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Use MAP_ANONYMOUS|MAP_SHARED instead of unlinked file in /tmp #32

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Use MAP_ANONYMOUS|MAP_SHARED instead of unlinked file in /tmp #32

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7871d2e
Use MAP_ANONYMOUS|MAP_SHARED instead of unlinked file in /tmp
antonblanchard Apr 26, 2021
7c6fb82
Disable THP in shared memory area
antonblanchard Apr 28, 2021
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24 changes: 24 additions & 0 deletions main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,29 @@ extern void __attribute__((weak)) testcase_prepare(unsigned long nr_tasks) { }
extern void __attribute__((weak)) testcase_cleanup(void) { }
extern void *testcase(unsigned long long *iterations, unsigned long nr);

#ifdef __linux__
static char *initialise_shared_area(unsigned long size)
{
char *m;
int page_size = getpagesize();

/* Align to page boundary */
size = (size + page_size-1) & ~(page_size-1);

m = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_SHARED, -1, 0);
if (m == MAP_FAILED) {
perror("initialise_shared_area: mmap");
exit(1);
}

if (madvise(m, size, MADV_NOHUGEPAGE) == -1) {
perror("initialise_shared_area: madvise");
exit(1);
}

return m;
}
#else
static char *initialise_shared_area(unsigned long size)
{
char template[] = "/tmp/shared_area_XXXXXX";
Expand Down Expand Up @@ -65,6 +88,7 @@ static char *initialise_shared_area(unsigned long size)

return m;
}
#endif

static void usage(char *command)
{
Expand Down