2000-07-25 Thomas Bushnell, BSG <tb@mit.edu>

	* priv.h (PM_WRITEWAIT): New pagemap bit.
	* data-return.c (_pager_do_write_request): Don't proceed with a
	pageout if one is already in progress.  Once we finish, wake up
	any potential PM_WRITEWAIT waiters.

	* priv.h (PM_INIT): Provide value again.
	* data-return.c (_pager_do_write_request): Track PM_INIT again.

	* priv.h (struct pager): Make pagemap consist of 16-bit elements
	instead of only 8 bits.
	* data-request.c (_pager_seqnos_memory_object_data_request):
	Make PM_ENTRY a short pointer.
	* data-return.c (_pager_do_write_request): Make PM_ENTRIES a short
	pointer.
	* lock-object.c (_pager_lock_object): Make PM_ENTRIES a short
	pointer.
	* mark-error.c (_pager_mark_next_request_error): Make P a short
	pointer.
	(_pager_mark_object_error): Likewise.
	* offer-page.c (pager_offer_page): Make PM_ENTRY a short pointer.
	* object-terminate.c (_pager_free_structure): Interpret
	pagemapsize correctly.
	* pagemap.c (_pager_pagemap_resize): Likewise.

9 files changed, 73 insertions, 31 deletions

diff --git a/libpager/ChangeLog b/libpager/ChangeLog
index 1b0e6a74..1ee91890 100644
--- a/libpager/ChangeLog
+++ b/libpager/ChangeLog
@@ -1,3 +1,29 @@
+2000-07-25  Thomas Bushnell, BSG  <tb@mit.edu>
+
+	* priv.h (PM_WRITEWAIT): New pagemap bit.
+	* data-return.c (_pager_do_write_request): Don't proceed with a
+	pageout if one is already in progress.  Once we finish, wake up
+	any potential PM_WRITEWAIT waiters.
+
+	* priv.h (PM_INIT): Provide value again.
+	* data-return.c (_pager_do_write_request): Track PM_INIT again.
+
+	* priv.h (struct pager): Make pagemap consist of 16-bit elements
+	instead of only 8 bits.
+	* data-request.c (_pager_seqnos_memory_object_data_request):
+	Make PM_ENTRY a short pointer.
+	* data-return.c (_pager_do_write_request): Make PM_ENTRIES a short
+	pointer.	
+	* lock-object.c (_pager_lock_object): Make PM_ENTRIES a short
+	pointer. 
+	* mark-error.c (_pager_mark_next_request_error): Make P a short
+	pointer.  
+	(_pager_mark_object_error): Likewise.
+	* offer-page.c (pager_offer_page): Make PM_ENTRY a short pointer.
+	* object-terminate.c (_pager_free_structure): Interpret
+	pagemapsize correctly.
+	* pagemap.c (_pager_pagemap_resize): Likewise.
+
 2000-01-24  Roland McGrath  <roland@baalperazim.frob.com>
 
 	* pager-memcpy.c (pager_memcpy): Short-circuit return for zero size.
diff --git a/libpager/data-request.c b/libpager/data-request.c
index 0c6d1625..95ec6d27 100644
--- a/libpager/data-request.c
+++ b/libpager/data-request.c
@@ -1,5 +1,5 @@
 /* Implementation of memory_object_data_request for pager library
-   Copyright (C) 1994, 1995, 1996, 1997 Free Software Foundation
+   Copyright (C) 1994, 1995, 1996, 1997, 2000 Free Software Foundation
 
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
@@ -30,7 +30,7 @@ _pager_seqnos_memory_object_data_request (mach_port_t object,
 					  vm_prot_t access)
 {
   struct pager *p;
-  char *pm_entry;
+  short *pm_entry;
   int doread, doerror;
   error_t err;
   vm_address_t page;
diff --git a/libpager/data-return.c b/libpager/data-return.c
index 9f107793..a83026fc 100644
--- a/libpager/data-return.c
+++ b/libpager/data-return.c
@@ -1,5 +1,5 @@
 /* Implementation of memory_object_data_return for pager library
-   Copyright (C) 1994, 1995, 1996, 1999 Free Software Foundation
+   Copyright (C) 1994, 1995, 1996, 1999, 2000 Free Software Foundation
 
