SuperPages utilization survey

[Mikolaj Golub]

On Sat, 9 Jun 2012 12:07:40 +0300 Konstantin Belousov wrote:

 KB> Well, if I see a report informing me that some 2M region contains 512 super
 KB> pages, how should I interpret it ? For me, it is only one superpage (mapping)
 KB> that can be created in one 2M region.

Well, if I see a report like below:

  PID              START                END PRT    RES PRES   SUP REF SHD  FL TP PATH
48568        0x800c00000        0x820c00000 rw- 131072    0 51712   2   0 --S df 

it tells me that for the region 0x800c00000-0x820c00000 (512Mb) we have 131072
* 4k = 512Mb resident and 51712 * 4k = 202Mb (a litle less than a half of the
region) promoted (mapped) to superpages.

If I had number of superpages here I would need additional knowledge (a
superpage size) to calculate how effectively superpages are used.

But actually, no much difference for me. To get a number of superpages is it
enough just to divide the result obtained counting normal-sized pages by
(2M/4k) factor?

-- 
Mikolaj Golub