[sldev] lltexturefetch.cpp patch for http-textureand/orsnowglobe

[Philippe Bossut (Merov Linden)]

Hi there,

Just to let everybody know that the delicate "1.23 + http-texture"  
merge  is completed and I migrated the result to projects/2009/http- 
texture (aka snowglobe). The builds completed successfully and you can  
now pick the results there:
- Windows: http://secondlife.com/developers/opensource/downloads/2009/http-texture/2324/Second_Life_1-23-2-2324_OSS_Setup.exe
- Darwin: http://secondlife.com/developers/opensource/downloads/2009/http-texture/2324/SecondLife_1_23_2_2324_OSS.dmg
- Linux: http://secondlife.com/developers/opensource/downloads/2009/http-texture/2324/SecondLife-i686-1.23.2.2324.tar.bz2

Those contain steve's patch plus a couple of other fixes he  
contributed internally over the weekend.

Unless folks report catastrophic crashes, we'll be using those  
tomorrow during the test sprint.

Cheers,
- Merov

On May 26, 2009, at 10:13 PM, Philippe Bossut (Merov Linden) wrote:

> Hi,
>
> Thanks for the feedback Sheet. This is great!
>
> I'm in the process of merging fixes from 1.23 as well as this and
> other fixes steve and bao did on http-texture. I'm planning to get the
> whole merge completed by tomorrow noon (I hit a couple of conflicts
> and broken unit tests I needed to fix). If all goes as planned, we
> should have that spiffy new build to play with for the test sprint
> Thursday :)
>
> Cheers,
> - Merov
>
> On May 26, 2009, at 6:13 PM, Sheet Spotter wrote:
>
>> The patch that Steve Linden provided resolves the deadlock I
>> detailed in the
>> comments of VWR-13437.
>>
>> The patch releases a mutex earlier, prior to making one of the calls
>> that
>> led to the deadlock. Releasing the mutex earlier eliminates that
>> deadlock.
>>
>> Previously the HTTP-Texture viewer would hang on me after only a few
>> minutes
>> of moving my camera using Alt-Mouse. After manually applying the
>> patch I
>> have been unable to hang the viewer.
>>
>> Thank you Steve!
>>
>>
>> Sheet Spotter
>>
>> -----Original Message-----
>> From: sldev-bounces at lists.secondlife.com
>> [mailto:sldev-bounces at lists.secondlife.com] On Behalf Of Steve
>> Bennetts
>> Sent: May 26, 2009 11:54 AM
>> To: Second Life Developer Mailing List
>> Subject: Re: [sldev] lltexturefetch.cpp patch for http-texture
>> and/orsnowglobe
>>
>> So, adding that lock exposed a flaw in the logic resulting in a
>> deadlock. Below is the fix for that. The problem was that
>> LLTextureCache::update() was keeping the mutex protecting mReaders[]
>> and
>> mWriters[] locked while calling completed() in the responders,  
>> however
>> readComplete() and writeComplete() (calls to which get triggered by
>> the
>> responders) do their own locking of the mutex, triggering the
>> deadlock.
>> There is no reason for the mutex to be locked while calling these
>> completed() functions.
>>
>> -Steve
>>
>>
>> Index: lltexturecache.cpp
>> ===================================================================
>> --- lltexturecache.cpp    (revision 121571)
>> +++ lltexturecache.cpp    (revision 121572)
>> @@ -779,6 +779,9 @@
>>        }
>>    }
>>
>> +    unlockWorkers();
>> +
>> +    // call 'completed' with workers list unlocked (may call
>> readComplete() or writeComplete()
>>    for (responder_list_t::iterator iter1 = completed_list.begin();
>>         iter1 != completed_list.end(); ++iter1)
>>    {
>> @@ -787,8 +790,6 @@
>>        responder->completed(success);
>>    }
>>
>> -    unlockWorkers();
>> -
>>    return res;
>> }
>>
>>
>>
>> Steve Bennetts wrote:
>>> We will be applying this patch next week, but if someone wants to
>>> play,
>>> I just discovered this major bug in lltexturefetch.cpp:
>>>
>>> void LLTextureFetchWorker::callbackDecoded(bool success, LLImageRaw*
>>> raw, LLImageRaw* aux)
>>> {
>>> +    LLMutexLock lock(&mWorkMutex);
>>>
>>>   ...
>>>
>>>
>>> The missing mutex lock here can cause all sorts of terrible
>>> artifacts.
>>> Don't know if this will fix everything, but it definitely addresses
>>> at
>>> least one of the crashes I have been seeing.
>>>
>>> -Steve
>>>
>>>
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