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
@@ -37,7 +37,7 @@ _pager_do_write_request (mach_port_t object,
 			 int initializing)
 {
   struct pager *p;
-  char *pm_entries;
+  short *pm_entries;
   int npages, i;
   error_t *pagerrs;
   struct lock_request *lr;
@@ -90,8 +90,21 @@ _pager_do_write_request (mach_port_t object,
 
   pm_entries = &p->pagemap[offset / __vm_page_size];
 
+  /* 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;
+	condition_wait (&p->wakeup, &p->interlock);
+	goto retry;
+      }
+  
   /* Mark these pages as being paged out.  */
-#if 0
   if (initializing)
     {
       assert (npages <= 32);
@@ -106,13 +119,10 @@ _pager_do_write_request (mach_port_t object,
   else
     for (i = 0; i < npages; i++)
       pm_entries[i] |= PM_PAGINGOUT | PM_INIT;
-#else
-  for (i = 0; i < npages; i++)
-    pm_entries[i] |= PM_PAGINGOUT;
+
   if (!kcopy)
     for (i = 0; i < npages; i++)
       pm_entries[i] &= ~PM_INCORE;
-#endif
 
   /* If this write occurs while a lock is pending, record
      it.  We have to keep this list because a lock request
@@ -149,11 +159,15 @@ _pager_do_write_request (mach_port_t object,
   _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))
 	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
@@ -174,13 +188,13 @@ _pager_do_write_request (mach_port_t object,
 	munmap ((caddr_t) (data + (vm_page_size * i)), 
 		vm_page_size);
 
-      pm_entries[i] &= ~(PM_PAGINGOUT | PM_PAGEINWAIT);
+      pm_entries[i] &= ~(PM_PAGINGOUT | PM_PAGEINWAIT | PM_WRITEWAIT);
     }
 
-  wakeup = 0;
   for (ll = lock_list; ll; ll = ll->next)
     if (!--ll->lr->pending_writes && !ll->lr->locks_pending)
       wakeup = 1;
+
   if (wakeup)
     condition_broadcast (&p->wakeup);
 
diff --git a/libpager/lock-object.c b/libpager/lock-object.c
index 5182eff8..d108666e 100644
--- a/libpager/lock-object.c
+++ b/libpager/lock-object.c
@@ -1,5 +1,5 @@
 /* Synchronous wrapper for memory_object_lock_request
-   Copyright (C) 1993, 1994, 1996, 1997 Free Software Foundation
+   Copyright (C) 1993, 1994, 1996, 1997, 2000 Free Software Foundation
 
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
@@ -89,7 +89,7 @@ _pager_lock_object (struct pager *p,
 	  _pager_pagemap_resize (p, offset + size);
 	  if (p->pagemapsize > pm_offs)
 	    {
-	      char *pm_entries = &p->pagemap[pm_offs];
+	      short *pm_entries = &p->pagemap[pm_offs];
 	      vm_offset_t bound = size / vm_page_size;
 
 	      if (bound > p->pagemapsize)
diff --git a/libpager/mark-error.c b/libpager/mark-error.c
index 8b031479..5c4e029d 100644
--- a/libpager/mark-error.c
+++ b/libpager/mark-error.c
@@ -32,7 +32,7 @@ _pager_mark_next_request_error(struct pager *pager,
 			       error_t error)
 {
   int page_error;
-  char *p;
+  short *p;
 
   offset /= __vm_page_size;
   length /= __vm_page_size;
@@ -70,7 +70,7 @@ _pager_mark_object_error(struct pager *pager,
 			 error_t error)
 {
   int page_error = 0;
-  char *p;
+  short *p;
 
   offset /= __vm_page_size;
   length /= __vm_page_size;
diff --git a/libpager/object-terminate.c b/libpager/object-terminate.c
index 4315cbbb..dc53541c 100644
--- a/libpager/object-terminate.c
+++ b/libpager/object-terminate.c
@@ -1,5 +1,5 @@
 /* Implementation of memory_object_terminate for pager library
-   Copyright (C) 1994, 1995, 1996, 1999 Free Software Foundation
+   Copyright (C) 1994, 1995, 1996, 1999, 2000 Free Software Foundation
 
