[mod_python] Resource consumption

Neo Eureka neo at https.ru
Mon Sep 8 16:59:20 EST 2003

Hi all!


IIUC, shared memory and semaphores are allocated even if I don't use
sessions or PSP at all ? Is there a way to completely "switch off"
the features I do not (and will not) use ever ? It seems very strange
to me: features that I do not use still consume system resources and
cause problems with server startup (yes, I've got RedHat box).

> On Sat, 6 Sep 2003, Conrad Steenberg wrote:

>> This prompts a change in the kernel semaphore settings on older linuxes
>> (redhat 7.3 specifically).

> Well - I think this is really a redhat problem. I believe I even saw
> something reporting it as a security problem - it is very easy for someone
> to deprive an rh box of available semaphores. I wonder what the default is
> on rh 8 and 9 (anyone?).

>> As this will likely trip up new sysadmins that just want to try out the
>> package,

> It probably will :-(
> But that's why there is a "Hint" in the error log for Linux users.

>> is there a way to reduce the number of sessions (or space for
>> these sessions) by using a directive?

> Yes, there is a way - adjust MaxClients. Some MPM's (at least worker) will
> alter MaxClients if the other directives do not add up to or exceed it, so
> it's possible other values may need adjusting.

> BTW, mod_python does NOT quit if it was able to allocate *some* locks, but
> not *all*, it only writes a warning to the error log and proceeds. But
> what craps out after that is mod_rewrite, which wants a global lock, but
> mod_python has eaten them all. So perhaps I can adjust it so that if we
> allocated *some* but not *all*, then to free one (or two?)  so that
> mod_rewrite is happy.

> (On the other hand doing this may seem like going too far to adress what
> is really a lousy config default in the kernel....)

> Grisha

Neo Eureka / mailto:neo at https.ru

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