[dtrace-discuss] FW: Memory Leak Problem in My Application running on Solaris 10.

[Vladimir Marek]

>  We have real-time application written C++ which runs on Solaris 10  
>  having a problem that's the my application  grows in size from 130 Mb
>  to 450Mb in around 15 days.

Just to be sure that you know, free(3c) does not return memory back to
system. Sorry if I repeat well known fact.

============================= man free(3c) =============================
     The argument to free() is a pointer to  a  block  previously
     allocated  by malloc(), calloc(), or realloc(). After free()
     is executed, this space is made available for further  allo-
     cation  by  the application, though not returned to the sys-
     tem. Memory is returned to the system only upon  termination
     of  the  application.  If   ptr is a null pointer, no action
     occurs. If a random number is passed to free(), the  results
     are undefined.
========================================================================

This means that if you allocate 100Mb buffer, free it and allocate 30Mb
buffer, you will see still 100Mb RSS. C++ delete and delete[] operators
are built on top of the same mechanism.

It is left to the OS to swap out unused memory pages.

[...]

> 1) Is there any way where I can restrict dtrace to look for probe only
> certain source files or functions?

Source files, AFAIK no. Functions yes. I guess that you want to
distinguish between allocations made in some specific functions and the
rest of the allocations ?


> 3) I got a clue of using "libgc.so" which acts as garbage collector is 
>    there any problem in using and how reliable and effective is this.

I would also be interested.

> ( it works fine on sample application but not improvement in real
> application ). I just linked the library "libgc.so" at compile time ?
> Anything else need to done for this ?

For C++ I think that you have to use -library=gc


> Your inputs will be highly appreciated. Please do share your thoughts 
> and techniques.

I would try to make libumem work, it should give you the data.

Not sure if this helps :)
-- 
	Vlad
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