CODEWITHSUNDEEP
linuxlinux-kernel
J Fritsch
J Fritsch

Reputation: 3358

Where can I find documentation on the kflushd?

I cannot find any documentation on the kflushd such as what it does exactly, how it is involved in network IO and how I could use it/call it from my own code.

Upvotes: 1

Views: 841

Answers (2)

Basile Starynkevitch
Basile Starynkevitch

Reputation: 1

Kernel processes like kflushd are started by the kernel on its own (they are not descendant of the init process started by fork-ing) and exist only for the kernel needs. User applications may invisibly need them (because they need some feature offered by the kernel which the kernel implements with the help of its own kernel processes) but don't actively use them.

You definitely should use appropriately the fflush(3) library function (which just happens to make the relevant write(2) syscalls).

You may want to use the fsync(2) and related syscalls.

Regarding networking, you may be interested by Nagle's algorithm. See this answer.

Upvotes: 1

Jesus Ramos
Jesus Ramos

Reputation: 23266

kflushd AFAIK handles writing out pending I/O in memory to their corresponding devices. If you want to flush pending I/O's you can always call flush, fflush, or sync to force a write to the I/O device.

To call it from your code simply use one of the calls I mentioned (although I think there might be one more I'm forgetting).

Upvotes: 2

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