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
@@ -124,7 +124,7 @@ _pager_free_structure (struct pager *p)
   /* Free the pagemap */
   if (p->pagemapsize)
     {
-      munmap (p->pagemap, p->pagemapsize);
+      munmap (p->pagemap, p->pagemapsize * sizeof (* p->pagemap));
       p->pagemapsize = 0;
       p->pagemap = 0;
     }
diff --git a/libpager/offer-page.c b/libpager/offer-page.c
index 0d62da6a..aed22197 100644
--- a/libpager/offer-page.c
+++ b/libpager/offer-page.c
@@ -1,5 +1,5 @@
 /* Wrapper for unsolicited memory_object_data_supply
-   Copyright (C) 1996, 1997 Free Software Foundation, Inc.
+   Copyright (C) 1996, 1997, 2000 Free Software Foundation, Inc.
    Written by Michael I. Bushnell, p/BSG.
 
    This file is part of the GNU Hurd.
@@ -32,7 +32,7 @@ pager_offer_page (struct pager *p,
 
   if (_pager_pagemap_resize (p, offset + vm_page_size))
     {
-      char *pm_entry = &p->pagemap[offset / vm_page_size];
+      short *pm_entry = &p->pagemap[offset / vm_page_size];
 
       while (*pm_entry & PM_INCORE)
 	{
diff --git a/libpager/pagemap.c b/libpager/pagemap.c
index c6d924c7..b8b3362c 100644
--- a/libpager/pagemap.c
+++ b/libpager/pagemap.c
@@ -1,5 +1,5 @@
 /* Pagemap manipulation for pager library
-   Copyright (C) 1994, 1997, 1999 Free Software Foundation
+   Copyright (C) 1994, 1997, 1999, 2000 Free Software Foundation
 
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
@@ -31,12 +31,13 @@ _pager_pagemap_resize (struct pager *p, vm_address_t off)
       void *newaddr;
       int newsize = round_page (off);
 
-      newaddr = mmap (0, newsize, PROT_READ|PROT_WRITE, MAP_ANON, 0, 0);
+      newaddr = mmap (0, newsize * sizeof (*p->pagemap), 
+		      PROT_READ|PROT_WRITE, MAP_ANON, 0, 0);
       err = (newaddr == (void *) -1) ? errno : 0;
       if (! err)
 	{
-	  bcopy (p->pagemap, newaddr, p->pagemapsize);
-	  munmap (p->pagemap, p->pagemapsize);
+	  bcopy (p->pagemap, newaddr, p->pagemapsize * sizeof (*p->pagemap));
+	  munmap (p->pagemap, p->pagemapsize * sizeof (*p->pagemap));
 	  p->pagemap = newaddr;
 	  p->pagemapsize = newsize;
 	}
diff --git a/libpager/priv.h b/libpager/priv.h
index 0232e3e8..80afff1b 100644
--- a/libpager/priv.h
+++ b/libpager/priv.h
@@ -1,5 +1,5 @@
 /* Private data for pager library.
-   Copyright (C) 1994,95,96,97,99 Free Software Foundation, Inc.
+   Copyright (C) 1994,95,96,97,99, 2000 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
@@ -65,8 +65,8 @@ struct pager
   struct pending_init *init_head, *init_tail;
 #endif
 
-  char *pagemap;
-  int pagemapsize;
+  short *pagemap;
+  int pagemapsize;		/* number of elements in PAGEMAP */
 };
 
 struct lock_request
@@ -108,11 +108,12 @@ extern int _pager_page_errors[];
 
 /* Pagemap format */
 /* These are binary state bits */
-/* #define PM_INIT       0x80	data has been written */
-#define PM_INCORE     0x80	/* kernel might have a copy */
-#define PM_PAGINGOUT  0x40	/* being written to disk */
-#define PM_PAGEINWAIT 0x20	/* provide data back when write done */
-#define PM_INVALID    0x10	/* data on disk is irrevocably wrong */
+#define PM_WRITEWAIT  0x0200	/* queue wakeup once write is done */
+#define PM_INIT       0x0100    /* data has been written */
+#define PM_INCORE     0x0080	/* kernel might have a copy */
+#define PM_PAGINGOUT  0x0040	/* being written to disk */
+#define PM_PAGEINWAIT 0x0020	/* provide data back when write done */
+#define PM_INVALID    0x0010	/* data on disk is irrevocably wrong */
 
 /* These take values of enum page_errors */