On Tue, Feb 16, 2010 at 10:56:56AM +0100, Peter Breitenlohner wrote:
> Hi,
>
> I just noticed that 'swapon -av' says:
>
> swapon on /dev/sda2
> swapon: /dev/sda2: found swap v1 signature string for 4 KiB PAGE_SIZE
>
> swapon: /dev/sda2: pagesize=4096, swapsize=3716452352, devsize=8011422720
>
> whereas '/proc/swaps', 'free', and 'top' all report the size as 7823644.
> Where does that number 3716452352 come from?
>
> This is from util-linux-ng-2.16.2, running on Linux 2.6.28.6-x86_64 but
> compiled for 2.6.28.6-i686. As far as I can see from the current git, the
> computations in lib/blkdev.c and mount/swapon.c are still the same.
The number from /proc/swaps is in KiB. The swapsize= from swapon
verbose message is a size calculated from the 'lastpage' field from
swap header.
My laptop:
# swapon -v /dev/sda3
swapon: /dev/sda3: found swap signature: version 1, page-size 4, same byte order
swapon: /dev/sda3: pagesize=4096, swapsize=2410004480, devsize=2410007040
# cat /proc/swaps
Filename Type Size Used Priority
/dev/sda3 partition 2353512 0 -1
swaps: 2353512 * 1024 = 2409996288
swapon: = 2410004480
2410004480 - 2409996288 = 8192
8192 are two pages -- I guess it's the first and last page that are not used
by swap, or so...
Karel
--
Karel Zak <kzak@xxxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe util-linux-ng" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
