Re: [Haskell-cafe] terminateProcess leaves zombie processes around
Quick suggestion: did you try using waitForProcess just after terminateProcess? Cheers, -- Felipe. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] terminateProcess leaves zombie processes around
On Wed, Dec 7, 2011 at 06:47, Dan Rosén d...@student.gu.se wrote: I'm using Haskell to run a lot of instances of an Automated Thorem Prover, eprover. I have pasted a smaller version of my program at http://hpaste.org/54954. It runs eprover sequentially on all input files, with a timeout of 100ms. Unfortunately, it leaves a lot of zombie processes around, probably due to the fact that terminateProcess fails to terminate them, even though eprover terminates on SIGTERM. They *do* terminate; a zombie is a dead process waiting for its parent to reap it with waitForProcess. There's also some POSIX stuff you can do to have them auto-reaped, but doing that correctly and portably is somewhat painful. -- brandon s allbery allber...@gmail.com wandering unix systems administrator (available) (412) 475-9364 vm/sms ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] terminateProcess leaves zombie processes around
On Wed, Dec 7, 2011 at 1:19 PM, Brandon Allbery allber...@gmail.com wrote: They *do* terminate; a zombie is a dead process waiting for its parent to reap it with waitForProcess. There's also some POSIX stuff you can do to have them auto-reaped, but doing that correctly and portably is somewhat painful. But zombie processes do consume a row in the process table, right? If so, then it's bad to have them around. -- Felipe. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] terminateProcess leaves zombie processes around
On Wed, Dec 7, 2011 at 10:27, Felipe Almeida Lessa felipe.le...@gmail.comwrote: On Wed, Dec 7, 2011 at 1:19 PM, Brandon Allbery allber...@gmail.com wrote: They *do* terminate; a zombie is a dead process waiting for its parent to reap it with waitForProcess. There's also some POSIX stuff you can do to have them auto-reaped, but doing that correctly and portably is somewhat painful. But zombie processes do consume a row in the process table, right? If so, then it's bad to have them around. Yes, and they count against the per-uid process limit. -- brandon s allbery allber...@gmail.com wandering unix systems administrator (available) (412) 475-9364 vm/sms ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] terminateProcess leaves zombie processes around
Quoth Felipe Almeida Lessa felipe.le...@gmail.com, On Wed, Dec 7, 2011 at 1:19 PM, Brandon Allbery allber...@gmail.com wrote: They *do* terminate; a zombie is a dead process waiting for its parent to reap it with waitForProcess. There's also some POSIX stuff you can do to have them auto-reaped, but doing that correctly and portably is somewhat painful. But zombie processes do consume a row in the process table, right? If so, then it's bad to have them around. Correct. As noted above, clean up with waitForProcess to release this resource. If it's more convenient, that could be done up front, by forking twice and waiting for the intermediate process. One possibly convenient way to do that might be something like runCommand eprover . Donn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] terminateProcess leaves zombie processes around
Thank you very much for your answers. Felipe's suggestion to use waitForProcess after terminateProcess did the trick. No more zombies around :) Best regards, Dan Rosén On Wed, Dec 7, 2011 at 4:39 PM, Donn Cave d...@avvanta.com wrote: Quoth Felipe Almeida Lessa felipe.le...@gmail.com, On Wed, Dec 7, 2011 at 1:19 PM, Brandon Allbery allber...@gmail.com wrote: They *do* terminate; a zombie is a dead process waiting for its parent to reap it with waitForProcess. There's also some POSIX stuff you can do to have them auto-reaped, but doing that correctly and portably is somewhat painful. But zombie processes do consume a row in the process table, right? If so, then it's bad to have them around. Correct. As noted above, clean up with waitForProcess to release this resource. If it's more convenient, that could be done up front, by forking twice and waiting for the intermediate process. One possibly convenient way to do that might be something like runCommand eprover . Donn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] terminateProcess leaves zombie processes around
On Wed, Dec 7, 2011 at 7:19 AM, Brandon Allbery allber...@gmail.com wrote: On Wed, Dec 7, 2011 at 06:47, Dan Rosén d...@student.gu.se wrote: I'm using Haskell to run a lot of instances of an Automated Thorem Prover, eprover. I have pasted a smaller version of my program at http://hpaste.org/54954. It runs eprover sequentially on all input files, with a timeout of 100ms. Unfortunately, it leaves a lot of zombie processes around, probably due to the fact that terminateProcess fails to terminate them, even though eprover terminates on SIGTERM. They *do* terminate; a zombie is a dead process waiting for its parent to reap it with waitForProcess. There's also some POSIX stuff you can do to have them auto-reaped, but doing that correctly and portably is somewhat painful. You can use a double fork to make this portable and not painful. It's just that you have to fork twice, which can be expensive in some cases. Explanation here: http://stackoverflow.com/a/881434/5113 Here is a Haskell example from xmonad: http://hackage.haskell.org/packages/archive/xmonad/0.7/doc/html/src/XMonad-Core.html#doubleFork If you're planning to send a SIGTERM later, then double forking may make that harder as I think you'd have to communicate the PID up one level. I hope that helps, Jason ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] terminateProcess leaves zombie processes around
On Wed, Dec 7, 2011 at 20:35, Jason Dagit dag...@gmail.com wrote: They *do* terminate; a zombie is a dead process waiting for its parent to reap it with waitForProcess. There's also some POSIX stuff you can do to have them auto-reaped, but doing that correctly and portably is somewhat painful. You can use a double fork to make this portable and not painful. It's just that you have to fork twice, which can be expensive in some cases. And problematic if you're using a pipe to communicate with the child, which seemed quite possible. -- brandon s allbery allber...@gmail.com wandering unix systems administrator (available) (412) 475-9364 vm/sms ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
