[omniORB] modifications to omni_thread
Jonathan Clark
jc@jonathanclark.com
Fri, 7 Jul 2000 13:38:05 -0700
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RE: [omniORB] memory allocation/free under Win32The omni_thread class has a
sub-class called init_t whose purpose is to initialize the
thread system. The way it is declared, init_t will be executed every time a
thread is
created - when really it is only needed once. To deal with this, you have a
check at
init_t::init_t()
if (count++ != 0) // only do it once however many objects get created.
return;
In some pathological cases this check could fail (it's not thread safe).
Unless omni_threads
are always created from the main thread? Also init_t() calls new() to
allocate a omni_mutex
and a omni_thread. Because there is a global instance of init_t declared,
new() will be called
before main. This is bad (see my previous email about memory allocation).
So - to fix both,
I removed init_t from the omni_thread class and created a static member
function
omni_thread::global_init() function that is called from ORB_init.
Is there anything that requires the thread system to be initialized before
ORB_init?? From
my examination of the source, it doesn't look like it...
One final note, it looks like the objects created by init_t are never
destroyed. Only a 2 object leak,
so no big deal - but thought you might want to know.
Jonathan
btw, should I report things like this to the list or directly to the AT&T
staff?
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<HTML><HEAD><TITLE>RE: [omniORB] memory allocation/free under =
Win32</TITLE>
<META http-equiv=3DContent-Type content=3D"text/html; =
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<BODY>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>The=20
omni_thread class has a sub-class called init_t whose purpose is to =
initialize=20
the</FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>thread=20
system. The way it is declared, init_t will be executed every time =
a=20
thread is</FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>created - when really it is only needed once. To deal =
with this,=20
you have a check at</FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>init_t::init_t()</FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2> if (count++ !=3D 0) // only do it once =
however many=20
objects get created.<BR> =
return;</FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>In=20
some pathological cases </FONT></SPAN><SPAN =
class=3D464353919-07072000><FONT=20
face=3DArial color=3D#0000ff size=3D2>this check could =
</FONT></SPAN><SPAN=20
class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>fail (it's not=20
thread safe). Unless omni_threads</FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>are=20
always created from the main thread? </FONT></SPAN><SPAN=20
class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>Also init_t()=20
calls new() to allocate a omni_mutex </FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>and a=20
omni_thread. Because there is a </FONT></SPAN><SPAN=20
class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>global instance=20
</FONT></SPAN><SPAN class=3D464353919-07072000><FONT face=3DArial =
color=3D#0000ff=20
size=3D2>of init_t declared, new() will be called </FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>before=20
main. This is bad (see my previous email </FONT></SPAN><SPAN=20
class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>about memory=20
allocation). So - to fix both, </FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>I=20
removed init_t from the omni_thread class </FONT></SPAN><SPAN=20
class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>and created a=20
static member function </FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>omni_thread::global_init() function that is called from =
ORB_init. =20
</FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>Is=20
there anything that </FONT></SPAN><SPAN class=3D464353919-07072000><FONT =
face=3DArial color=3D#0000ff size=3D2>requires the thread system to be =
initialized=20
before ORB_init?? From</FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>my=20
examination of the source, it doesn't look like =
it...</FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>One=20
final note, it looks like the objects created by init_t are =
never=20
destroyed. Only a 2 object leak,</FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>so no=20
big deal - but thought you might want to know.</FONT></SPAN></DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>Jonathan</FONT></SPAN></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2></FONT> </DIV>
<DIV><SPAN class=3D464353919-07072000><FONT face=3DArial color=3D#0000ff =
size=3D2>btw,=20
should I report things like this to the list or directly to the AT&T =
staff?</FONT></SPAN></DIV></BODY></HTML>
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