Hmm thinking about it, maybe it does not run the updated code. Ah, got it. Normally when you update Firefox, then try to open a webpage in the “old version” that is currently running in memory, then you can’t show the page; one MUST restart in order to use Firefox further. So this change maybe changes this “forced restart”. This is probably more inline with the other programs in your system, that you can still use and need to restart in order to use the new version. Which makes totally sense. It’s not what I thought, but it probably is.
They now use a zygote process like Chrome does. When a new process is needed, the zygote just forks.
In the old version, the main process used a classic UNIX fork+exec of the browser executable instead, which could start an incompatible process if the executable has been replaced.
With the zygote process, all code and data files are preopened, so replacing or deleting them does not affect the running Firefox.
As another effect, skipping the exec makes process creation faster…
I wonder how they do it. do they just open a handle for all program files at startup that could be needed at any point?
Hmm thinking about it, maybe it does not run the updated code. Ah, got it. Normally when you update Firefox, then try to open a webpage in the “old version” that is currently running in memory, then you can’t show the page; one MUST restart in order to use Firefox further. So this change maybe changes this “forced restart”. This is probably more inline with the other programs in your system, that you can still use and need to restart in order to use the new version. Which makes totally sense. It’s not what I thought, but it probably is.
They now use a zygote process like Chrome does. When a new process is needed, the zygote just forks.
In the old version, the main process used a classic UNIX fork+exec of the browser executable instead, which could start an incompatible process if the executable has been replaced.
With the zygote process, all code and data files are preopened, so replacing or deleting them does not affect the running Firefox.
As another effect, skipping the exec makes process creation faster…
i guess this wouldn’t work on bsd then :/