summaryrefslogtreecommitdiff
path: root/libpager/data-return.c
blob: ee6c6e83de0cca8930c714fc375a928121a4c768 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
/* Implementation of memory_object_data_return for pager library
   Copyright (C) 1994,95,96,99,2000,02 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */

#include "priv.h"
#include "memory_object_S.h"
#include <stdio.h>
#include <string.h>
#include <assert.h>

/* Worker function used by _pager_seqnos_memory_object_data_return
   and _pager_seqnos_memory_object_data_initialize.  All args are
   as for _pager_seqnos_memory_object_data_return; the additional
   INITIALIZING arg identifies which function is calling us. */
kern_return_t
_pager_do_write_request (struct pager *p,
			 mach_port_seqno_t seqno,
			 mach_port_t control,
			 vm_offset_t offset,
			 pointer_t data,
			 vm_size_t length,
			 int dirty,
			 int kcopy,
			 int initializing)
{
  short *pm_entries;
  int npages, i;
  char *notified;
  error_t *pagerrs;
  struct lock_request *lr;
  struct lock_list {struct lock_request *lr;
		    struct lock_list *next;} *lock_list, *ll;
  int wakeup;
  int omitdata = 0;

  if (!p
      || p->port.class != _pager_class)
    return EOPNOTSUPP;

  /* Acquire the right to meddle with the pagemap */
  pthread_mutex_lock (&p->interlock);
  _pager_wait_for_seqno (p, seqno);

  /* sanity checks -- we don't do multi-page requests yet.  */
  if (control != p->memobjcntl)
    {
      printf ("incg data return: wrong control port\n");
      goto release_out;
    }
  if (length % __vm_page_size)
    {
      printf ("incg data return: bad length size %zd\n", length);
      goto release_out;
    }
  if (offset % __vm_page_size)
    {
      printf ("incg data return: misaligned request\n");
      goto release_out;
    }

  if (p->pager_state != NORMAL)
    {
      printf ("pager in wrong state for write\n");
      goto release_out;
    }

  npages = length / __vm_page_size;
  pagerrs = alloca (npages * sizeof (error_t));

  notified = alloca (npages * (sizeof *notified));
#ifndef NDEBUG
  memset (notified, -1, npages * (sizeof *notified));
#endif

  _pager_block_termination (p);	/* until we are done with the pagemap
				   when the write completes. */

  _pager_pagemap_resize (p, offset + length);

  pm_entries = &p->pagemap[offset / __vm_page_size];

  if (! dirty)
    {
      munmap ((void *) data, length);
      if (!kcopy) {
        /* Prepare notified array.  */
        for (i = 0; i < npages; i++)
          notified[i] = (p->notify_on_evict
                         && ! (pm_entries[i] & PM_PAGEINWAIT));

        _pager_release_seqno (p, seqno);
        goto notify;
      }
      else {
        _pager_allow_termination (p);
        goto release_out;
      }
    }

  /* Make sure there are no other in-progress writes for any of these
     pages before we begin.  This imposes a little more serialization
     than we really have to require (because *all* future writes on
     this object are going to wait for seqno while we wait for the
     previous write), but the case is relatively infrequent.  */
 retry:
  for (i = 0; i < npages; i++)
    if (pm_entries[i] & PM_PAGINGOUT)
      {
	pm_entries[i] |= PM_WRITEWAIT;
	pthread_cond_wait (&p->wakeup, &p->interlock);
	goto retry;
      }

  /* Mark these pages as being paged out.  */
  if (initializing)
    {
      assert (npages <= 32);
      for (i = 0; i < npages; i++)
	{
	  if (pm_entries[i] & PM_INIT)
	    omitdata |= 1 << i;
	  else
	    pm_entries[i] |= PM_PAGINGOUT | PM_INIT;
	}
    }
  else
    for (i = 0; i < npages; i++)
      pm_entries[i] |= PM_PAGINGOUT | PM_INIT;

