> The whole point is that pagecache does not cause any swap hits.
> Oh my god, it's 2023 and we're still discussing this idea from 1970s.
> Is that so hard to grasp? No, stuff gets evicted from the cache long before you hit the swap, which is by the way measured by page swap-out/in rate and not by how much swap space is used, which is by itself a totally useless metric.
Not everyone has been alive and into this stuff since the 1970s. That you and I know about this is irrelevant for the new people discovering it for the first time. There is always going to be a constant trickle in from new sources, for as long as it takes for the tech to go away. See relevant xkcd: https://xkcd.com/1053/
But it's also worth pointing out that RAM/swap/page cache isn't always as simple as page cache out, RAM in. For example, this question[1] seems to indicate that things aren't as simple as you suggest.
The page cache mechanism is very much alive. That's what we were discussing, is it not? I only lamented the fact that over 50 years the basics of how it works should have become common knowledge but did not.
As for the link you provided, I do think I can get a system in a state like that, and that isn't even untrivial. To push firefox into swap, esp if you have just 8 gigs of it is.. simple. But it is not in any way a normal state of a system. Idk how the author got it in that state.
> Oh my god, it's 2023 and we're still discussing this idea from 1970s.
> Is that so hard to grasp? No, stuff gets evicted from the cache long before you hit the swap, which is by the way measured by page swap-out/in rate and not by how much swap space is used, which is by itself a totally useless metric.
Not everyone has been alive and into this stuff since the 1970s. That you and I know about this is irrelevant for the new people discovering it for the first time. There is always going to be a constant trickle in from new sources, for as long as it takes for the tech to go away. See relevant xkcd: https://xkcd.com/1053/
But it's also worth pointing out that RAM/swap/page cache isn't always as simple as page cache out, RAM in. For example, this question[1] seems to indicate that things aren't as simple as you suggest.
[1]: https://unix.stackexchange.com/questions/756990/why-does-my-...