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memory leaks



I still have not gotten a response to this problem. I would appreciate some
answer.. The following message contains the entire thread of communication
thus far.

Thanks in advance.

Mark Schapira
---------------------- Forwarded by Mark Schapira/DEN/HID on 05/22/2001
12:55 PM ---------------------------


Mark Schapira
05/16/2001 09:36 AM

To:   jffs-dev@xxxxxxx.com
cc:
Fax to:
Subject:  memory leaks when writing to a file in /mnt/flash

I have been communicating with Jonas Adolfsson with regard to this problem.
However, he informed me that he will be on vacation for the next few days
and he suggested that I resubmit this email to dev-etrax@xxxxxxx.com and
dev-jffs@xxxxxxx. Below the *************** is the chain of correspondance
so far.

In answer to Jonas's latest questions.
The problem occurs with Linux 2.4 for the Etrax 100 LX
The results from /proc/meminfo are confusing to me because they are
inconsistent. ie. the total uses of memory do not add up to the total
amount of memory
that is available so I can't determine how the memory is used.

I suspect that the problem occurs with the jffs file system because I have
mounted an nfs drive on the Linux 2.4.3 and I DO NOT experience this
problem.

I do not know how the jffs and the flash device work (in detail) so I have
no idea how I can run out of memory  by writing records into a file in the
/mnt/flash directory. Is there any doumentation that describes how the jffs
works?

I am attaching the .tgz file that demonstrates this problem.

(See attached file: writetest.tgz)

Thanks in advance.


Mark Schapira

***********************************************************************************************************
What does meminfo say that the memory is used for?
It may be a JFFS problem, since ju make a lot of small
writes to the JFFS there will probably be a lot of small fragments
written to the flash, and these will have some kind of
representation in memory as well.
Garbage collection should eventually merge the fragments
and reduce the representation as well.

I will take some time off since I recently became a father to
a small boy, so I suggest you send a new mail to dev-etrax
and possibly jffs-dev as well.

Is this with elinux or Linux 2.4?

/Johan

----- Original Message -----
From: Mark Schapira <mschapira@xxxxxxx.com>
To: <johana@xxxxxxx.com>
Sent: Tuesday, May 15, 2001 6:10 PM
Subject: Re: memory leaks when writing to a file


>
> Hi Johan,
>
> In answer to your questions:
>
> I am writing the file into the /mnt/flash directory.
>
> If I
> cat /proc/meminfo
> ./writetest tfile 10000
> cat /proc/meminfo
>
> The 2nd cat /proc/meminfo show that the amount of free memory has
> significantly decreased.
>  In fact if I did the following:
> cat /proc/meminfo
> ./writetest tfile 10000
> cat /proc/meminfo
> ./writetest tfile 10000
> cat /proc/meminfo
> ./writetest tfile 10000
> cat /proc/meminfo
> ./writetest tfile 10000
> .......................................
>
> I would eventually hang the system so bad that the only way to recover
> would be to reflash the system.
>
> I do not intentionally want to cache the file, I intend for the contents
> to go to the flash device. The program simply creates n records and
writes
> each record to a file.
>
> If I mount an nfs directory I do not get this symptom.
>
> Please compile and run my test program and I think that you will see that
I
> am loosing memory.
>
> Thanks in advance.
>
> Mark
>
>
>
>
>
> johan.adolfsson@xxxxxxx.com on 05/14/2001 04:43:43 PM
>
> Please respond to <johan.adolfsson@xxxxxxx.com>
>
> To:   <dev-etrax@xxxxxxx.com>
> cc:
> Fax to:
> Subject:  Re: memory leaks when writing to a file
>
> Isn't it just that the file written is cached?
> Examine /proc/meminfo closer or post it here
> (version before and after the program is executed)
> Also, what filename are you using?
> (are you writing to /tmp/, /etc/  or /mnt/flash/ ?)
>
> /Johan
>
>
> ----- Original Message -----
> From: Mark Schapira <mschapira@xxxxxxx.com>
> To: <dev-etrax@xxxxxxx.com>
> Sent: Monday, May 14, 2001 8:24 PM
> Subject: memory leaks when writing to a file
>
>
> > When I write to a file from a c++ class , I find that memory leaks
occur.
> > This is especially true if I make a relatively large number of writes.
> > When I execute:
> > cat /proc/meminfo
> > run the program in question.
> > cat /proc/meminfo
> > The second /cat/procmeminfo shows that the amount of memory available
is
> > considerably less.
> > I have run some tests and I have determined that writing to the file
> causes
> > the memory leak.
> >
> > I am attaching a .tgz file which will illustrate this problem.
> >
> > Please let me know why the memory leak occurs.
> >
> > Thanks in advance.
> >
> > Mark Schapira
> >
> >
> > (See attached file: writetest.tgz)
>





writetest.tgz