----- Original Message -----
> From: "DAN LI" <[email protected]>
> To: "LTP list" <[email protected]>
> Cc: "Jan Stancek" <[email protected]>, [email protected], "Caspar Zhang"
> <[email protected]>
> Sent: Tuesday, 25 June, 2013 11:13:27 AM
> Subject: [LTP] [PATCH v2] 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 and check if all pages are present.
>
>
> Signed-off-by: DAN LI <[email protected]>
> ---
> runtest/syscalls | 1 +
> testcases/kernel/syscalls/mmap/mmap12.c | 194
> ++++++++++++++++++++++++++++++++
> 2 files changed, 195 insertions(+)
> create mode 100644 testcases/kernel/syscalls/mmap/mmap12.c
<snip>
> +
> +static int page_check(void)
> +{
> + int pid;
> + int ret;
> + int pm;
> + int num_pages;
> + long index;
> + off_t offset;
> + size_t page_sz;
> + char maps_dev[PATHLEN];
> + char pagemap_dev[PATHLEN];
> + char line[LINELEN];
> + FILE *maps;
> + unsigned long vm_start;
> + unsigned long vm_end;
> + unsigned long long pagemap;
> +
> + page_sz = getpagesize();
> +
> + pid = getpid();
> + sprintf(maps_dev, "/proc/%d/maps", pid);
> + sprintf(pagemap_dev, "/proc/%d/pagemap", pid);
> +
> + maps = fopen(maps_dev, "r");
> + if (maps == NULL)
> + tst_brkm(TFAIL | TERRNO, NULL, "Open dev maps failed");
> +
> + while (fgets(line, LINELEN, maps) != NULL)
> + if (strstr(line, TEMPFILE) != NULL)
> + break;
> +
> + ret = sscanf(line, "%lX-%lX", &vm_start, &vm_end);
Why parsing these 2 from maps? Size is defined by you, and you get vm_start
from mmap().
> + if (ret != 2)
> + tst_brkm(TFAIL | TERRNO, NULL, "Get address space failed");
> +
> + num_pages = (vm_end - vm_start) / page_sz;
> + index = (vm_start / page_sz) * sizeof(unsigned long long);
C99 says long long is _at least_ 64 bits wide. If it's larger than 64, formula
above would break. How about using type, that's exactly 64 bit (uint64_t)?
> +
> + pm = open(pagemap_dev, O_RDONLY);
> + if (pm == -1)
> + tst_brkm(TFAIL | TERRNO, NULL, "Open dev pagemap failed");
> +
> + offset = lseek(pm, index, SEEK_SET);
> + if (offset != index)
> + tst_brkm(TFAIL | TERRNO, NULL, "Reposition offset failed");
> +
> + while (num_pages > 0) {
> + ret = read(pm, &pagemap, sizeof(unsigned long long));
> + if (ret < 0)
> + tst_brkm(TFAIL | TERRNO, NULL, "Read pagemap failed");
> + /*
> + * Check if the page is present.
> + */
> + if (!(pagemap & (1ULL<<63))) {
> + close(pm);
> + fclose(maps);
> + return 1;
> + }
> + num_pages--;
> + }
> +
> + close(pm);
> + fclose(maps);
> +
> + return 0;
> +}
> +
> +static void setup(void)
> +{
> + tst_sig(FORK, DEF_HANDLER, cleanup);
> +
> + if ((tst_kvercmp(2, 6, 25)) < 0)
> + tst_brkm(TCONF, NULL,
> + "This test can only run on kernels that are 2.6.23 and "
Message says 2.6.23, but check is for 2.6.25.
> + "higher");
> +
> + TEST_PAUSE;
> +
> + tst_tmpdir();
> +
> + fildes = open(TEMPFILE, O_RDWR | O_CREAT, 0766);
> + if (fildes < 0)
> + tst_brkm(TFAIL, cleanup, "opening %s failed", TEMPFILE);
> +
> + if (ftruncate(fildes, MMAPSIZE) < 0)
> + tst_brkm(TFAIL | TERRNO, cleanup, "ftruncate file failed");
> +
> +}
> +
> +static void cleanup(void)
> +{
> + close(fildes);
> + TEST_CLEANUP;
> + tst_rmdir();
> +}
> --
> 1.8.1
>
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