[SOLVED] I still find column SWAP of `top` not zero when I `swapoff`

yaojialuo · 10-14-2012, 03:43 AM

In the same time, I note this on top of `top`
Swap: 0k total, 0k used, 0k free, 45540k cached
can any one explain it or provide some useful links ? Thanks.

druuna · 10-14-2012, 04:13 AM

The cahced column in top isn't part of the swap line (run the free command).

Also have a look here: http://www.linuxhowtos.org/System/Li...Management.htm

yaojialuo · 10-14-2012, 07:41 AM

yeah , you remind me of the page cache.And how about the SWAP column ,it is not displayed unless it is toggled
* P: SWAP = Swapped size (kb)
I get like this and figures are not zero in SWAP column after swapoff
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ SWAP
11961 luo 20 0 282m 21m 2248 S 1.2 4.2 4:08.42 261m
12098 luo 20 0 279m 26m 2348 S 0.0 5.2 2:35.71 253m
25849 luo 20 0 169m 26m 1368 S 0.0 5.4 1:53.30 142m

johnsfine · 10-14-2012, 08:10 AM

The SWAP column in top is useless/redundant information that has very little relationship to the amount of swap space used.

The SWAP column is just the VIRT column minus the RES column. A theory discussion based on the first virtual memory systems in the 1960s and 70s might explain that the swapped size is the virtual size minus the resident size. But memory management in real OSs is more complicated.

yaojialuo · 10-14-2012, 08:35 AM

Fair enough,it's helpful.