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

[Namhyung Kim]

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.


> +		return;
> +	memset((void *)p_test_llvm__bpf_result, '\0', SHARED_BUF_INIT_SIZE);
> +}
> +
> +void test__llvm_cleanup(void)
> +{
> +	unsigned long boundary, buf_end;
> +
> +	if (!p_test_llvm__bpf_result)

Ditto.

Thanks,
Namhyung


> +		return;
> +	if (p_test_llvm__bpf_result->size == 0) {
> +		munmap((void *)p_test_llvm__bpf_result, SHARED_BUF_INIT_SIZE);
> +		p_test_llvm__bpf_result = NULL;
> +		return;
> +	}
> +
> +	buf_end = (unsigned long)p_test_llvm__bpf_result + SHARED_BUF_INIT_SIZE;
> +
> +	boundary = (unsigned long)(p_test_llvm__bpf_result);
> +	boundary += p_test_llvm__bpf_result->size;
> +	boundary = (boundary + (page_size - 1)) &
> +			(~((unsigned long)page_size - 1));
> +	munmap((void *)boundary, buf_end - boundary);
> +}
> diff --git a/tools/perf/tests/llvm.h b/tools/perf/tests/llvm.h
> new file mode 100644
> index 0000000..1e89e46
> --- /dev/null
> +++ b/tools/perf/tests/llvm.h
> @@ -0,0 +1,14 @@
> +#ifndef PERF_TEST_LLVM_H
> +#define PERF_TEST_LLVM_H
> +
> +#include <stddef.h> /* for size_t */
> +
> +struct test_llvm__bpf_result {
> +	size_t size;
> +	char object[];
> +};
> +
> +extern struct test_llvm__bpf_result *p_test_llvm__bpf_result;
> +extern const char test_llvm__bpf_prog[];
> +
> +#endif
> diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h
> index c804869..a848802 100644
> --- a/tools/perf/tests/tests.h
> +++ b/tools/perf/tests/tests.h
> @@ -27,6 +27,8 @@ enum {
>  struct test {
>  	const char *desc;
>  	int (*func)(void);
> +	void (*prepare)(void);
> +	void (*cleanup)(void);
>  };
>  
>  /* Tests */
> @@ -66,6 +68,8 @@ int test__fdarray__add(void);
>  int test__kmod_path__parse(void);
>  int test__thread_map(void);
>  int test__llvm(void);
> +void test__llvm_prepare(void);
> +void test__llvm_cleanup(void);
>  int test_session_topology(void);
>  
>  #if defined(__arm__) || defined(__aarch64__)
> -- 
> 1.8.3.4
> 
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