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> I regularly saw Dock and Finder leak and eat gigabytes of RAM each Make sure to view "Real mem" in Activity Monitor. That's the amount of data actually store

> I regularly saw Dock and Finder leak and eat gigabytes of RAM each Make sure to view "Real mem" in Activity Monitor. That's the amount of data actually stored in your RAM, the rest being swapped out. That number can be quite small, even for apps that theoretically use a lot of memory. I have found Docker to be an "actual" memory hog with not much of it being swapped out, but could imagine that it would be possible in the case of Finder.

Delk 3y ago
I don't know how macOS manages memory or reports its use, but how does the data having been swapped out change anything? If N pages of data of those processes have been swapped out, that means those processes have allocated and used that many pages of memory (plus any that are actually in RAM). The OS heuristics just decided it wasn't worthwhile to keep those particular pages in RAM under current circumstances. If the processes just allocated a lot of memory and never touched it, it might be reasonable to say they don't actually use it because the OS might never actually reserve any physical resources for it. (Happens a lot e.g. in Linux with memory overcommit allowed by default and some processes allocating dozens of gigabytes of virtual memory, most of which they never actually use.) But would those pages then count towards swap use either? Only dirty pages end up in swap. Unless macOS counts allocated but untouched pages towards used swap as committed resources. edit: better wording
vikramkr 3y ago
Swap memory use is worse than actual memory use. If it just reserving a big block and not using it then fine whatever but if it's using a lot of swap that means ram is probably bottlenecking you since swap is slow.
- solarkraft 3y ago
  It's of course slower than real RAM, but Apple are using pretty fast SSDs and possibly a novel model of swapping, making it effectively pretty good (certainly not perfect!).
  - Boatfaceing 3y ago
    [dead]
  - Rebelgecko 3y ago
    Doesn't swapping to SSD make the laptop EOL come even quicker?

Delk 3y ago

I don't know how macOS manages memory or reports its use, but how does the data having been swapped out change anything? If N pages of data of those processes have been swapped out, that means those processes have allocated and used that many pages of memory (plus any that are actually in RAM). The OS heuristics just decided it wasn't worthwhile to keep those particular pages in RAM under current circumstances. If the processes just allocated a lot of memory and never touched it, it might be reasonable to say they don't actually use it because the OS might never actually reserve any physical resources for it. (Happens a lot e.g. in Linux with memory overcommit allowed by default and some processes allocating dozens of gigabytes of virtual memory, most of which they never actually use.) But would those pages then count towards swap use either? Only dirty pages end up in swap. Unless macOS counts allocated but untouched pages towards used swap as committed resources. edit: better wording

vikramkr 3y ago

Swap memory use is worse than actual memory use. If it just reserving a big block and not using it then fine whatever but if it's using a lot of swap that means ram is probably bottlenecking you since swap is slow.

solarkraft 3y ago
It's of course slower than real RAM, but Apple are using pretty fast SSDs and possibly a novel model of swapping, making it effectively pretty good (certainly not perfect!).
- Boatfaceing 3y ago
  [dead]
- Rebelgecko 3y ago
  Doesn't swapping to SSD make the laptop EOL come even quicker?