linux-kernel - Re: fork: Resource temporarily unavailable / cant start new threads

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Date:	Wed, 21 May 2008 15:51:55 -0700
From:	mark <markkicks@...il.com>
To:	"Randy Dunlap" <randy.dunlap@...cle.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: fork: Resource temporarily unavailable / cant start new threads

On Wed, May 21, 2008 at 2:32 PM, Randy Dunlap <randy.dunlap@...cle.com> wrote:
> On Wed, 21 May 2008 14:08:53 -0700 mark wrote:
>
>> On Wed, May 21, 2008 at 1:50 PM, Randy Dunlap <randy.dunlap@...cle.com> wrote:
>> > mark wrote:
>> >>
>> >> On Wed, May 21, 2008 at 1:28 PM, Randy Dunlap <randy.dunlap@...cle.com>
>> >> wrote:
>> >>>
>> >>> On Tue, 20 May 2008 11:26:47 -0700 mark wrote:
>> >>>>
>> >>>> I upgraded to 2.6.25.3-18.fc9.x86_64 fedora core 9, now I get this
>> >>>> error when I try to login to the box, kill a pr start a python app, or
>> >>>> do anything on a regular basis.
>> >>>>
>> >>>> fork: Resource temporarily unavailable
>> >>>>
>> >>>> I have over 10GB RAM free, and zero swap spaced used. The box is a
>> >>>> dual quad core Intel Xeon 5405 with 16GB RAM.
>> >>>>
>> >>>> There is no error message in /var/log/messages or dmesg ...
>> >>>> how do I identify the problem?
>> >>>> thanks!
>> >>>>
>> >>>> uname -a
>> >>>> Linux XXX 2.6.25.3-18.fc9.x86_64 #1 SMP Tue May 13 04:54:47 EDT 2008
>> >>>> x86_64 x86_64 x86_64 GNU/Linux
>> >>>>
>> >>>>
>> >>>> free -m
>> >>>>            total       used       free     shared    buffers     cached
>> >>>> Mem:         16086       3189      12896          0         42
>> >>>>  666
>> >>>> -/+ buffers/cache:       2481      13605
>> >>>> Swap:         1983          0       1983
>> >>>>
>> >>>>
>> >>>> have only 505 processes running
>> >>>> ps aux | wc -l
>> >>>> 505
>> >>>>
>> >>>>
>> >>>> uptime
>> >>>>  11:24:15 up 39 min,  1 user,  load average: 3.54, 3.47, 2.87
>> >>>>
>> >>>> ulimit -a
>> >>>> core file size          (blocks, -c) 0
>> >>>> data seg size           (kbytes, -d) unlimited
>> >>>> scheduling priority             (-e) 0
>> >>>> file size               (blocks, -f) unlimited
>> >>>> pending signals                 (-i) 137216
>> >>>> max locked memory       (kbytes, -l) 32
>> >>>> max memory size         (kbytes, -m) unlimited
>> >>>> open files                      (-n) 32768
>> >>>> pipe size            (512 bytes, -p) 8
>> >>>> POSIX message queues     (bytes, -q) 819200
>> >>>> real-time priority              (-r) 0
>> >>>> stack size              (kbytes, -s) 10240
>> >>>> cpu time               (seconds, -t) unlimited
>> >>>> max user processes              (-u) 1024
>> >>>> virtual memory          (kbytes, -v) unlimited
>> >>>> file locks                      (-x) unlimited
>> >>>
>> >>> The only place that fork() returns EAGAIN is for number of
>> >>> processes being >= its limit.  Does this user already have >= 1024
>> >>> processes?
>> >>
>> >> No, it is around 400
>> >
>> > Well, my comment was wrong anyway.  There are several other tests just
>> > below number of user processes that also return EAGAIN, like:
>> >
>> > - total number of threads being too large
>
> Total number of threads currently running is in /proc/loadavg:
>
>> cat /proc/loadavg
> 1.56 0.58 0.27 2/203 28500
>
> It's the number following the '/', e.g., 203 on my desktop system.
>
> max_threads allowed is a sysctl, so you can tune it if needed.
> It's in /proc/sys/kernel/threads-max:
>
>> cat /proc/sys/kernel/threads-max
> 32624
> I sort of doubt that one is the problem, but you can tell us.

cat /proc/loadavg
0.39 0.45 0.57 1/1412 12032
cat /proc/sys/kernel/threads-max
274432
you are right, i guess this is not the problem.


>> > - error on grabbing a module reference count (?)
>> > - error on grabbing a binfmt module reference
>>
>> as a user how do i identify what is wrong, and fix this? for total
>> number of threads -> is there anyway i can find out if this is causing
>> the problem? my system is running around 80 multi-threaded python web
>> apps.
>
> I can send you some debug patches that will print out the specific
> problem area.  Do you want to do that?  Can you rebuild and install
> a new kernel?
Is it possible to get this debug messages by turning on some flags?
If not yes, pl. send debug patches. its a live box and  I will try to do it!

This is my system / kernel info:
uname -a
Linux XXX 2.6.25.3-18.fc9.x86_64 #1 SMP Tue May 13 04:54:47 EDT 2008
x86_64 x86_64 x86_64 GNU/Linux

thanks a lot!!!!
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