[PATCH i-g-t v2 2/3] lib/igt_device_scan: change device list variable visibility

[Lucas De Marchi]

On Mon, Jan 27, 2025 at 05:49:15AM +0100, Zbigniew Kempczyński wrote:
>On Fri, Jan 24, 2025 at 05:26:25PM +0100, Kamil Konieczny wrote:
>> Hi Zbigniew,
>> On 2025-01-23 at 10:52:07 +0100, Zbigniew Kempczyński wrote:
>>
>> could you improve subject? something like:
>>
>> lib/igt_device_scan: Fix multithreading for Xe
>
>Yes, I can change it to sth like
>
>'lib/igt_device_scan: fix multithreading support in device scanning'
>
>because it also affects i915 even if there's not used there.
>
>>
>> > In commit: 2e8f3e06fb (tests/xe_evict|exec_threads: Use fd reopen
>> > to avoid corrupting global data) I simply changed tests which
>> > corrupted device list global variable. i915 didn't use opening
>> > devices in multithreaded tests but this changed with xe.
>> >
>> > Device scan is now unconditional so we may change device list
>> > variable visibility to TLS. With this reverting of above commit
>> > should be safe (but I'm not sure is it worth to do this).
>> >
>>
>> What about adding Fixes: tag? It is not a kernel so no strict
>> rules here, up to you.
>
>I don't if any freedesktop issue was created for this, maybe Lucas
>knows about it.

fdo issue would use a Closes:, not Fixes:

We do have some issues in which the device "disappears" after certain
tests. They are usually created and closed as "cannot reproduce" after
some time.

I don't think we can point to any bug with 100% confidence it actually
closes it - there may be other bugs lurking around on either kernel or
igt.

For this specific commit (not the one before) maybe we can point to the
commit first using multiple threads, but I don't think it's really
accurate.

Lucas De Marchi

>
>--
>Zbigniew
>
>>
>> > Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
>> > Cc: Lucas De Marchi <lucas.demarchi at intel.com>
>> > Cc: Kamil Konieczny <kamil.konieczny at linux.intel.com>
>>
>> You forgot about:
>> Reviewed-by: Lucas De Marchi <lucas.demarchi at intel.com>
>>
>> LGTM so also:
>> Reviewed-by: Kamil Konieczny <kamil.konieczny at linux.intel.com>
>>
>> > ---
>> >  lib/igt_device_scan.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> > diff --git a/lib/igt_device_scan.c b/lib/igt_device_scan.c
>> > index 44b632008b..c36b0efa90 100644
>> > --- a/lib/igt_device_scan.c
>> > +++ b/lib/igt_device_scan.c
>> > @@ -247,7 +247,7 @@ struct igt_device {
>> >  };
>> >
>> >  /* Scanned devices */
>> > -static struct {
>> > +static __thread struct {
>> >  	struct igt_list_head all;
>> >  	struct igt_list_head filtered;
>> >  	bool devs_scanned;
>> > --
>> > 2.34.1
>> >