Re: Zone memory for UMA

From: Randall Stewart <rrs_at_cisco.com>
Date: Sun, 21 Jan 2007 05:32:33 -0500
John Baldwin wrote:
> On Thursday 18 January 2007 08:55, Randall Stewart wrote:
>> Hi all:
>>
>> Query (with flame suit in place :-D)
>>
>> Currently the UMA zone's will hold all memory
>> in them until .. well until the page deamon
>> runs.. or so the "zone_drain()" comment says.. but
>> I can't find that connection either. So I guess
>> not at all :-0
> 
> uma_reclaim() drains all zones when it is called.  It is called by the
> pagedaemon when it is woken up to free some memory.
> 
>> Should we think about adding some sort of garbage
>> collector thread.. that could hang around slowly and
>> periodically look for a zone with large numbers of free
>> pages... and then drain that zone?
> 
> pagedaemon is a sort of GC thread, but it kicks in whenever the system
> is low on memory and asks other subsystems like UMA to free up some
> memory.
> 
Hmm..

Ok I see that path now that its been pointed out... but that
means the crash I saw earlier was one where for some reason
the PD did not wake up in time...

Hmm.. I need to see if I can't recreate that crash ( I was a
month behind and sup'd to current of course)... I would like
to know the circumstances when this occurs :-)

R

-- 
Randall Stewart
NSSTG - Cisco Systems Inc.
803-345-0369 <or> 803-317-4952 (cell)
Received on Sun Jan 21 2007 - 09:33:13 UTC

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