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Date:      Sat, 10 Jun 2000 21:58:47 -0700 (PDT)
From:      Kelly Yancey <kbyanc@posi.net>
To:        Dave Hayes <dave@jetcafe.org>
Cc:        freebsd-hackers@FreeBSD.ORG
Subject:   Re: What, exactly, does this mean?
Message-ID:  <Pine.BSF.4.21.0006102146500.24824-100000@gateway.posi.net>
In-Reply-To: <200006110400.VAA22209@hokkshideh.jetcafe.org>

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On Sat, 10 Jun 2000, Dave Hayes wrote:

> [ Please CC me on responses. Thank you. ]
> 
> On 3.3-STABLE the following kernel message appeared recently:
> 
>    pmap_collect: collecting pv entries -- suggest increasing PMAP_SHPGPERPROC
> 
> Is there a place I can get more specific information as to what this
> means, so I can perhaps embark on the road to a correct solution
> and/or interpretation of what happened? Alternatively, can someone
> explain? 
> 

  Sounds like you are running some programs that make heavy use of shared
memory. Do as it says. Basically, pv_entries map logical address to physical
addresses. With lots of shared memory segments, lots of pv_entries exist to
map all of the per-process address mappings to the physical memory backing it.
There are only a certain number of pv_entries that exist in the kernel, and
you are running out (actually, you get this warning when over 90% of them are
used). If you up PMAP_SHPGPERPROC, you increase the number of pv_entries
created at boot time. However, I am not informed enough to say how high you
can safely increase PMAP_SHPGPERPROC.

> On a related note, I took a look at the code and saw the following
> disturbing thing:
> 
[code snipped]
> 
> The machine in question has 57 days of uptime. This code appears to
> imply that I only get to see this 5 times during this period. :)

  How many times do you need to be told? :)

--
Kelly Yancey  -  kbyanc@posi.net  -  Belmont, CA
System Administrator, eGroups.com                  http://www.egroups.com/
Maintainer, BSD Driver Database       http://www.posi.net/freebsd/drivers/
Coordinator, Team FreeBSD        http://www.posi.net/freebsd/Team-FreeBSD/



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