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- the deadlock recovery thread has been replaced by a parameter to the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- the separate exec lock has been replaced by a lock on the VM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

78 lines
3 KiB
C

#ifndef __VFS_FPROC_H__
#define __VFS_FPROC_H__
#include "threads.h"
#include <sys/select.h>
#include <minix/safecopies.h>
/* This is the per-process information. A slot is reserved for each potential
* process. Thus NR_PROCS must be the same as in the kernel. It is not
* possible or even necessary to tell when a slot is free here.
*/
#define LOCK_DEBUG 0
EXTERN struct fproc {
unsigned fp_flags;
pid_t fp_pid; /* process id */
endpoint_t fp_endpoint; /* kernel endpoint number of this process */
struct vnode *fp_wd; /* working directory; NULL during reboot */
struct vnode *fp_rd; /* root directory; NULL during reboot */
struct filp *fp_filp[OPEN_MAX];/* the file descriptor table */
fd_set fp_filp_inuse; /* which fd's are in use? */
fd_set fp_cloexec_set; /* bit map for POSIX Table 6-2 FD_CLOEXEC */
dev_t fp_tty; /* major/minor of controlling tty */
int fp_blocked_on; /* what is it blocked on */
int fp_block_callnr; /* blocked call if rd/wr can't finish */
int fp_cum_io_partial; /* partial byte count if rd/wr can't finish */
endpoint_t fp_task; /* which task is proc suspended on */
endpoint_t fp_ioproc; /* proc no. in suspended-on i/o message */
cp_grant_id_t fp_grant; /* revoke this grant on unsuspend if > -1 */
uid_t fp_realuid; /* real user id */
uid_t fp_effuid; /* effective user id */
gid_t fp_realgid; /* real group id */
gid_t fp_effgid; /* effective group id */
int fp_ngroups; /* number of supplemental groups */
gid_t fp_sgroups[NGROUPS_MAX];/* supplemental groups */
mode_t fp_umask; /* mask set by umask system call */
mutex_t fp_lock; /* mutex to lock fproc object */
struct worker_thread *fp_worker;/* active worker thread, or NULL */
void (*fp_func)(); /* handler function for pending work */
message fp_msg; /* pending or active message from process */
message fp_pm_msg; /* pending/active postponed PM request */
char fp_name[PROC_NAME_LEN]; /* Last exec() */
#if LOCK_DEBUG
int fp_vp_rdlocks; /* number of read-only locks on vnodes */
int fp_vmnt_rdlocks; /* number of read-only locks on vmnts */
#endif
vir_bytes text_size; /* text segment size of current process */
vir_bytes data_size; /* data segment size of current process */
} fproc[NR_PROCS];
/* fp_flags */
#define FP_NOFLAGS 00
#define FP_SUSP_REOPEN 01 /* Process is suspended until the reopens are
* completed (after the restart of a driver).
*/
#define FP_REVIVED 0002 /* Indicates process is being revived */
#define FP_SESLDR 0004 /* Set if process is session leader */
#define FP_PENDING 0010 /* Set if process has pending work */
#define FP_EXITING 0020 /* Set if process is exiting */
#define FP_PM_WORK 0040 /* Set if process has a postponed PM request */
#define FP_SRV_PROC 0100 /* Set if process is a service */
/* Field values. */
#define NOT_REVIVING 0xC0FFEEE /* process is not being revived */
#define REVIVING 0xDEEAD /* process is being revived from suspension */
#define PID_FREE 0 /* process slot free */
#endif /* __VFS_FPROC_H__ */