Removal of race conditions. Inspired by Charles Hannum's

<mycroft@netbsd.org> reorganization of the vm_collapse logic, although not
used verbatim.  We no longer collapse objects from the pagedaemon as that
is not necessary anymore with the more aggressive collapses that gets done.
This also increases performance of loaded systems.  Much KNF too.

1 files changed, 50 insertions, 52 deletions

diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
index 7ace4838f1b..4774428adcb 100644
--- a/sys/vm/swap_pager.c
+++ b/sys/vm/swap_pager.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: swap_pager.c,v 1.9 1997/03/05 12:49:38 niklas Exp $	*/
+/*	$OpenBSD: swap_pager.c,v 1.10 1997/04/17 01:25:16 niklas Exp $	*/
 /*	$NetBSD: swap_pager.c,v 1.27 1996/03/16 23:15:20 christos Exp $	*/
 
 /*
@@ -272,7 +272,7 @@ swap_pager_alloc(handle, size, prot, foff)
 			 */
 			if (vm_object_lookup(pager) == NULL)
 				panic("swap_pager_alloc: bad object");
-			return(pager);
+			return (pager);
 		}
 	}
 	/*
@@ -282,7 +282,7 @@ swap_pager_alloc(handle, size, prot, foff)
 	waitok = handle ? M_WAITOK : M_NOWAIT;
 	pager = (vm_pager_t)malloc(sizeof *pager, M_VMPAGER, waitok);
 	if (pager == NULL)
-		return(NULL);
+		return (NULL);
 	swp = (sw_pager_t)malloc(sizeof *swp, M_VMPGDATA, waitok);
 	if (swp == NULL) {
 #ifdef DEBUG
@@ -290,7 +290,7 @@ swap_pager_alloc(handle, size, prot, foff)
 			printf("swpg_alloc: swpager malloc failed\n");
 #endif
 		free((caddr_t)pager, M_VMPAGER);
-		return(NULL);
+		return (NULL);
 	}
 	size = round_page(size);
 	for (swt = swtab; swt->st_osize; swt++)
@@ -303,9 +303,8 @@ swap_pager_alloc(handle, size, prot, foff)
 	swp->sw_osize = size;
 	swp->sw_bsize = swt->st_bsize;
 	swp->sw_nblocks = (btodb(size) + swp->sw_bsize - 1) / swp->sw_bsize;
-	swp->sw_blocks = (sw_blk_t)
-		malloc(swp->sw_nblocks*sizeof(*swp->sw_blocks),
-		       M_VMPGDATA, M_NOWAIT);
+	swp->sw_blocks = (sw_blk_t)malloc(swp->sw_nblocks *
+	    sizeof(*swp->sw_blocks), M_VMPGDATA, M_NOWAIT);
 	if (swp->sw_blocks == NULL) {
 		free((caddr_t)swp, M_VMPGDATA);
 		free((caddr_t)pager, M_VMPAGER);
@@ -315,10 +314,10 @@ swap_pager_alloc(handle, size, prot, foff)
 		swt->st_inuse--;
 		swt->st_usecnt--;
 #endif
-		return(FALSE);
+		return (FALSE);
 	}
 	bzero((caddr_t)swp->sw_blocks,
-	      swp->sw_nblocks * sizeof(*swp->sw_blocks));
+	    swp->sw_nblocks * sizeof(*swp->sw_blocks));
 	swp->sw_poip = swp->sw_cnt = 0;
 	if (handle) {
 		vm_object_t object;
@@ -349,7 +348,7 @@ swap_pager_alloc(handle, size, prot, foff)
 		printf("swpg_alloc: pg_data %p, %x of %x at %p\n",
 		    swp, swp->sw_nblocks, swp->sw_bsize, swp->sw_blocks);
 #endif
-	return(pager);
+	return (pager);
 }
 
 static void
@@ -451,7 +450,7 @@ swap_pager_getpage(pager, mlist, npages, sync)
 		m->flags &= ~PG_FAULTING;
 	}
 #endif
-	return(rv);
+	return (rv);
 }
 
 static int
@@ -475,8 +474,8 @@ swap_pager_putpage(pager, mlist, npages, sync)
 	flags = B_WRITE;
 	if (!sync)
 		flags |= B_ASYNC;
-	return(swap_pager_io((sw_pager_t)pager->pg_data,
-			     mlist, npages, flags));
+	return (swap_pager_io((sw_pager_t)pager->pg_data, mlist, npages,
+	    flags));
 }
 
