Re: [PATCH 10/31] perf test: Enforce LLVM test for BPF test

[Wangnan (F)]

On 2015/10/14 23:48, Namhyung Kim wrote:
> On Wed, Oct 14, 2015 at 12:41:21PM +0000, Wang Nan wrote:
> > This patch replaces the original toy BPF program with previous introduced
> > bpf-script-example.c. Dynamically embedded it into 'llvm-src.c'.
> >
> > The newly introduced BPF program attaches a BPF program at
> > 'sys_epoll_pwait()', and collect half samples from it. perf itself never
> > use that syscall, so further test can verify their result with it.
> >
> > Since BPF program require LINUX_VERSION_CODE of runtime kernel, this
> > patch computes that code from uname.
> >
> > Since the resuling BPF object is useful for further testcases, this patch
> > introduces 'prepare' and 'cleanup' method to tests, and makes test__llvm()
> > create a MAP_SHARED memory array to hold the resulting object.
> >
> > Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
> > Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
> > Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> > Cc: Alexei Starovoitov <ast@xxxxxxxxxxxx>
> > Cc: Brendan Gregg <brendan.d.gregg@xxxxxxxxx>
> > Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> > Cc: David Ahern <dsahern@xxxxxxxxx>
> > Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> > Cc: Kaixu Xia <xiakaixu@xxxxxxxxxx>
> > Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
> > Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> > Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> > Cc: Zefan Li <lizefan@xxxxxxxxxx>
> > Cc: pi3orama@xxxxxxx
> > Link: http://lkml.kernel.org/n/ebpf-6yw9eg0ej3l4jnqhinngkw86@xxxxxxxxxxxxxx
> > ---
> [SNIP]
>
> > +void test__llvm_prepare(void)
> > +{
> > +	p_test_llvm__bpf_result = mmap(NULL, SHARED_BUF_INIT_SIZE,
> > +				       PROT_READ | PROT_WRITE,
> > +				       MAP_SHARED | MAP_ANONYMOUS, -1, 0);
> > +	if (!p_test_llvm__bpf_result)
> It should check MAP_FAILED instead.

Fixed by this way:

diff --git a/tools/perf/tests/llvm.c b/tools/perf/tests/llvm.c
index e722e8a..25ddeaf 100644
--- a/tools/perf/tests/llvm.c
+++ b/tools/perf/tests/llvm.c
@@ -199,12 +199,15 @@ void test__llvm_prepare(void)

        for (i = 0; llvm_testcases[i].source; i++) {
                struct test_llvm__bpf_result *result;
+               void *p;

-               result = mmap(NULL, SHARED_BUF_INIT_SIZE,
-                             PROT_READ | PROT_WRITE,
-                             MAP_SHARED | MAP_ANONYMOUS, -1, 0);
-               if (!result)
+               p = mmap(NULL, SHARED_BUF_INIT_SIZE,
+                        PROT_READ | PROT_WRITE,
+                        MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+               if (p == MAP_FAILED)
                        return;
+
+               result = p;
                memset((void *)result, '\0', SHARED_BUF_INIT_SIZE);

                llvm_testcases[i].result = result;

Thank you.

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