[CentOS] Re: Swap memory: I can't reconcile this stuff.

Wed Jun 7 16:32:01 UTC 2006
Scott Silva <ssilva at sgvwater.com>

Feizhou spake the following on 6/6/2006 7:37 PM:
> William L. Maltby wrote:
>> On Tue, 2006-06-06 at 13:45 +0800, Feizhou wrote:
>>> Sam Drinkard wrote:
>>>>
>>>> William L. Maltby wrote:
>>>>
>>>>> I need to look more into it, but before I start the long and arduous
>>>>> "googling my life away" process, I figured someone might know the
>>>>> answer. I've read the man pages several times and they didn't change!
>>>>> :-(
>>>>>
>>>>> <snip>
>>
>>> most of the 'swapped' data is probably sitting in the cache or buffers?
>>>
>>> Here is an example:
>>>
>>> https://bugzilla.redhat.com/bugzilla/attachment.cgi?id=129064
>>
>> Thanks to the patience and efforts of all, Rodrigo, Les, Sam,
>> Feizhou ... I think I've got a handle on this thing.
>>
>> The only mistake was turning on "SWAP" in top.
>>
>> I can see difficulty in programming to get a *meaningful* swap figure:
>> that is, one that represents either real swapped memory, or its current
>> needs or its potential maximum need. That assumes one can make the
>> decision as to which to show.
>>
>> Others already show (apparently) current swap (free, top's summary
>> lines), so what could one put under the "SWAP" column? I now think that
>> it was the maximum possible swap needed for each process, as you all
>> suggested.
> 
> :)
> 
>>
>> Text shared from program segments and libraries, shared data, buffers,
>> cache, parts already swapped, parts marked for swap but not committed
>> yet,... What would show under the "swap top"? From a programming POV,
>> showing anything but the virtual memory use could be complex and have a
>> tight coupling to the VM implementation details, increasing maintenance
>> for a little used data column too.
>>
>> I am comfortable that "SWAP" only shows the simplest to obtain value and
>> the only problem is that a better explanation is could be provided in
>> the man pages for top.
> 
> Eh? I thought that problem kind of exists for all man pages!
> 
>>
>>> <snip sig stuff>
>>
>> And we do know that a fix for the lock up in Sam's and my machine is
>> apparently in the pipeline for U4.
> 
> If I was a paying customer....
When upstream opens the floodgates of patches, CentOS will have them within a
week, usually less, depending on if they break something.

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