 static boolean_t
@@ -500,7 +499,7 @@ swap_pager_haspage(pager, offset)
 			printf("swpg_haspage: %p bad offset %lx, ix %x\n",
 			    swp->sw_blocks, offset, ix);
 #endif
-		return(FALSE);
+		return (FALSE);
 	}
 	swb = &swp->sw_blocks[ix];
 	if (swb->swb_block)
@@ -513,8 +512,8 @@ swap_pager_haspage(pager, offset)
 		    "FT"[swb->swb_block && (swb->swb_mask & (1 << ix))]);
 #endif
 	if (swb->swb_block && (swb->swb_mask & (1 << ix)))
-		return(TRUE);
-	return(FALSE);
+		return (TRUE);
+	return (FALSE);
 }
 
 static void
@@ -603,16 +602,16 @@ swap_pager_io(swp, mlist, npages, flags)
 #ifdef DEBUG
 		if ((flags & B_READ) == 0 && (swpagerdebug & SDB_ANOM)) {
 			printf("swap_pager_io: no swap block on write\n");
-			return(VM_PAGER_BAD);
+			return (VM_PAGER_BAD);
 		}
 #endif
-		return(VM_PAGER_FAIL);
+		return (VM_PAGER_FAIL);
 	}
 	swb = &swp->sw_blocks[ix];
 	off = off % dbtob(swp->sw_bsize);
 	if ((flags & B_READ) &&
 	    (swb->swb_block == 0 || (swb->swb_mask & (1 << atop(off))) == 0))
-		return(VM_PAGER_FAIL);
+		return (VM_PAGER_FAIL);
 
 	/*
 	 * For reads (pageins) and synchronous writes, we clean up
@@ -645,7 +644,7 @@ swap_pager_io(swp, mlist, npages, flags)
 				printf("%s: no available io headers\n",
 				    "swap_pager_io");
 #endif
-			return(VM_PAGER_AGAIN);
+			return (VM_PAGER_AGAIN);
 		}
 	}
 
@@ -667,7 +666,7 @@ swap_pager_io(swp, mlist, npages, flags)
 			 * trying again (the pageout daemon's current response
 			 * to AGAIN) so we just return FAIL.
 			 */
-			return(VM_PAGER_FAIL);
+			return (VM_PAGER_FAIL);
 		}
 #ifdef DEBUG
 		if (swpagerdebug & (SDB_FULL|SDB_ALLOCBLK))
@@ -687,7 +686,7 @@ swap_pager_io(swp, mlist, npages, flags)
 			printf("%s: no KVA space to map pages\n",
 			    "swap_pager_io");
 #endif
-		return(VM_PAGER_AGAIN);
+		return (VM_PAGER_AGAIN);
 	}
 
 	/*
@@ -795,7 +794,7 @@ swap_pager_io(swp, mlist, npages, flags)
 		if (swpagerdebug & SDB_IO)
 			printf("swpg_io:  IO started: bp %p\n", bp);
 #endif
-		return(VM_PAGER_PEND);
+		return (VM_PAGER_PEND);
 	}
 	s = splbio();
 #ifdef DEBUG
@@ -836,7 +835,7 @@ swap_pager_io(swp, mlist, npages, flags)
 		printf("swpg_io: IO error\n");
 #endif
 	vm_pager_unmap_pages(kva, npages);
-	return(rv);
+	return (rv);
 }
 
 static void
@@ -926,8 +925,7 @@ swap_pager_clean(rw)
 		 * Done with the object, decrement the paging count
 		 * and unlock it.
 		 */
-		if (--object->paging_in_progress == 0)
-			wakeup(object);
+		vm_object_paging_end(object);
 		vm_object_unlock(object);
 
 		/*
@@ -1066,7 +1064,7 @@ swap_pager_remove(pager, from, to)
 
 	/*	Special case stupid ranges.	*/
 	if (to > 0 && from >= to)
-		return(0);
+		return (0);
 
 	swp = (sw_pager_t)pager->pg_data;
 
