Introduction

The openMosix HOWTO:
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# 18.1. Introduction

this part has been written by Amit Shah

There's not much documentation available right now for the kernel. I hope to write some in the coming weeks. Anyways, here's how the sources are laid out:

The openMosix code resides largely in hpc/ and include/hpc. There are lots of patches to the core kernel files everywhere, right from the arch/i386 directories to mm/, fs/, etc. You need to read up the code which interests you and think that would matter for the present situation (that shouldn't be a problem, since you've done kernel coding).

here's what you should expect in each of the source files:

- hpc/badops.c: one file to handle all the bad operations: mostly return err codes

- hpc/balance.c: The load balancer code (load + mem usage + n/w usage)

- hpc/comm.c: The intra-cluster communication setup

- hpc/config.c: The config code for openMosix: after you run the startup script

- hpc/decay.c: decay (age) the stats and info collected from other nodes

- hpc/deputy.c: Code executed on the deputy: service remote syscalls (ie. after the process has migrated), signals, etc.

- hpc/dfsa.c: Direct File System Access code: the distributed file system abstraction layer

- hpc/div.c: the algorithms to do floating point divisions

- hpc/export.c: export symbols needed in other files

- hpc/freemem.c: to keep track of free, avl. memory and to free it if need be. hugely taken from the Linux mm/ code.

- hpc/hpcadmin.c: tune openMosix admin values (through /proc/hpc)

- hpc/hpcproc.c: The /proc/hpc code is handled here

- hpc/info.c: The info daemon: sends and receives (multicast) load+mem usage stats throughout the cluster

- hpc/init.c: Initialization code: initializes the daemons, etc.

- hpc/kernel.c: most of the "core" code: all the important algorithms, decisions, etc. made here.

- hpc/load.c: calculation of local load, etc.

- hpc/mig.c: Code that handles the migration. Code in this file is invoked on any migration: deputy->remote, remote->deputy; remote->remote

- hpc/prequest.c: handles the process's requests: signals, more memory, etc.

- hpc/remote.c: Code executed when the process is on the remote: syscalls handling on remote, passing control to deputy, etc.

- hpc/rinode.c: fs/ related stuff: used mostly for DFSA

- hpc/service.c: setting up daemons, getting memory, etc.

- hpc/syscalls.c: handles all the remote syscalls here

- hpc/ucache.c: handles the ucache: mostly mm/, fs/ stuff.

the other files like auto_syscalls.c, alternate.c are generated at compile time.

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