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

Sam Drinkard sam at wa4phy.net
Mon Jun 5 23:52:50 UTC 2006



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!
>:-(
>
>As normal, while looking at one thing, something else bites my butt. I
>tuned on the swap field in top and sort on it. Here's an edited snippet
>of the results.
>
>Mem:    775708k total,   764752k used,    10956k free,    60780k buffers
>Swap:  1572856k total,      160k used,  1572696k free,   377324k cached
>
>  PID  VIRT  RES  SHR %MEM SWAP COMMAND
>24729  127m  32m  15m  4.3  94m evolution
> 3409 97220 5268 4304  0.7  89m evolution-data-
> 2851  115m  36m 7120  4.8  79m X
>10937  109m  45m  14m  6.0  63m firefox-bin
> 3417 63076 7876 6756  1.0  53m evolution-alarm
> 3363 40332 7284 6228  0.9  32m eggcups
>24745 37480 8176 6876  1.1  28m evolution-excha
> 3736 53272  29m 8660  3.9  22m gnome-terminal
> 3361 44404  21m  10m  2.9  21m nautilus
> 3357 39868  21m  10m  2.8  17m gnome-panel
> 4096 25460 7600 5960  1.0  17m gkrellm
> 3373 20488 3492 2944  0.5  16m gnome-vfs-daemo
> 3367 43608  26m  10m  3.4  16m rhn-applet-gui
> 3359 19904 6128 5316  0.8  13m gnome-volume-ma
> 3387 20904 8068 6696  1.0  12m clock-applet
> 3389 19456 6648 5696  0.9  12m notification-ar
> 3316 19080 7140 5960  0.9  11m gnome-settings-
> 3385 22304  10m 7576  1.4  11m mixer_applet2
> 3244 21508 9960 6868  1.3  11m gnome-session
> 4144 22476  10m 7456  1.4  11m wnck-applet
> 2587 12412 2364 1940  0.3 9.8m gdm-binary
> 2846 13220 3340 2728  0.4 9880 gdm-binary
> 3365 13812 4532 3920  0.6 9280 pam-panel-icon
> 3355 14768 7524 5984  1.0 7244 metacity
> 7182 10328 3436 2280  0.4 6892 sendmail
>18501 11080 4248 1912  0.5 6832 cupsd
>
>Note that the summary line says 160k of swap is used. The man pages say
>the summary and the details under "SWAP" are both reported in "k". No
>mention of "m" is made, I presume that it means "megabytes"?
>
>If so, I can't reconcile what I'm seeing. Free seems to support the
>summary lines.
>
>             total       used       free...
>Mem:        775708     764772      10936...
>-/+ buffers/cache:     326584     449124
>Swap:      1572856        160    1572696
>
>Cat of /proc/meminfo also seems to support the summary lines.
>
>SwapTotal:     1572856 kB
>SwapFree:      1572696 kB
>
>Now, if I treat all those numbers ending in "m" as megabytes, it doesn't
>take long to see that I've been lied to somewhere along the way. Or
>alternatively, I'm dense and "Just Don't Get It" (TM).
>
>Any help?
>  
>
Looked at the same top info, and I don't understand what I see either.  
With processes running, I'm seeing close to 500mb of stuff swapped out, 
but according to free, only the 2.2 mb is swapped.  There's gotta be 
more to this than meets the eye, or something is lying about the swap.  
The system monitor also shows only 2.2mb of swap in use, so where is top 
getting this 500+ mb of swap data from?




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