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There is an OOM kill count in Linux

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Re: There is an OOM kill count in Linux

#31

Post by willcipriano »

gnramires wrote: post #23
magicalhippo wrote: post #16

Earlier quoted context omitted.

This is one area where Windows is far superior to Linux as a desktop experience. By accident, I once wrote an infinite loop that just allocated a bunch of memory. As I ran the program my Windows system quickly became laggy and unresponsive. However, not completely. With a bit of patience I got Task Manager up and managed to kill the process and the system was back to normal within a minute. On Linux, I experience the…

Indeed! I wonder why the system can't just stop giving the process memory when it's starting to become critical? (say, you're over 95% memory used) I really think a more general solution is treating memory (and CPU time as welL!) as a scarce resource, and programs should either: (1) Deal with having severely denied resources (default behavior); (2) Use a communication protocol to negotiate memory with the system. Neg…

> I wonder why the system can't just stop giving the process memory when it's starting to become critical

If you turn swap off the allocator will error out when you are out of memory. I don't think most software handles that error but all the wiring is there to do that.

Re: There is an OOM kill count in Linux

#32

Post by GTP »

magicalhippo wrote: post #16
contrarian1234 wrote: post #7

Out of curiosity, what do people recommend for OOM these days on Linux? My number one recurring issue on Ubuntu is me not noticing the memory usage, running out of memory and locking up my system (forcing a hard reboot and loss of unsaved work) EDIT: I'd preferably like an OOM handler that would freeze my system and pop up a little menu from which I could select which process to nuke

This is one area where Windows is far superior to Linux as a desktop experience. By accident, I once wrote an infinite loop that just allocated a bunch of memory. As I ran the program my Windows system quickly became laggy and unresponsive. However, not completely. With a bit of patience I got Task Manager up and managed to kill the process and the system was back to normal within a minute. On Linux, I experience the…

On the other hand, at least in my experience, Windows becomes laggy much sooner than Linux. IMO which of the two behaviors is better really depends on the use case.

Re: There is an OOM kill count in Linux

#33

Post by samus »

magicalhippo wrote: post #16
contrarian1234 wrote: post #7

Out of curiosity, what do people recommend for OOM these days on Linux? My number one recurring issue on Ubuntu is me not noticing the memory usage, running out of memory and locking up my system (forcing a hard reboot and loss of unsaved work) EDIT: I'd preferably like an OOM handler that would freeze my system and pop up a little menu from which I could select which process to nuke

This is one area where Windows is far superior to Linux as a desktop experience. By accident, I once wrote an infinite loop that just allocated a bunch of memory. As I ran the program my Windows system quickly became laggy and unresponsive. However, not completely. With a bit of patience I got Task Manager up and managed to kill the process and the system was back to normal within a minute. On Linux, I experience the…

Since Linux has Unix-legacy and is usually intended to be used on servers, there is one well-intended assumption at play here: unless different settings are applied, all processes are in principle created equal. This also applies to GUI applications, and means that a single out-of-control application can lock up the whole system.

That's actually fine on multi-user systems. A competent admin would set up tight limits and prevent one user taking over all resources, and intervenes if they mess up. On single-user machines, this limitation is not there because there is effectively only one user. And since desktop Linux is not a priority for most Linux vendors, this scenario sees comparatively little consideration.

In comparison, on Windows some applications (at least explorer.exe and the task manager) seem to have way higher priority. No matter what else is going on, the user must be able to use these application to rein in other applications. The drawback is that there is no recourse should explorer.exe ever lock up.

Re: There is an OOM kill count in Linux

#34

Post by roblabla »

gnramires wrote: post #23
magicalhippo wrote: post #16

Earlier quoted context omitted.

This is one area where Windows is far superior to Linux as a desktop experience. By accident, I once wrote an infinite loop that just allocated a bunch of memory. As I ran the program my Windows system quickly became laggy and unresponsive. However, not completely. With a bit of patience I got Task Manager up and managed to kill the process and the system was back to normal within a minute. On Linux, I experience the…

Indeed! I wonder why the system can't just stop giving the process memory when it's starting to become critical? (say, you're over 95% memory used) I really think a more general solution is treating memory (and CPU time as welL!) as a scarce resource, and programs should either: (1) Deal with having severely denied resources (default behavior); (2) Use a communication protocol to negotiate memory with the system. Neg…

> Maybe this is reinventing the wheel?

