[sane-devel] memory problem

[Gerhard Jaeger]

Hi,

On Thursday 26 August 2004 09:42, Oliver Schirrmeister wrote:
[SNIPSNAP]
> > as long as you run the stuff on linux, I suggest to use the process
> > model and NOT the pthread model. The pthread implementation
> > on Linux is somewhat crappy.
>
> Shouldn't I use pthreads on Linux at all or only the sanei_thread
> functions? Do you know some references about that topic?

sanei_thread only encapsulates pthread. In the end what you observe
should not happen. But if there's no reason for using pthreads, don't use it.

Reference with a lot of links (currently only in the google cache):
http://www.google.de/search?q=cache:NB5cC9eZ4RIJ:www.yolinux.com/TUTORIALS/LinuxTutorialPosixThreads.html+pthread+linux&hl=de&ie=UTF-8

LinuxThreads FAQ:
http://pauillac.inria.fr/~xleroy/linuxthreads/faq.html
http://www-124.ibm.com/pthreads/


> I'm calling the sane functions from java. Using fork() duplicates the
> fat java-process.

That's what fork() is designed for ;)

> > Anyway it should not happen, that all of your memory will be used,
> > so I'm pretty sure that you missed something obvious.
> > What about linking the libs statically and using valgrind or efence?
>
> I've linked the sane backends statically with the 'frontend'. The problem
> is the same. The pthread lib is linked dynamically.
> I've tried valgrind. That revealed only two 'real' memory leaks in some
> init-routines of sanei_usb, the test backend and the pthread library,
> nothing severe.

Is the sanei_usb memory-leak related to the patch you've sent me?

> Under control of valgrind the vm-size doesn't increase !?!

Hmmm, strange...
anybody out there with some ideas?
On what box are you working? Kernel-Version and glibc Version?

Ciao,
  Gerhard


> >
> > On Wednesday 25 August 2004 17:49, Oliver Schirrmeister wrote:
> > > Hi,
> > >
> > > I'm trying to find a memory leak in the fujitsu backend.
> > > When I do a duplex scan (for example with scanadf) the vm-size
> > > of the process increases aproximatly the size of one image
> > > (for example ~4MB for DIN-A5-gray and ~8MB for DIN-A4-gray
> > > at 300dpi). So all 250 sheets when the process reaches the 2GB
> > > limit I run into problems.
> > >
> > > I've configured sane to use pthreads and use sanei_thread_begin
> > > to fork a reader thread that reads the data from the scanner and
> > > writes it into two pipes (one for the frontside and one for the
> > > backside).
> > >
> > > The scanner returns the image data in alternate order, one block
> > > frontside, one block backside ...
> > > So I write the front side data directly to the frontside-pipe and
> > > write the backside data in a buffer of the size of the image.
> > > When the transfer is complete, I write that buffer into the backside
> > > pipe.
> > > I've checked it several times. I'm really freeing that buffer. The
> > > address I free is really the address I got from alloc.
> > >
> > > If I don't use a pipe for the backside and use a file (so I don't have
> > > to allocate that buffer) there is no problem.
> > >
> > > When I don't use threads (--enable-fork-process=YES) I don't have
> > > problems because the reader process terminates and frees all memory. So
> > > I think the problem is in the reader thread.
> > >
> > > I'm not killing the reader thread. I think it should terminate when the
> > > reader-procedure ends.
> > >
> > > Any suggestions are welcome.
> > >
> > > Oliver