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minix/servers/pm/misc.c
Tomas Hruby b4cf88a04f Userspace scheduling 
- cotributed by Bjorn Swift

- In this first phase, scheduling is moved from the kernel to the PM
  server. The next steps are to a) moving scheduling to its own server
  and b) include useful information in the "out of quantum" message,
  so that the scheduler can make use of this information.

- The kernel process table now keeps record of who is responsible for
  scheduling each process (p_scheduler). When this pointer is NULL,
  the process will be scheduled by the kernel. If such a process runs
  out of quantum, the kernel will simply renew its quantum an requeue
  it.

- When PM loads, it will take over scheduling of all running
  processes, except system processes, using sys_schedctl().
  Essentially, this only results in taking over init. As children
  inherit a scheduler from their parent, user space programs forked by
  init will inherit PM (for now) as their scheduler.

 - Once a process has been assigned a scheduler, and runs out of
   quantum, its RTS_NO_QUANTUM flag will be set and the process
   dequeued. The kernel will send a message to the scheduler, on the
   process' behalf, informing the scheduler that it has run out of
   quantum. The scheduler can take what ever action it pleases, based
   on its policy, and then reschedule the process using the
   sys_schedule() system call.

- Balance queues does not work as before. While the old in-kernel
  function used to renew the quantum of processes in the highest
  priority run queue, the user-space implementation only acts on
  processes that have been bumped down to a lower priority queue.
  This approach reacts slower to changes than the old one, but saves
  us sending a sys_schedule message for each process every time we
  balance the queues. Currently, when processes are moved up a
  priority queue, their quantum is also renewed, but this can be
  fiddled with.

- do_nice has been removed from kernel. PM answers to get- and
  setpriority calls, updates it's own nice variable as well as the
  max_run_queue. This will be refactored once scheduling is moved to a
  separate server. We will probably have PM update it's local nice
  value and then send a message to whoever is scheduling the process.

- changes to fix an issue in do_fork() where processes could run out
  of quantum but bypassing the code path that handles it correctly.
  The future plan is to remove the policy from do_fork() and implement
  it in userspace too.
2010-03-29 11:07:20 +00:00

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/* Miscellaneous system calls. Author: Kees J. Bot
* 31 Mar 2000
* The entry points into this file are:
* do_reboot: kill all processes, then reboot system
* do_procstat: request process status (Jorrit N. Herder)
* do_getsysinfo: request copy of PM data structure (Jorrit N. Herder)
* do_getprocnr: lookup process slot number (Jorrit N. Herder)
* do_getepinfo: get the pid/uid/gid of a process given its endpoint
* do_getsetpriority: get/set process priority
* do_svrctl: process manager control
*/
#define brk _brk
#include "pm.h"
#include <minix/callnr.h>
#include <signal.h>
#include <sys/svrctl.h>
#include <sys/resource.h>
#include <sys/utsname.h>
#include <minix/com.h>
#include <minix/config.h>
#include <minix/sysinfo.h>
#include <minix/type.h>
#include <minix/vm.h>
#include <string.h>
#include <machine/archtypes.h>
#include <lib.h>
#include <assert.h>
#include "mproc.h"
#include "param.h"
#include "../../kernel/proc.h"
PUBLIC struct utsname uts_val = {
"Minix", /* system name */
"noname", /* node/network name */
OS_RELEASE, /* O.S. release (e.g. 1.5) */
OS_VERSION, /* O.S. version (e.g. 10) */
"xyzzy", /* machine (cpu) type (filled in later) */
#if __i386
"i386", /* architecture */
#else
#error /* oops, no 'uname -mk' */
#endif
};
PRIVATE char *uts_tbl[] = {
uts_val.arch,
NULL, /* No kernel architecture */
uts_val.machine,
NULL, /* No hostname */
uts_val.nodename,
uts_val.release,
uts_val.version,
uts_val.sysname,
NULL, /* No bus */ /* No bus */
};
#if ENABLE_SYSCALL_STATS
PUBLIC unsigned long calls_stats[NCALLS];
#endif
FORWARD _PROTOTYPE( int getpciinfo, (struct pciinfo *pciinfo) );
/*===========================================================================*
* do_procstat *
*===========================================================================*/
PUBLIC int do_procstat()
{
/* For the moment, this is only used to return pending signals to
* system processes that request the PM for their own status.
*
* Future use might include the FS requesting for process status of
* any user process.
