Re: [Masf-restricted-dev] CR/CN: Fixed thread-safety issues in HXScheduler

Commited to:
HEAD
hxclient_3_4_0_atlas
hxclient_3_1_0_atlas

Petar


On Sat, Sep 6, 2008 at 6:47 AM, Milko Boic <[email protected]> wrote:
>
> Excellent find and fix!!!
>
> Please commit to the following additional branches as well:
> hxclient_3_1_0_atlas
> HEAD
>
> Thanks,
> Milko
>
> At 06:14 PM 9/5/2008, Petar Basic wrote:
>
> Modified by: pbasic at real.com
> Date: 2008/09/06
> Project: strummer
>
> Synopsis:
> Fixed thread-safety issues in HXScheduler
>
> Details:
> There was a race condition in ClientPQ class.
> ClientPQ is derived from PQ which accepts CHXID object as an argument
> to the constructor.  ClientPQ is obviously designed as a thread-safe
> wrapper around PQ, but each instance of ClientPQ uses its own mutex
> object.  However, this is not enough.  Since CHXID object can be
> shared among PQ instances, it must be protected by a single mutex.
> Instantiations of ClientPQ in HXScheduler are critical to this case
> since HXScheduler uses 3 ClientPQ objects which share a single CHXID.
> HXOptimizedScheduler currently uses only 1 ClientPQ object.
>
> 1.) Additional assert statements which can detect race condition have
> been added to CHXID class.
> 2.) ClientPQ is modified to accept externally created mutex.  In this
> way CHXID object can be protected through common mutex by multiple
> ClientPQ instances.
> 3.) Destruction of PQ base in ClientPQ destructor has been made thread-safe.
> 4.) HXScheduler has been modified to use a single mutex with all of
> its ClientPQ instances.
> 5.) Although it was not necessary at this time, HXOptimizedScheduler
> has been modified in the same way as HXScheduler to prepare it for
> possible future updates.
>
> Testing:
> Performed over 1200 transcoding transfers to USB memory during single
> VFMM session without crashes or lockups.  Also performed simultaneous
> transfers to 2 USB devices without crashes or lockups.
>
> Files Modified:
> common/util/pub/id.h
> common/system/pub/pq.h
> common/system/pq.cpp
> client/common/system/pub/clientpq.h
> client/common/system/clientpq.cpp
> client/common/system/pub/hxsched.h
> client/common/system/hxsched.cpp
> client/common/system/pub/hxoptsc.h
> client/common/system/hxoptsc.cpp
>
> Platforms and Profiles Build Verified:
> system id: win32-i386-vc7
> profile: helix-dtdr-all-defines
>
> Platforms and Profiles Functionality Verified:
> x86 Windows XP SP2
>
> Branch:
> hxclient_3_4_0_atlas
>
> Copyright assignment:
> I am a RealNetworks employee or contractor.
>
> Content-Type: application/octet-stream; name="common_util.diff"
> X-Attachment-Id: f_fkrjl7q00
> Content-Disposition: attachment; filename=common_util.diff
>
> Content-Type: application/octet-stream; name="common_system.diff"
> X-Attachment-Id: f_fkrjlb201
> Content-Disposition: attachment; filename=common_system.diff
>
> Content-Type: application/octet-stream; name="client_common_system.diff"
> X-Attachment-Id: f_fkrjld282
> Content-Disposition: attachment; filename=client_common_system.diff
>
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>

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