X-Git-Url: http://nsz.repo.hu/git/?p=libc-test;a=blobdiff_plain;f=src%2Fcommon%2Fvmfill.c;fp=src%2Fcommon%2Fvmfill.c;h=86a218d15d9884799ea92655424f36fe1b86a463;hp=0000000000000000000000000000000000000000;hb=cfa23cc1bd01f5c44d7746b8b1839f84d5e1b6eb;hpb=b775d19f7ff58da3fe009d48742068cc92a274f2

diff --git a/src/common/vmfill.c b/src/common/vmfill.c
new file mode 100644
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;
+}