3 ms·

> If you happen to launch a large application, or start working with a big file, unused pages will be evicted to disk to make room and, after some slowdown, the

> If you happen to launch a large application, or start working with a big file, unused pages will be evicted to disk to make room and, after some slowdown, the system should become perfectly usable again. YMMV What is an unused page? One that the foreground, memory-hungry application doesn't need? Okay, fine, but what happens when you switch back to some other application? My experience is that it needs the RAM that was paged out, and it doesn't get paged back in all at once. Every time you hit some 4 KiB of memory that happens to be paged out, you wait another 10 ms. I don't know how much beyond the 4 KiB gets paged in at the same time. Worst-case, there's no read-ahead at all. Let's say the application is using 1 GiB of RAM. Then this can happen 262,144 times, which means 44 minutes of waiting in small bursts as you're trying to use it, rather than the 10 seconds (at 100 MB/s) it'd take to read it all in one go. That's what I mean when I say the machine is unusable.

XorNot 10y ago
This is my experience too, and this thread has motivated me to "swapoff" all my desktop systems today I think. There's no situation in which swap usage for me has ever not lead to a reboot due to the system going unresponsive the moment it starts swapping.
- aidenn0 10y ago
  I will posit that your swap is too big then; I have 16GB of ram and run with 1-2GB of swap. A runaway process hits the OOM in about 30s.
  - XorNot 10y ago
    To be fair, this is probably ZFS-on-Linux having a bad swap interaction. But I have found that once I get to 95% RAM use, I start hitting the swap fairly frequently and as a side-effect my desktop starts stuttering (usually happens if I kick off an 8-core code compile). The other culprit I suspect is too many potentially blocking processes Cinnamon's main thread, but I've never figured out a decent way to go after the problem.
    - aidenn0 10y ago
      oh ZoL is terrible with swap; I get OOM all the time when my ARC is still like 4GB.

XorNot 10y ago

This is my experience too, and this thread has motivated me to "swapoff" all my desktop systems today I think. There's no situation in which swap usage for me has ever not lead to a reboot due to the system going unresponsive the moment it starts swapping.

aidenn0 10y ago
I will posit that your swap is too big then; I have 16GB of ram and run with 1-2GB of swap. A runaway process hits the OOM in about 30s.
- XorNot 10y ago
  To be fair, this is probably ZFS-on-Linux having a bad swap interaction. But I have found that once I get to 95% RAM use, I start hitting the swap fairly frequently and as a side-effect my desktop starts stuttering (usually happens if I kick off an 8-core code compile). The other culprit I suspect is too many potentially blocking processes Cinnamon's main thread, but I've never figured out a decent way to go after the problem.
  - aidenn0 10y ago
    oh ZoL is terrible with swap; I get OOM all the time when my ARC is still like 4GB.