*/
/* This call should be removed, or made more general. */
if (m_in.stat_nr == SELF) {
mp->mp_reply.sig_set = mp->mp_sigpending;
sigemptyset(&mp->mp_sigpending);
}
else {
return(ENOSYS);
}
return(OK);
}
/*===========================================================================*
* do_sysuname *
*===========================================================================*/
PUBLIC int do_sysuname()
{
/* Set or get uname strings. */
int r;
size_t n;
char *string;
#if 0 /* for updates */
char tmp[sizeof(uts_val.nodename)];
static short sizes[] = {
0, /* arch, (0 = read-only) */
0, /* kernel */
0, /* machine */
0, /* sizeof(uts_val.hostname), */
sizeof(uts_val.nodename),
0, /* release */
0, /* version */
0, /* sysname */
};
#endif
if ((unsigned) m_in.sysuname_field >= _UTS_MAX) return(EINVAL);
string = uts_tbl[m_in.sysuname_field];
if (string == NULL)
return EINVAL; /* Unsupported field */
switch (m_in.sysuname_req) {
case _UTS_GET:
/* Copy an uname string to the user. */
n = strlen(string) + 1;
if (n > m_in.sysuname_len) n = m_in.sysuname_len;
r = sys_vircopy(SELF, D, (phys_bytes) string,
mp->mp_endpoint, D, (phys_bytes) m_in.sysuname_value,
(phys_bytes) n);
if (r < 0) return(r);
break;
#if 0 /* no updates yet */
case _UTS_SET:
/* Set an uname string, needs root power. */
len = sizes[m_in.sysuname_field];
if (mp->mp_effuid != 0 || len == 0) return(EPERM);
n = len < m_in.sysuname_len ? len : m_in.sysuname_len;
if (n <= 0) return(EINVAL);
r = sys_vircopy(mp->mp_endpoint, D, (phys_bytes) m_in.sysuname_value,
SELF, D, (phys_bytes) tmp, (phys_bytes) n);
if (r < 0) return(r);
tmp[n-1] = 0;
strcpy(string, tmp);
break;
#endif
default:
return(EINVAL);
}
/* Return the number of bytes moved. */
return(n);
}
/*===========================================================================*
* do_getsysinfo *
*===========================================================================*/
PUBLIC int do_getsysinfo()
{
struct mproc *proc_addr;
vir_bytes src_addr, dst_addr;
struct kinfo kinfo;
struct loadinfo loadinfo;
struct pciinfo pciinfo;
static struct proc proctab[NR_PROCS+NR_TASKS];
size_t len;
int s, r;
/* This call leaks important information (the contents of registers). */
if (mp->mp_effuid != 0)
{
printf("PM: unauthorized call of do_getsysinfo by proc %d '%s'\n",
mp->mp_endpoint, mp->mp_name);
sys_sysctl_stacktrace(mp->mp_endpoint);
return EPERM;
}
switch(m_in.info_what) {
case SI_KINFO: /* kernel info is obtained via PM */
sys_getkinfo(&kinfo);
src_addr = (vir_bytes) &kinfo;
len = sizeof(struct kinfo);
break;
case SI_PROC_ADDR: /* get address of PM process table */
proc_addr = &mproc[0];
src_addr = (vir_bytes) &proc_addr;
len = sizeof(struct mproc *);
break;
case SI_PROC_TAB: /* copy entire process table */
src_addr = (vir_bytes) mproc;
len = sizeof(struct mproc) * NR_PROCS;
break;
case SI_KPROC_TAB: /* copy entire process table */
if((r=sys_getproctab(proctab)) != OK)
return r;
src_addr = (vir_bytes) proctab;
len = sizeof(proctab);
break;
case SI_LOADINFO: /* loadinfo is obtained via PM */
sys_getloadinfo(&loadinfo);
src_addr = (vir_bytes) &loadinfo;
len = sizeof(struct loadinfo);
break;
case SI_PCI_INFO: /* PCI info is obtained via PM */
if ((r=getpciinfo(&pciinfo)) != OK)
return r;
src_addr = (vir_bytes) &pciinfo;
len = sizeof(struct pciinfo);
break;
#if ENABLE_SYSCALL_STATS
case SI_CALL_STATS:
src_addr = (vir_bytes) calls_stats;
len = sizeof(calls_stats);
break;
#endif
default:
return(EINVAL);
}
dst_addr = (vir_bytes) m_in.info_where;
if (OK != (s=sys_datacopy(SELF, src_addr, who_e, dst_addr, len)))
return(s);
return(OK);
}
/*===========================================================================*
* do_getsysinfo_up *
*===========================================================================*/
PUBLIC int do_getsysinfo_up()
{
vir_bytes src_addr, dst_addr;
struct loadinfo loadinfo;
size_t len, real_len;
u64_t idle_tsc;
int s;
switch(m_in.SIU_WHAT) {
case SIU_LOADINFO: /* loadinfo is obtained via PM */
if ((s = sys_getloadinfo(&loadinfo)) != OK)
