minix/servers/vfs/threads.h
David van Moolenbroek 723e51327f VFS: worker thread model overhaul
The main purpose of this patch is to fix handling of unpause calls
from PM while another call is ongoing. The solution to this problem
sparked a full revision of the threading model, consisting of a large
number of related changes:

- all active worker threads are now always associated with a process,
  and every process has at most one active thread working for it;
- the process lock is always held by a process's worker thread;
- a process can now have both normal work and postponed PM work
  associated to it;
- timer expiry and non-postponed PM work is done from the main thread;
- filp garbage collection is done from a thread associated with VFS;
- reboot calls from PM are now done from a thread associated with PM;
- the DS events handler is protected from starting multiple threads;
- support for a system worker thread has been removed;
- the deadlock recovery thread has been replaced by a parameter to the
  worker_start() function; the number of worker threads has
  consequently been increased by one;
- saving and restoring of global but per-thread variables is now
  centralized in worker_suspend() and worker_resume(); err_code is now
  saved and restored in all cases;
- the concept of jobs has been removed, and job_m_in now points to a
  message stored in the worker thread structure instead;
- the PM lock has been removed;
- the separate exec lock has been replaced by a lock on the VM
  process, which was already being locked for exec calls anyway;
- PM_UNPAUSE is now processed as a postponed PM request, from a thread
  associated with the target process;
- the FP_DROP_WORK flag has been removed, since it is no longer more
  than just an optimization and only applied to processes operating on
  a pipe when getting killed;
- assignment to "fp" now takes place only when obtaining new work in
  the main thread or a worker thread, when resuming execution of a
  thread, and in the special case of exiting processes during reboot;
- there are no longer special cases where the yield() call is used to
  force a thread to run.

Change-Id: I7a97b9b95c2450454a9b5318dfa0e6150d4e6858
2014-02-18 11:25:03 +01:00

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966 B
C

#ifndef __VFS_WORKERS_H__
#define __VFS_WORKERS_H__
#include <minix/mthread.h>
#define thread_t mthread_thread_t
#define mutex_t mthread_mutex_t
#define cond_t mthread_cond_t
#define attr_t mthread_attr_t
#define threads_init mthread_init
#define yield mthread_yield
#define yield_all mthread_yield_all
#define mutex_init mthread_mutex_init
#define mutex_destroy mthread_mutex_destroy
#define mutex_lock mthread_mutex_lock
#define mutex_trylock mthread_mutex_trylock
#define mutex_unlock mthread_mutex_unlock
#define cond_init mthread_cond_init
#define cond_destroy mthread_cond_destroy
#define cond_wait mthread_cond_wait
#define cond_signal mthread_cond_signal
struct fproc;
struct worker_thread {
thread_t w_tid;
mutex_t w_event_mutex;
cond_t w_event;
struct fproc *w_fp;
message w_msg;
int w_err_code;
message *w_fs_sendrec;
message *w_drv_sendrec;
endpoint_t w_task;
struct dmap *w_dmap;
struct worker_thread *w_next;
};
#endif