Triggering huge-page collapse from user space [LWN.net]

Triggering huge-page collapse from user space

Posted Mar 14, 2022 16:57 UTC (Mon) by Sesse (subscriber, #53779)
Parent article: Triggering huge-page collapse from user space

I originally assumed “collapse” meant that the huge page would collapse and splinter into individual pages, but no, it's the opposite!

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Triggering huge-page collapse from user space

Posted Mar 14, 2022 17:23 UTC (Mon) by droundy (guest, #4559) [Link] (2 responses)

Me too! It's a little more like a black hole collapse...

Triggering huge-page collapse from user space

Posted Mar 14, 2022 20:47 UTC (Mon) by flussence (guest, #85566) [Link]

I'd just think of it like pulling down a shelving unit to free up space for larger items; you're removing structure after all.

In terms of difficulty I'd say huge pages lies somewhere between rearranging occupied shelves without breaking the contents and safely containing a black hole…

Triggering huge-page collapse from user space

Posted Mar 22, 2022 12:53 UTC (Tue) by jezuch (subscriber, #52988) [Link]

FWIW I immediately understood the intended meaning. Caveat: I'm not a native speaker and I read way too much about astrophysics :)

Triggering huge-page collapse from user space

Posted Mar 15, 2022 0:41 UTC (Tue) by Karellen (subscriber, #67644) [Link] (1 responses)

I suppose it's the difference between a solid object collapsing into individual pieces, like a wall collapsing into a disconnected pile of bricks; or a sparsely connected group of elements collapsing into a single mass, like a house of cards collapsing into a dense pile of cards.

Do things generally collapse outwards, or inwards?

Triggering huge-page collapse from user space

Posted Mar 15, 2022 8:16 UTC (Tue) by Wol (subscriber, #4433) [Link]

Think of the energy. It takes an release of energy to make things explode, a minimal flow of energy to make things collapse, while an implosion gives of a blast of energy.

So I guess collapse is the right word here. There's a minimal change observable from outside the system, while what was there is still there, just looking a lot smaller because all the empty space has been squeezed out.

Cheers,
Wol