new test system

[libc-test] / src / common / vmfill.c

diff --git a/src/common/vmfill.c b/src/common/vmfill.c
new file mode 100644 (file)
index 0000000..86a218d
--- /dev/null
+++ b/src/common/vmfill.c
@@ -0,0 +1,55 @@
+#include <stdint.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include "test.h"
+#ifndef PAGE_SIZE
+       #define PAGE_SIZE sysconf(_SC_PAGE_SIZE)
+#endif
+
+/* max mmap size, *start is the largest power-of-2 size considered */
+static size_t mmax(int fd, size_t *start)
+{
+       size_t i, n;
+       void *p;
+
+       for (i=n=*start; i>=PAGE_SIZE; i/=2) {
+               if ((p=mmap(0, n, PROT_NONE, MAP_PRIVATE, fd, 0)) == MAP_FAILED) {
+                       n -= i/2;
+               } else {
+                       munmap(p, n);
+                       if (n == i)
+                               *start = n;
+                       n += i/2;
+               }
+       }
+       return n & -PAGE_SIZE;
+}
+
+/*
+fills the virtual memory with anonymous PROT_NONE mmaps,
+returns the mappings in *p and *n in decreasing size order,
+the return value is the number of mappings or -1 on failure.
+*/
+int t_vmfill(void **p, size_t *n, int len)
+{
+       int fd = open("/dev/zero", O_RDWR);
+       size_t start = SIZE_MAX/2 + 1;
+       size_t m;
+       void *q;
+       int i;
+
+       for (i=0;;i++) {
+               m = mmax(fd, &start);
+               if (!m)
+                       break;
+               q = mmap(0, m, PROT_NONE, MAP_PRIVATE, fd, 0);
+               if (q == MAP_FAILED)
+                       return -1;
+               if (i < len) {
+                       p[i] = q;
+                       n[i] = m;
+               }
+       }
+       return i;
+}