Re: new processes very slow on otherwise responsive system (2.1.
Jim Bauer (jfbauer@home.com)
Sun, 15 Nov 1998 15:02:47 -0500 (EST)
On 15-Nov-98 Simon Kirby wrote:
> On Sat, 14 Nov 1998, Andrea Arcangeli wrote:
>
>> >on both 2.1.127 and 2.1.128, heavy exec() (with a fair bit of I/O)
>> >seems to cause the system to go into a busy wait state. during this
>> >time, it is difficult/impossible/very slow to launch any new
>> >processes.
>>
>> Could you try again on my tree
>> ftp://e-mind.com/pub/linux/kernel-patches/arca-19-...diff.gz and feedback?
>> I changed schedule_timeout() to avoid inserting the timeout timer if the
>> function is been recalled by a proces in in TASK_RUNNING state. That make
>> tons of sense. schedule_timeout() will also log if it's been recalled with
>> a state != TASKrunning or != TASK interruptible.
>
> I just tried 2.1.129pre1 + arca-19 (less the lp stuff that got rejected),
> and I was able to replicate this problem with the kernel compiled to UP.
> It just happened 30 seconds ago, actually, and lasted for about 3 minutes.
> During this time, I filled every console I have with current IP values,
> which I will be looking at shortly to see if I can see where the loop is.
>
> BTW...I triggered this with:
>
> find usr -type f -print | tmp/fork-test 2
>
> ("fork-test" posted on linux-kernel not so long ago)
>
> And it started to freeze up shortly after 11800 children.
I have (yet) to apply the above mentioned patch to 2.1.127 but
I got the freeze to happen with the above fork-test. I can get
it to repeat, but I do have to be in X. It ran without problems
for >21000 iterations when not in X. In X, it usually failed
after 2000-8000 iterations. SysRQ shows lots of free memory.
I could not get this to repeat to save my life yesterday. But
then I was feeding fork-test the same small list of files
over and over again.
BTW, in the freeze before sending this, I did a SysRQ-s & u to
sync and umount everything. It never printed the success messages.
I tried a couple of times too. Then I sent all but init SIGTERM
via SysRQ and then to sync/umount worked.
Jim Bauer, jfbauer@home.com
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