return s;
src_addr = (vir_bytes) &loadinfo;
real_len = sizeof(struct loadinfo);
break;
case SIU_SYSTEMHZ:
src_addr = (vir_bytes) &system_hz;
real_len = sizeof(system_hz);
break;
case SIU_IDLETSC:
if ((s = sys_getidletsc(&idle_tsc)) != OK)
return s;
src_addr = (vir_bytes) &idle_tsc;
real_len = sizeof(idle_tsc);
break;
default:
return(EINVAL);
}
/* Let application know what the length was. */
len = real_len;
if(len > m_in.SIU_LEN)
len = m_in.SIU_LEN;
dst_addr = (vir_bytes) m_in.SIU_WHERE;
if (OK != (s=sys_datacopy(SELF, src_addr, who_e, dst_addr, len)))
return(s);
return(real_len);
}
/*===========================================================================*
* do_getprocnr *
*===========================================================================*/
PUBLIC int do_getprocnr()
{
register struct mproc *rmp;
static char search_key[PROC_NAME_LEN+1];
int key_len;
int s;
/* This call should be moved to DS. */
if (mp->mp_effuid != 0)
{
/* For now, allow non-root processes to request their own endpoint. */
if (m_in.pid < 0 && m_in.namelen == 0) {
mp->mp_reply.PM_ENDPT = who_e;
mp->mp_reply.PM_PENDPT = NONE;
return OK;
}
printf("PM: unauthorized call of do_getprocnr by proc %d\n",
mp->mp_endpoint);
sys_sysctl_stacktrace(mp->mp_endpoint);
return EPERM;
}
#if 0
printf("PM: do_getprocnr(%d) call from endpoint %d, %s\n",
m_in.pid, mp->mp_endpoint, mp->mp_name);
#endif
if (m_in.pid >= 0) { /* lookup process by pid */
if ((rmp = find_proc(m_in.pid)) != NIL_MPROC) {
mp->mp_reply.PM_ENDPT = rmp->mp_endpoint;
#if 0
printf("PM: pid result: %d\n", rmp->mp_endpoint);
#endif
return(OK);
}
return(ESRCH);
} else if (m_in.namelen > 0) { /* lookup process by name */
key_len = MIN(m_in.namelen, PROC_NAME_LEN);
if (OK != (s=sys_datacopy(who_e, (vir_bytes) m_in.PMBRK_ADDR,
SELF, (vir_bytes) search_key, key_len)))
return(s);
search_key[key_len] = '\0'; /* terminate for safety */
for (rmp = &mproc[0]; rmp < &mproc[NR_PROCS]; rmp++) {
if (((rmp->mp_flags & (IN_USE | EXITING)) == IN_USE) &&
strncmp(rmp->mp_name, search_key, key_len)==0) {
mp->mp_reply.PM_ENDPT = rmp->mp_endpoint;
return(OK);
}
}
return(ESRCH);
} else { /* return own/parent process number */
#if 0
printf("PM: endpt result: %d\n", mp->mp_reply.PM_ENDPT);
#endif
mp->mp_reply.PM_ENDPT = who_e;
mp->mp_reply.PM_PENDPT = mproc[mp->mp_parent].mp_endpoint;
}
return(OK);
}
/*===========================================================================*
* do_getepinfo *
*===========================================================================*/
PUBLIC int do_getepinfo()
{
register struct mproc *rmp;
endpoint_t ep;
/* This call should be moved to DS. */
if (mp->mp_effuid != 0)
{
printf("PM: unauthorized call of do_getepinfo by proc %d\n",
mp->mp_endpoint);
sys_sysctl_stacktrace(mp->mp_endpoint);
return EPERM;
}
ep= m_in.PM_ENDPT;
for (rmp = &mproc[0]; rmp < &mproc[NR_PROCS]; rmp++) {
if ((rmp->mp_flags & IN_USE) && (rmp->mp_endpoint == ep)) {
mp->mp_reply.reply_res2 = rmp->mp_effuid;
mp->mp_reply.reply_res3 = rmp->mp_effgid;
return(rmp->mp_pid);
}
}
/* Process not found */
return(ESRCH);
}
/*===========================================================================*
* do_reboot *
*===========================================================================*/
PUBLIC int do_reboot()
{
message m;
int r;
/* Check permission to abort the system. */
if (mp->mp_effuid != SUPER_USER) return(EPERM);
/* See how the system should be aborted. */
abort_flag = (unsigned) m_in.reboot_flag;
if (abort_flag >= RBT_INVALID) return(EINVAL);
if (RBT_MONITOR == abort_flag) {
int r;
if(m_in.reboot_strlen >= sizeof(monitor_code))
return EINVAL;
if((r = sys_datacopy(who_e, (vir_bytes) m_in.reboot_code,
SELF, (vir_bytes) monitor_code, m_in.reboot_strlen)) != OK)
return r;
monitor_code[m_in.reboot_strlen] = '\0';
}
else
monitor_code[0] = '\0';
/* Order matters here. When FS is told to reboot, it exits all its
* processes, and then would be confused if they're exited again by
* SIGKILL. So first kill, then reboot.
