Using meminfo information

[Rick Stevens]

On Mon, 2007-07-23 at 13:51 -0700, Waldher, Travis R wrote:
> > -----Original Message-----
> > From: Rick Stevens [mailto:rstevens at internap.com] 
> > Sent: Monday, July 23, 2007 1:10 PM
> > To: Getting started with Red Hat Linux
> > Subject: Re: Using meminfo information
> > 
> > On Mon, 2007-07-23 at 12:54 -0700, Waldher, Travis R wrote:
> > > I am trying to determine how much memory really is in use on the 
> > > system for executing commands.  Would going by "Active" be the most 
> > > accurate?
> > >  
> > > There is 4.8GB of RAM available for processes beyond the 
> > OS, of that 
> > > 3.2GB are in use with 1.9GB free?
> > >  
> > > MemTotal:      6009532 kB
> > > MemFree:        298016 kB
> > > Buffers:        190068 kB
> > > Cached:        4842408 kB
> > > SwapCached:          0 kB
> > > Active:        3256152 kB
> > > Inactive:      1919492 kB
> > > HighTotal:           0 kB
> > > HighFree:            0 kB
> > > LowTotal:      6009532 kB
> > > LowFree:        298016 kB
> > > SwapTotal:     8388600 kB
> > > SwapFree:      8388596 kB
> > > Dirty:              48 kB
> > > Writeback:           0 kB
> > > Mapped:         126552 kB
> > > Slab:           510696 kB
> > > CommitLimit:  11393364 kB
> > > Committed_AS:   198068 kB
> > > PageTables:       3052 kB
> > > VmallocTotal: 2147483647 kB
> > > VmallocUsed:      6144 kB
> > > VmallocChunk: 2147477355 kB
> > 
> > Yes, active is really the number that's involved in programs 
> > (code, BSS and heap).
> > 
> > ----------------------------------------------------------------------
> > - Rick Stevens, Principal Engineer             rstevens at internap.com -
> > - VitalStream, Inc.                       http://www.vitalstream.com -
> > -                                                                    -
> > -                  Heisenberg _may_ have slept here                  -
> > ----------------------------------------------------------------------
> 
> Is it correct to say that the sar command cannot report how much active
> and inactive cache there is?  If it can, I'm not finding it - I can only
> find how much is being used for the cache.  Or in sar land, is that the
> same thing as active in the meminfo file?

The "kbcached" column of "sar -r" reports the amount of cache used.
As far as I know, it can't split active and inactive out.

The active section of /proc/meminfo is what's used for code, BSS and
heap of programs on the run queue (in other words, memory dedicated
to runnable programs).

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- Rick Stevens, Principal Engineer             rstevens at internap.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-      Always remember you're unique, just like everyone else.       -
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