I believe something like that exists on mobile platforms for memory, at least on iOS you get a message (applicationDidReceiveMemoryWarning:) when the system is memory starved and wants your app to free memory. If you don't release enough memory and the memory pressure doesn't go down, the system will start killing apps.

Re: There is an OOM kill count in Linux

#35

Post by microtonal »

Kwpolska wrote: post #17
contrarian1234 wrote: post #7

Out of curiosity, what do people recommend for OOM these days on Linux? My number one recurring issue on Ubuntu is me not noticing the memory usage, running out of memory and locking up my system (forcing a hard reboot and loss of unsaved work) EDIT: I'd preferably like an OOM handler that would freeze my system and pop up a little menu from which I could select which process to nuke

Buying more RAM?

At the risk of this being tongue-in-cheeck: if you have a rogue process, any amount of RAM is going to be eaten up.

(It sometimes happens in software development and it's nice if it doesn't take your machine in swap hell as a result.)

Re: There is an OOM kill count in Linux

#36

Post by psyclobe »

magicalhippo wrote: post #16
contrarian1234 wrote: post #7

Out of curiosity, what do people recommend for OOM these days on Linux? My number one recurring issue on Ubuntu is me not noticing the memory usage, running out of memory and locking up my system (forcing a hard reboot and loss of unsaved work) EDIT: I'd preferably like an OOM handler that would freeze my system and pop up a little menu from which I could select which process to nuke

This is one area where Windows is far superior to Linux as a desktop experience. By accident, I once wrote an infinite loop that just allocated a bunch of memory. As I ran the program my Windows system quickly became laggy and unresponsive. However, not completely. With a bit of patience I got Task Manager up and managed to kill the process and the system was back to normal within a minute. On Linux, I experience the…

I’ve noticed this too, make -j and boom hard lock only option is to reboot. Really annoying l! Windows kinda deals with it but it has other issues; I have also noticed this behavior on MacOS.

Re: There is an OOM kill count in Linux

#37

Post by marcodiego »

contrarian1234 wrote: post #7

Out of curiosity, what do people recommend for OOM these days on Linux? My number one recurring issue on Ubuntu is me not noticing the memory usage, running out of memory and locking up my system (forcing a hard reboot and loss of unsaved work) EDIT: I'd preferably like an OOM handler that would freeze my system and pop up a little menu from which I could select which process to nuke

Is this still the case on a modern distro using MGLRU and systemd-oomd?

Re: There is an OOM kill count in Linux

#38

Post by chrismorgan »

manymatter wrote: post #9
contrarian1234 wrote: post #7

Out of curiosity, what do people recommend for OOM these days on Linux? My number one recurring issue on Ubuntu is me not noticing the memory usage, running out of memory and locking up my system (forcing a hard reboot and loss of unsaved work) EDIT: I'd preferably like an OOM handler that would freeze my system and pop up a little menu from which I could select which process to nuke

I've never had that problem. Maybe you don't setup much swap space as I would expect the system to run well enough to save your work and shutdown for most common leaks.

My previous Linux laptop with 8GB of RAM (2014–2017 or so, I think) I never even got round to setting up swap, and I only ran into problems two or three times total (when running two or three Firefox instances and Chromium and a VM taking 2GB and a bunch of other things running—some of the biggest consumers, namely browsers, actually notice if they’re using too much of your RAM and adjust how they work so they don’t ask for so much RAM, at what I believe is a fairly slight performance cost).

On my current laptop and with my current habits, I’m consuming a lot more memory, and so the technique I use to avoid OOM is simply having 40GB of RAM. (As it happens, I do actually have swap set up at present, because certain circumstances meant I wanted to hibernate it occasionally; should disable swap again now I’m back to not needing to hibernate.)

Re: There is an OOM kill count in Linux

#40

Post by DefineOutside »

contrarian1234 wrote: post #7

Out of curiosity, what do people recommend for OOM these days on Linux? My number one recurring issue on Ubuntu is me not noticing the memory usage, running out of memory and locking up my system (forcing a hard reboot and loss of unsaved work) EDIT: I'd preferably like an OOM handler that would freeze my system and pop up a little menu from which I could select which process to nuke

Look into oom_kill_allocating_task. There's likely a better solution such as an earlier OOM, but killing the wrong process seems better than locking the system.
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