Re: perf-core build fails on powerpc

John Garry
2018-03-14T09:23:48Z

On 14/03/2018 07:10, John Garry wrote:
> On 13/03/2018 21:18, Sukadev Bhattiprolu wrote:
>> John Garry [john.garry@huawei.com] wrote:
>>> On 13/03/2018 20:10, Sukadev Bhattiprolu wrote:
>>>
>>>> Hi John,
>>>>
>>>> I have an xfs file system which seems to have d_type == DT_UNKNOWN
>>>> for all
>>>> entries in 'tools/perf/pmu-events/arch/power8'! readdir(3) says
>>>> ->d_type
>>>> may not be supported by all file systems.
>>>>
>>>> Not relying on ->d_type seems to fix it:
>>>>
>>>
>>> Hi Sukadev,
>>>
>>> Thanks for debugging this. Jiri Olsa (cc'ed) warned me on this, so I
>>> did add
>>> the check for d_type == DT_UNKNOWN.
>>>
>>> But, if all files have d_type == DT_UNKNOWN, you're code would from
>>> visual
>>> observation look to be same as mine (apart from check for '.' or '..'
>>> filename, which I would say is already covered by stat() and
>>> S_ISDIR()). Or
>>> is d_type value just unreliable?
>>
>> In the current code and with DT_UNKNOWN, is_leaf_dir() returns false when
>> it sees the "." or ".." entries right? In the new code, we skip those and
>> return false only if we find some other directory.
>>
>
> OK, that's the real issue, being the "." and ".." entries.
>
> @Arnaldo, I'll try to send a fix for this today. I just need to make an
> xfs to test. Sorry for the hassle.
>

Hi Sukadev,

Even with the xfs I have created I still don't see DT_UNKNOWN. So can
you kindly test this change for me:

diff --git a/tools/perf/pmu-events/jevents.c
b/tools/perf/pmu-events/jevents.c
index 1c018445e757..9f712dafa0b2 100644
--- a/tools/perf/pmu-events/jevents.c
+++ b/tools/perf/pmu-events/jevents.c
@@ -873,7 +873,10 @@ static int is_leaf_dir(const char *fpath)
return 0;

while ((dir = readdir(d)) != NULL) {
- if (dir->d_type == DT_DIR && dir->d_name[0] != '.') {
+ if (!strcmp(dir->d_name, ".") || !strcmp(dir->d_name, ".."))
+ continue;
+
+ if (dir->d_type == DT_DIR) {
res = 0;
break;
} else if (dir->d_type == DT_UNKNOWN) {

It's quite similar to your change, except keeping the check for DT_DIR.

Much appreciated,
John

> John
>
>> Thanks,
>>
>> Sukadev
>>
>>
>>
>