*/
check_sig(-1, SIGKILL, FALSE /* ksig*/); /* kill all users except init */
sys_stop(INIT_PROC_NR); /* stop init, but keep it around */
/* Tell FS to reboot */
m.m_type = PM_REBOOT;
tell_fs(&mproc[FS_PROC_NR], &m);
return(SUSPEND); /* don't reply to caller */
}
/*===========================================================================*
* do_getsetpriority *
*===========================================================================*/
PUBLIC int do_getsetpriority()
{
int r, arg_which, arg_who, arg_pri, new_q;
struct mproc *rmp;
arg_which = m_in.m1_i1;
arg_who = m_in.m1_i2;
arg_pri = m_in.m1_i3; /* for SETPRIORITY */
/* Code common to GETPRIORITY and SETPRIORITY. */
/* Only support PRIO_PROCESS for now. */
if (arg_which != PRIO_PROCESS)
return(EINVAL);
if (arg_who == 0)
rmp = mp;
else
if ((rmp = find_proc(arg_who)) == NIL_MPROC)
return(ESRCH);
if (mp->mp_effuid != SUPER_USER &&
mp->mp_effuid != rmp->mp_effuid && mp->mp_effuid != rmp->mp_realuid)
return EPERM;
/* If GET, that's it. */
if (call_nr == GETPRIORITY) {
return(rmp->mp_nice - PRIO_MIN);
}
/* Only root is allowed to reduce the nice level. */
if (rmp->mp_nice > arg_pri && mp->mp_effuid != SUPER_USER)
return(EACCES);
/* We're SET, and it's allowed.
*
* The value passed in is currently between PRIO_MIN and PRIO_MAX.
* We have to scale this between MIN_USER_Q and MAX_USER_Q to match
* the kernel's scheduling queues.
*
* TODO: This assumes that we are the scheduler, this will be changed
* once the scheduler gets factored out of PM to its own server
*/
if (arg_pri < PRIO_MIN || arg_pri > PRIO_MAX) return(EINVAL);
new_q = MAX_USER_Q + (arg_pri-PRIO_MIN) * (MIN_USER_Q-MAX_USER_Q+1) /
(PRIO_MAX-PRIO_MIN+1);
if (new_q < MAX_USER_Q) new_q = MAX_USER_Q; /* shouldn't happen */
if (new_q > MIN_USER_Q) new_q = MIN_USER_Q; /* shouldn't happen */
rmp->mp_max_priority = rmp->mp_priority = new_q;
if ((r = sys_schedule(rmp->mp_priority, rmp->mp_priority,
rmp->mp_time_slice)) != OK)
return(r);
rmp->mp_nice = arg_pri;
return(OK);
}
/*===========================================================================*
* do_svrctl *
*===========================================================================*/
PUBLIC int do_svrctl()
{
int s, req;
vir_bytes ptr;
#define MAX_LOCAL_PARAMS 2
static struct {
char name[30];
char value[30];
} local_param_overrides[MAX_LOCAL_PARAMS];
static int local_params = 0;
req = m_in.svrctl_req;
ptr = (vir_bytes) m_in.svrctl_argp;
/* Is the request indeed for the MM? */
if (((req >> 8) & 0xFF) != 'M') return(EINVAL);
/* Control operations local to the PM. */
switch(req) {
case MMSETPARAM:
case MMGETPARAM: {
struct sysgetenv sysgetenv;
char search_key[64];
char *val_start;
size_t val_len;
size_t copy_len;
/* Copy sysgetenv structure to PM. */
if (sys_datacopy(who_e, ptr, SELF, (vir_bytes) &sysgetenv,
sizeof(sysgetenv)) != OK) return(EFAULT);
/* Set a param override? */
if (req == MMSETPARAM) {
if (local_params >= MAX_LOCAL_PARAMS) return ENOSPC;
if (sysgetenv.keylen <= 0
|| sysgetenv.keylen >=
sizeof(local_param_overrides[local_params].name)
|| sysgetenv.vallen <= 0
|| sysgetenv.vallen >=
