On Thu, 2 Aug 2018 00:36:36 +0100 Dmitry Safonov dima@arista.com wrote:
As many other projects, we use some shmalloc allocator. At some point we need to make a part of allocated pages back private to process. And it should be populated straight away. Check that (MAP_PRIVATE | MAP_POPULATE) actually copies the private page.
...
--- /dev/null +++ b/tools/testing/selftests/vm/map_populate.c
...
+#define BUG_ON(condition, description) \
- do { \
if (condition) { \
fprintf(stderr, "[FAIL]\t%s:%d\t%s:%s\n", __func__, \
__LINE__, (description), strerror(errno)); \
exit(1); \
} \
- } while (0)
This is userspace. Why not use assert()?
...
+int main(int argc, char **argv) +{
- int sock[2], child, ret;
- FILE *ftmp;
- unsigned long *smap;
- ftmp = tmpfile();
Seems odd to putz around with stdio when you just want the fd. mkstemp(), maybe?
- BUG_ON(ftmp == 0, "tmpfile()");
- ret = ftruncate(fileno(ftmp), MMAP_SZ);
- BUG_ON(ret, "ftruncate()");
- smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE,
MAP_SHARED, fileno(ftmp), 0);
- BUG_ON(smap == MAP_FAILED, "mmap()");
- *smap = 0xdeadbabe;
- /* Probably unnecessary, but let it be. */
- ret = msync(smap, MMAP_SZ, MS_SYNC);
- BUG_ON(ret, "msync()");
- ret = socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sock);
- BUG_ON(ret, "socketpair()");
- child = fork();
- BUG_ON(child == -1, "fork()");
- if (child) {
ret = close(sock[0]);
BUG_ON(ret, "close()");
return parent_f(sock[1], smap, child);
- }
- ret = close(sock[1]);
- BUG_ON(ret, "close()");
- return child_f(sock[0], smap, fileno(ftmp));
+}
...
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