >> --- /dev/null >> +++ b/testcases/kernel/syscalls/mmap/mmap12.c >> @@ -0,0 +1,163 @@ >> +/* >> + * Copyright (c) 2013 FNST, DAN LI <[email protected]> >> + * >> + * 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 2 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, write to the Free Software >> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 >> USA >> + */ >> + >> +/* >> + * Test Description: >> + * Verify MAP_POPULATE works fine. >> + * "For a file mapping, this causes read-ahead on the file. >> + * Later accesses to the mapping will not be blocked by page faults" >> + * >> + * Expected Result: >> + * mmap() with MAP_POPULATE should succeed returning the address of the >> + * mapped region and this file has been read into RAM, so RAM should >> + * is reduced by at least size of file. >> + */ >> +#include <stdio.h> >> +#include <stdlib.h> >> +#include <sys/types.h> >> +#include <errno.h> >> +#include <unistd.h> >> +#include <fcntl.h> >> +#include <string.h> >> +#include <signal.h> >> +#include <stdint.h> >> +#include <sys/stat.h> >> +#include <sys/mman.h> >> +#include <sys/shm.h> >> +#include <sys/sysinfo.h> >> + >> +#include "test.h" >> +#include "usctest.h" >> + >> +#define TEMPFILE "mmapfile" >> +#define MMAPSIZE (400UL<<20) >> +#define FLUCTUATION (50UL<<20) >> + >> +char *TCID = "mmap12"; >> +int TST_TOTAL = 1; >> + >> +static char *addr; >> +static int fildes; >> +static struct sysinfo info; >> +static unsigned long long freeram_before; >> +static unsigned long long freeram_after; >> + >> +static void loop_setup(void); >> +static void loop_cleanup(void); >> +static void setup(void); >> +static void cleanup(void); >> + >> +int main(int argc, char *argv[]) >> +{ >> + int lc; >> + int ret = 0; >> + char *msg; >> + >> + msg = parse_opts(argc, argv, NULL, NULL); >> + if (msg != NULL) >> + tst_brkm(TBROK, NULL, "OPTION PARSING ERROR - %s", msg); >> + >> + setup(); >> + >> + for (lc = 0; TEST_LOOPING(lc); lc++) { >> + >> + tst_count = 0; >> + >> + loop_setup(); >> + >> + errno = 0; >> + addr = mmap(NULL, MMAPSIZE, PROT_READ | PROT_WRITE, >> + MAP_FILE | MAP_PRIVATE | MAP_POPULATE, fildes, 0); >> + >> + if (addr == MAP_FAILED) { >> + tst_resm(TFAIL | TERRNO, "mmap of %s failed", TEMPFILE); >> + continue; >> + } >> + >> + if (STD_FUNCTIONAL_TEST) { >> + ret = sysinfo(&info); >> + if (ret != 0) >> + tst_brkm(TFAIL, cleanup, "sysinfo failed"); >> + freeram_after = >> + (unsigned long long)info.freeram * >> + (unsigned long long)info.mem_unit; >> + >> + if ((freeram_before - freeram_after) >= >> + (MMAPSIZE - FLUCTUATION)) >> + tst_resm(TPASS, >> + "Functionality of mmap() successful"); >> + else >> + tst_resm(TFAIL, >> + "Seems read-ahead do not work"); >> + } >> + loop_cleanup(); >> + } >> + >> + cleanup(); >> + tst_exit(); >> + >> +} >> + >> +static void loop_setup(void) >> +{ >> + int ret; >> + >> + fildes = open(TEMPFILE, O_RDWR | O_CREAT, 0666); >> + if (fildes < 0) >> + tst_brkm(TFAIL, cleanup, "opening %s failed", TEMPFILE); >> + >> + >> + if (ftruncate(fildes, MMAPSIZE) < 0) >> + tst_brkm(TFAIL | TERRNO, cleanup, "ftruncate file failed"); >> + >> + ret = sysinfo(&info); >> + if (ret != 0) >> + tst_brkm(TFAIL, cleanup, "sysinfo failed"); >> + >> + freeram_before = >> + (unsigned long long)info.freeram * >> + (unsigned long long)info.mem_unit; >> +} >> + >> +static void loop_cleanup(void) >> +{ >> + if (munmap(addr, MMAPSIZE) != 0) >> + tst_brkm(TFAIL | TERRNO, NULL, "munmap failed"); >> + >> + close(fildes); >> +} >> + >> +static void setup(void) >> +{ >> + tst_sig(FORK, DEF_HANDLER, cleanup); >> + >> + if ((tst_kvercmp(2, 6, 23)) < 0) >> + tst_brkm(TCONF, NULL, >> + "This test can only run on kernels that are 2.6.23 and " >> + "higher"); >> + >> + TEST_PAUSE; >> + >> + tst_tmpdir(); >> +} >> + >> +static void cleanup(void) >> +{ >> + TEST_CLEANUP; >> + tst_rmdir(); >> +} >> -- >> 1.8.1 >> >> ------------------------------------------------------------------------------ >> This SF.net email is sponsored by Windows: >> >> Build for Windows Store. >> >> http://p.sf.net/sfu/windows-dev2dev >> _______________________________________________ >> Ltp-list mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/ltp-list >> > ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Ltp-list mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ltp-list