sizeof(local_param_overrides[local_params].value))
return EINVAL;
if ((s = sys_datacopy(who_e, (vir_bytes) sysgetenv.key,
SELF, (vir_bytes) local_param_overrides[local_params].name,
sysgetenv.keylen)) != OK)
return s;
if ((s = sys_datacopy(who_e, (vir_bytes) sysgetenv.val,
SELF, (vir_bytes) local_param_overrides[local_params].value,
sysgetenv.vallen)) != OK)
return s;
local_param_overrides[local_params].name[sysgetenv.keylen] = '\0';
local_param_overrides[local_params].value[sysgetenv.vallen] = '\0';
local_params++;
return OK;
}
if (sysgetenv.keylen == 0) { /* copy all parameters */
val_start = monitor_params;
val_len = sizeof(monitor_params);
}
else { /* lookup value for key */
int p;
/* Try to get a copy of the requested key. */
if (sysgetenv.keylen > sizeof(search_key)) return(EINVAL);
if ((s = sys_datacopy(who_e, (vir_bytes) sysgetenv.key,
SELF, (vir_bytes) search_key, sysgetenv.keylen)) != OK)
return(s);
/* Make sure key is null-terminated and lookup value.
* First check local overrides.
*/
search_key[sysgetenv.keylen-1]= '\0';
for(p = 0; p < local_params; p++) {
if (!strcmp(search_key, local_param_overrides[p].name)) {
val_start = local_param_overrides[p].value;
break;
}
}
if (p >= local_params && (val_start = find_param(search_key)) == NULL)
return(ESRCH);
val_len = strlen(val_start) + 1;
}
/* See if it fits in the client's buffer. */
if (val_len > sysgetenv.vallen)
return E2BIG;
/* Value found, make the actual copy (as far as possible). */
copy_len = MIN(val_len, sysgetenv.vallen);
if ((s=sys_datacopy(SELF, (vir_bytes) val_start,
who_e, (vir_bytes) sysgetenv.val, copy_len)) != OK)
return(s);
return OK;
}
default:
return(EINVAL);
}
}
/*===========================================================================*
* _brk *
*===========================================================================*/
extern char *_brksize;
PUBLIC int brk(brk_addr)
char *brk_addr;
{
int r;
/* PM wants to call brk() itself. */
if((r=vm_brk(PM_PROC_NR, brk_addr)) != OK) {
#if 0
printf("PM: own brk(%p) failed: vm_brk() returned %d\n",
brk_addr, r);
#endif
return -1;
}
_brksize = brk_addr;
return 0;
}
/*===========================================================================*
* getpciinfo *
*===========================================================================*/
PRIVATE int getpciinfo(pciinfo)
struct pciinfo *pciinfo;
{
int devind, r;
struct pciinfo_entry *entry;
char *name;
u16_t vid, did;
/* look up PCI process number */
pci_init();
/* start enumerating devices */
entry = pciinfo->pi_entries;
r = pci_first_dev(&devind, &vid, &did);
while (r)
{
/* fetch device name */
name = pci_dev_name(vid, did);
if (!name)
name = "";
/* store device information in table */
assert((char *) entry < (char *) (pciinfo + 1));
entry->pie_vid = vid;
entry->pie_did = did;
strncpy(entry->pie_name, name, sizeof(entry->pie_name));
entry->pie_name[sizeof(entry->pie_name) - 1] = 0;
entry++;
/* continue with the next device */
r = pci_next_dev(&devind, &vid, &did);
}
/* store number of entries */
pciinfo->pi_count = entry - pciinfo->pi_entries;
return OK;
}
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