minix/servers/vfs/const.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- the deadlock recovery thread has been replaced by a parameter to the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- the separate exec lock has been replaced by a lock on the VM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

47 lines
1.8 KiB
C

#ifndef __VFS_CONST_H__
#define __VFS_CONST_H__
/* Tables sizes */
#define NR_FILPS 1024 /* # slots in filp table */
#define NR_LOCKS 8 /* # slots in the file locking table */
#define NR_MNTS 16 /* # slots in mount table */
#define NR_VNODES 1024 /* # slots in vnode table */
#define NR_WTHREADS 9 /* # slots in worker thread table */
#define NR_NONEDEVS NR_MNTS /* # slots in nonedev bitmap */
/* Miscellaneous constants */
#define SU_UID ((uid_t) 0) /* super_user's uid_t */
#define SYS_UID ((uid_t) 0) /* uid_t for system processes and INIT */
#define SYS_GID ((gid_t) 0) /* gid_t for system processes and INIT */
#define FP_BLOCKED_ON_NONE 0 /* not blocked */
#define FP_BLOCKED_ON_PIPE 1 /* susp'd on pipe */
#define FP_BLOCKED_ON_LOCK 2 /* susp'd on lock */
#define FP_BLOCKED_ON_POPEN 3 /* susp'd on pipe open */
#define FP_BLOCKED_ON_SELECT 4 /* susp'd on select */
#define FP_BLOCKED_ON_OTHER 5 /* blocked on other process, check
fp_task to find out */
/* test if the process is blocked on something */
#define fp_is_blocked(fp) ((fp)->fp_blocked_on != FP_BLOCKED_ON_NONE)
/* test if reply is a driver reply */
#define IS_DRV_REPLY(x) (IS_DEV_RS(x) || IS_BDEV_RS(x))
#define DUP_MASK 0100 /* mask to distinguish dup2 from dup */
#define LOOK_UP 0 /* tells search_dir to lookup string */
#define ENTER 1 /* tells search_dir to make dir entry */
#define DELETE 2 /* tells search_dir to delete entry */
#define IS_EMPTY 3 /* tells search_dir to ret. OK or ENOTEMPTY */
#define SYMLOOP 16
#define LABEL_MAX 16 /* maximum label size (including '\0'). Should
* not be smaller than 16 or bigger than
* M3_LONG_STRING.
*/
#define FSTYPE_MAX VFS_NAMELEN /* maximum file system type size */
#endif