@@ -1079,14 +1077,14 @@ swap_pager_remove(pager, from, to)
 	 *	be created without any pages put into it?
 	 */
 	if (swp->sw_cnt == 0)
-		return(0);
+		return (0);
 
 	bsize = dbtob(swp->sw_bsize);
 	blk = from / bsize;
 
 	/*	Another fast one.. no blocks in range.	*/
 	if (blk >= swp->sw_nblocks)
-		return(0);
+		return (0);
 	bit = atop(from % bsize);
 
 	/*
@@ -1149,18 +1147,18 @@ swap_pager_remove(pager, from, to)
 	if (swp->sw_cnt < 0)
 		panic("swap_pager_remove: sw_cnt < 0");
 #endif
-	return(cnt);
+	return (cnt);
 }
 
 /*
- *	swap_pager_next:
+ * swap_pager_next:
  *
- *	This is called via the vm_pager_next path and
- *	will return the offset of the next page (addresswise)
- *	which this pager is backing.  If there are no more
- *	pages we will return the size of the pager's managed
- *	space (which by definition is larger than any page's
- *	offset).
+ * This is called via the vm_pager_next path and
+ * will return the offset of the next page (addresswise)
+ * which this pager is backing.  If there are no more
+ * pages we will return the size of the pager's managed
+ * space (which by definition is larger than any page's
+ * offset).
  */
 static vm_offset_t
 swap_pager_next(pager, offset)
@@ -1179,22 +1177,22 @@ swap_pager_next(pager, offset)
 	swp = (sw_pager_t)pager->pg_data;
 
 	/*
-	 *	If we back no pages, just return our size.  XXX Can
-	 *	this ever be the case?  At least all remove calls
-	 *	should be through vm_object_remove_from_pager which
-	 *	also deallocates the pager when it no longer backs any
-	 *	pages.  Left is the initial case: can a swap-pager
-	 *	be created without any pages put into it?
+	 * If we back no pages, just return our size.  XXX Can
+	 * this ever be the case?  At least all remove calls
+	 * should be through vm_object_remove_from_pager which
+	 * also deallocates the pager when it no longer backs any
+	 * pages.  Left is the initial case: can a swap-pager
+	 * be created without any pages put into it?
 	 */
 	if (swp->sw_cnt == 0)
-		return(swp->sw_osize);
+		return (swp->sw_osize);
 
 	bsize = dbtob(swp->sw_bsize);
 	blk = offset / bsize;
 
-	/*	Another fast one.. no blocks in range.	*/
+	/* Another fast one.. no blocks in range.	*/
 	if (blk >= swp->sw_nblocks)
-		return(swp->sw_osize);
+		return (swp->sw_osize);
 	bit = atop(offset % bsize);
 	to_blk = swp->sw_osize / bsize;
 	to_bit = atop(swp->sw_osize % bsize);
@@ -1219,7 +1217,7 @@ swap_pager_next(pager, offset)
 		 */
 		mask &= swb->swb_mask;
 		if (mask)
-			return(blk * bsize + (ffs (mask) - 1) * PAGE_SIZE);
+			return (blk * bsize + (ffs (mask) - 1) * PAGE_SIZE);
 
 		/*
 		 *	If we handled the end of range now, this
@@ -1233,7 +1231,7 @@ swap_pager_next(pager, offset)
 		swb++;
 		mask = ~0;
  	}
-	return swp->sw_osize;
+	return (swp->sw_osize);
 }
 
 /*
@@ -1246,7 +1244,7 @@ swap_pager_count(pager)
 	vm_pager_t	pager;
 {
 #ifndef notyet
-	return((sw_pager_t)pager->pg_data)->sw_cnt;
+	return ((sw_pager_t)pager->pg_data)->sw_cnt;
 #else
 	sw_pager_t swp;
 	sw_blk_t swb;
@@ -1254,10 +1252,10 @@ swap_pager_count(pager)
 
 	swp = (sw_pager_t)pager->pg_data;
 	if (swp->sw_blocks == NULL)
-		return 0;
+		return (0);
 	for (i = 0; i < swp->sw_nblocks; i++)
 		cnt += count_bits(swp->sw_blocks[i].swb_mask); 
-	return cnt;
+	return (cnt);
 #endif
 }
 
@@ -1276,5 +1274,5 @@ count_bits(x)
 		cnt += x & 1;
 		x >>= 1;
 	}
-	return(cnt);
+	return (cnt);
 }