[SLE] What is VM and why is it killing my httpd?
Hi list, I found that my apache and sendmail weren't running anymore. After a short inspection of my syslog, I ran into these: Jan 2 01:01:12 suse kernel: VM: killing process httpd Jan 2 01:01:36 suse kernel: VM: killing process httpd Jan 2 01:01:36 suse kernel: VM: killing process sendmail Jan 2 01:01:36 suse kernel: VM: killing process httpd What is VM, and why did it kill httpd and sendmail? I do run a logrotater of my httpd only (no sendmail logs). After the log-mailing, it sighups my httpd. But that occurs at 00:00, not an hour later... TIA, Rogier Maas -- To unsubscribe send e-mail to suse-linux-e-unsubscribe@suse.com For additional commands send e-mail to suse-linux-e-help@suse.com Also check the FAQ at http://www.suse.com/Support/Doku/FAQ/
Rogier Maas wrote:
Hi list,
I found that my apache and sendmail weren't running anymore. After a short inspection of my syslog, I ran into these:
Jan 2 01:01:12 suse kernel: VM: killing process httpd Jan 2 01:01:36 suse kernel: VM: killing process httpd Jan 2 01:01:36 suse kernel: VM: killing process sendmail Jan 2 01:01:36 suse kernel: VM: killing process httpd
What is VM, and why did it kill httpd and sendmail?
I do run a logrotater of my httpd only (no sendmail logs). After the log-mailing, it sighups my httpd. But that occurs at 00:00, not an hour later...
TIA,
Rogier Maas
--
http://www.linux.opennet.ru/base/dev/linuxvm.txt.html says, down the page a little: "Linux cannot swap-out its page tables or page directories. Thus, idle tasks can eat a significant amount of memory. This isn't a big deal for most systems ( small systems: no problem. Big systems: probably have lots of memory anyway ). But, mmap()'d files can create a significant burden if you have a lot of forked processes ( news, sendmail, web server, etc...). Not only does Linux have to scan the page tables for all the processes mapping the file, whether or not they are actively using the page being checked for, but Linux's swapout algorithm scans page tables" and, effectively, makes redundant scans of shared objects. So, I would hazard that your Virtual Memory system (/proc/sys/vm) has been hit by either apache and/or sendmail doing a lot of forking, which is causing VM to halt the forking process??? Maybe you've 'mis-tweeked' some settings? JLK -- To unsubscribe send e-mail to suse-linux-e-unsubscribe@suse.com For additional commands send e-mail to suse-linux-e-help@suse.com Also check the FAQ at http://www.suse.com/Support/Doku/FAQ/
Hi, On Sun, 2 Jan 2000, Rogier Maas wrote:
I found that my apache and sendmail weren't running anymore. After a short inspection of my syslog, I ran into these:
Jan 2 01:01:12 suse kernel: VM: killing process httpd Jan 2 01:01:36 suse kernel: VM: killing process httpd Jan 2 01:01:36 suse kernel: VM: killing process sendmail Jan 2 01:01:36 suse kernel: VM: killing process httpd
What is VM, and why did it kill httpd and sendmail?
I do run a logrotater of my httpd only (no sendmail logs). After the log-mailing, it sighups my httpd. But that occurs at 00:00, not an hour later...
VM stands for virtual memory. Your system was running low on memory and the kernel killed the offending processes to avoid an out of memory situation which could potentially freeze the machine. Here's a comment from Andrea Archangeli (one of our Kernel hackers who wrote this functionality) about this: <SNIP> Yes, they should add more RAM (or more swap) to their machines. The kernel it's not too restrictive but it's only enough secure (the official 2.2.13 kernel can also potentially soft-deadlock in the swapin path in such conditions, while the SuSE kernel survive :). It the task got killed while they had plenty of swap or RAM free that would be true. Please check this. Thanks. </SNIP> Hope that helps, LenZ -- ------------------------------------------------------------------ Lenz Grimmer SuSE GmbH mailto:grimmer@suse.de Schanzaeckerstr. 10 http://www.suse.de/~grimmer 90443 Nuernberg, Germany -- To unsubscribe send e-mail to suse-linux-e-unsubscribe@suse.com For additional commands send e-mail to suse-linux-e-help@suse.com Also check the FAQ at http://www.suse.com/Support/Doku/FAQ/
I have a similar problem. However with 2.2.7 I never seemed to have a problem with virtual memory ( or if I did it was usually the offending process which died as it ran out of memory ). I have 128 MB of RAM and 128 MB of swap. I think that this should be enough. Is it possible to tell the kernel either : not to kill specific processes; or to disable this functionality ? Thanks, CP Lenz Grimmer wrote:
VM stands for virtual memory. Your system was running low on memory and the kernel killed the offending processes to avoid an out of memory situation which could potentially freeze the machine. Here's a comment from Andrea Archangeli (one of our Kernel hackers who wrote this functionality) about this:
<SNIP> Yes, they should add more RAM (or more swap) to their machines.
The kernel it's not too restrictive but it's only enough secure (the official 2.2.13 kernel can also potentially soft-deadlock in the swapin path in such conditions, while the SuSE kernel survive :).
It the task got killed while they had plenty of swap or RAM free that would be true. Please check this. Thanks. </SNIP>
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Hi, On Mon, 3 Jan 2000, C Hennessy wrote:
I have a similar problem. However with 2.2.7 I never seemed to have a problem with virtual memory ( or if I did it was usually the offending process which died as it ran out of memory ).
2.2.7 did not yet include this patch.
I have 128 MB of RAM and 128 MB of swap. I think that this should be enough.
This depends on your application :) Maybe it is running wild and is allocating too much memory due to an error (possible Y2K problem) or memory hole?
Is it possible to tell the kernel either : not to kill specific processes; or to disable this functionality ?
No, there is nothing to tune. If you do not need this feature, you will have to remove this patch. However, it will be part of the official 2.2.14 kernel; Alan Cox has already added Andrea's patches to the 2.2.14pre kernels already. If the kernel runs oom (out of memory), it will kill the offending process (the process trying to allocate additional memory). A vanilla kernel will just lock up. Bye, LenZ -- ------------------------------------------------------------------ Lenz Grimmer SuSE GmbH mailto:grimmer@suse.de Schanzaeckerstr. 10 http://www.suse.de/~grimmer 90443 Nuernberg, Germany -- To unsubscribe send e-mail to suse-linux-e-unsubscribe@suse.com For additional commands send e-mail to suse-linux-e-help@suse.com Also check the FAQ at http://www.suse.com/Support/Doku/FAQ/
participants (4)
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CP.Hennessy＠iname.com -
grimmer＠suse.de -
icarus＠guldennet.nl -
JerryKreps＠alltel.net