Regarding MakeCallback()

[deostroll]

Which MakeCallback() implememtation is called here 👉https://github.com/nodejs/node/blob/52e4fb5b23157222d85b9275f7ccdfa88fe88d0f/src/node_file.cc#L581

Is it this?

What about the case about the same call from here?

Will it execute js code immediately? If so, how can I convince my self that it won't run concurrently when say two IO tasks simultaneously finished and wants to make a js callback?

Ps: I was tracing how fs.readFile() works under the hood.

[jasnell]

IO tasks do not run simultaneously. All of the IO callbacks for an isolate are executed one at a time.

[deostroll]

So what guarantees that callbacks in an isolate execute one at a time? Is it libuv?