  /* If this write occurs while a lock is pending, record
     it.  We have to keep this list because a lock request
     might come in while we do the I/O; in that case there
     would be a new entry on p->lock_requests and we must
     make sure we don't decrement it.  So we have to keep
     track independently of which lock requests we incremented. */
  lock_list = 0;
  for (lr = p->lock_requests; lr; lr = lr->next)
    if (offset < lr->end && offset + length >= lr->start)
      {
	ll = alloca (sizeof (struct lock_list));
	ll->lr = lr;
	ll->next = lock_list;
	lock_list = ll;
	lr->pending_writes++;
      }

  /* Let someone else in. */
  _pager_release_seqno (p, seqno);
  pthread_mutex_unlock (&p->interlock);

  /* This is inefficient; we should send all the pages to the device at once
     but until the pager library interface is changed, this will have to do. */

  for (i = 0; i < npages; i++)
    if (!(omitdata & (1 << i)))
      pagerrs[i] = pager_write_page (p->upi,
				     offset + (vm_page_size * i),
				     data + (vm_page_size * i));

  /* Acquire the right to meddle with the pagemap */
  pthread_mutex_lock (&p->interlock);
  _pager_pagemap_resize (p, offset + length);
  pm_entries = &p->pagemap[offset / __vm_page_size];

  wakeup = 0;
  for (i = 0; i < npages; i++)
    {
      if (omitdata & (1 << i))
	{
	  notified[i] = 0;
	  continue;
	}

      if (pm_entries[i] & PM_WRITEWAIT)
	wakeup = 1;

      if (pagerrs[i] && ! (pm_entries[i] & PM_PAGEINWAIT))
	/* The only thing we can do here is mark the page, and give
	   errors from now on when it is to be read.  This is
	   imperfect, because if all users go away, the pagemap will
	   be freed, and this information lost.  Oh well.  It's still
	   better than Un*x.  Of course, if we are about to hand this
	   data to the kernel, the error isn't a problem, hence the
	   check for pageinwait.  */
	pm_entries[i] |= PM_INVALID;

      if (pm_entries[i] & PM_PAGEINWAIT)
	{
	  memory_object_data_supply (p->memobjcntl,
				     offset + (vm_page_size * i),
				     data + (vm_page_size * i),
				     vm_page_size, 1,
				     VM_PROT_NONE, 0, MACH_PORT_NULL);
	  notified[i] = 0;
	}
      else
	{
	  munmap ((void *) (data + (vm_page_size * i)),
		  vm_page_size);
	  notified[i] = (! kcopy && p->notify_on_evict);
	  if (! kcopy)
	    pm_entries[i] &= ~PM_INCORE;
	}

      pm_entries[i] &= ~(PM_PAGINGOUT | PM_PAGEINWAIT | PM_WRITEWAIT);
    }

  for (ll = lock_list; ll; ll = ll->next)
    if (!--ll->lr->pending_writes && !ll->lr->locks_pending)
      wakeup = 1;

  if (wakeup)
    pthread_cond_broadcast (&p->wakeup);

 notify:
  _pager_allow_termination (p);
  pthread_mutex_unlock (&p->interlock);

  for (i = 0; i < npages; i++)
    {
      assert (notified[i] == 0 || notified[i] == 1);
      if (notified[i])
	{
	  short *pm_entry = &pm_entries[i];

	  /* Do notify user.  */
	  pager_notify_evict (p->upi, offset + (i * vm_page_size));

	  /* Clear any error that is left.  Notification on eviction
	     is used only to change association of page, so any
	     error may no longer be valid.  */
	  pthread_mutex_lock (&p->interlock);
	  *pm_entry = SET_PM_ERROR (SET_PM_NEXTERROR (*pm_entry, 0), 0);
	  pthread_mutex_unlock (&p->interlock);
	}
    }

  return 0;

 release_out:
  _pager_release_seqno (p, seqno);
  pthread_mutex_unlock (&p->interlock);
  return 0;
}

/* Implement pageout call back as described by <mach/memory_object.defs>. */
kern_return_t
_pager_seqnos_memory_object_data_return (struct pager *p,
					 mach_port_seqno_t seqno,
					 mach_port_t control,
					 vm_offset_t offset,
					 pointer_t data,
					 vm_size_t length,
					 int dirty,
					 int kcopy)
{
  return _pager_do_write_request (p, seqno, control, offset, data,
				  length, dirty, kcopy, 0);
}