--- linux-2.4.0-test3/include/linux/sched.h	Tue Jul 11 22:21:17 2000
+++ linux-akpm/include/linux/sched.h	Wed Jul 12 20:36:37 2000
@@ -146,6 +146,8 @@
 extern signed long FASTCALL(schedule_timeout(signed long timeout));
 asmlinkage void schedule(void);
 
+#define conditional_schedule() do { if (current->need_resched) schedule(); } while (0)
+
 /*
  * The default fd array needs to be at least BITS_PER_LONG,
  * as this is the granularity returned by copy_fdset().
--- linux-2.4.0-test3/include/linux/mm.h	Tue Jul 11 22:21:17 2000
+++ linux-akpm/include/linux/mm.h	Wed Jul 12 20:36:37 2000
@@ -178,6 +178,11 @@
 				/* bits 21-30 unused */
 #define PG_reserved		31
 
+/* Actions for zap_page_range() */
+#define ZPR_FLUSH_CACHE		1	/* Do flush_cache_range() prior to releasing pages */
+#define ZPR_FLUSH_TLB		2	/* Do flush_tlb_range() after releasing pages */
+#define ZPR_DEFER_FREE_PAGE	4	/* Defer passing of pages to free_page until after flush_tlb_range() */
+#define ZPR_COND_RESCHED	8	/* Do a conditional_schedule() occasionally */
 
 /* Make it prettier to test the above... */
 #define Page_Uptodate(page)	test_bit(PG_uptodate, &(page)->flags)
@@ -399,7 +404,7 @@
 
 extern int map_zero_setup(struct vm_area_struct *);
 
-extern void zap_page_range(struct mm_struct *mm, unsigned long address, unsigned long size);
+extern void zap_page_range(struct mm_struct *mm, unsigned long address, unsigned long size, int actions);
 extern int copy_page_range(struct mm_struct *dst, struct mm_struct *src, struct vm_area_struct *vma);
 extern int remap_page_range(unsigned long from, unsigned long to, unsigned long size, pgprot_t prot);
 extern int zeromap_page_range(unsigned long from, unsigned long size, pgprot_t prot);
--- linux-2.4.0-test3/mm/filemap.c	Tue Jul 11 22:21:17 2000
+++ linux-akpm/mm/filemap.c	Wed Jul 12 20:50:40 2000
@@ -160,6 +160,7 @@
 	start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 
 repeat:
+	conditional_schedule();		/* sys_unlink() */
 	head = &mapping->pages;
 	spin_lock(&pagecache_lock);
 	curr = head->next;
@@ -450,6 +451,7 @@
 
 		page_cache_get(page);
 		spin_unlock(&pagecache_lock);
+		conditional_schedule();		/* sys_msync() */
 		lock_page(page);
 
 		/* The buffers could have been free'd while we waited for the page lock */
@@ -1081,6 +1083,8 @@
 		 * "pos" here (the actor routine has to update the user buffer
 		 * pointers and the remaining count).
 		 */
+		conditional_schedule();		/* sys_read() */
+
 		nr = actor(desc, page, offset, nr);
 		offset += nr;
 		index += offset >> PAGE_CACHE_SHIFT;
@@ -1533,6 +1537,7 @@
 	 * vma/file is guaranteed to exist in the unmap/sync cases because
 	 * mmap_sem is held.
 	 */
+	conditional_schedule();		/* sys_msync() */
 	return page->mapping->a_ops->writepage(file, page);
 }
 
@@ -2022,9 +2027,8 @@
 	if (vma->vm_flags & VM_LOCKED)
 		return -EINVAL;
 
-	flush_cache_range(vma->vm_mm, start, end);
-	zap_page_range(vma->vm_mm, start, end - start);
-	flush_tlb_range(vma->vm_mm, start, end);
+	zap_page_range(vma->vm_mm, start, end - start,
+			ZPR_FLUSH_CACHE|ZPR_FLUSH_TLB|ZPR_COND_RESCHED);	/* sys_madvise(MADV_DONTNEED) */
 	return 0;
 }
 
@@ -2487,6 +2491,8 @@
 	while (count) {
 		unsigned long bytes, index, offset;
 		char *kaddr;
+
+		conditional_schedule();		/* sys_write() */
 
 		/*
 		 * Try to find the page in the cache. If it isn't there,
--- linux-2.4.0-test3/fs/buffer.c	Tue Jul 11 22:21:16 2000
+++ linux-akpm/fs/buffer.c	Sun Jul  9 23:51:04 2000
@@ -2123,6 +2123,7 @@
 				__wait_on_buffer(p);
 		} else if (buffer_dirty(p))
 			ll_rw_block(WRITE, 1, &p);
+		conditional_schedule();		/* sys_msync() */
 	} while (tmp != bh);
 }
 
--- linux-2.4.0-test3/mm/memory.c	Tue May 16 05:00:33 2000
+++ linux-akpm/mm/memory.c	Tue Jul 11 20:57:32 2000
@@ -347,7 +347,7 @@
 /*
  * remove user pages in a given range.
  */
-void zap_page_range(struct mm_struct *mm, unsigned long address, unsigned long size)
+static void do_zap_page_range(struct mm_struct *mm, unsigned long address, unsigned long size)
 {
 	pgd_t * dir;
 	unsigned long end = address + size;
@@ -381,6 +381,25 @@
 	}
 }
 
+#define MAX_ZAP_BYTES 512*PAGE_SIZE	/* 1 millisec @ 250 MHz */
+
+void zap_page_range(struct mm_struct *mm, unsigned long address, unsigned long size, int actions)
+{
+	while (size) {
+		unsigned long chunk = size;
+		if (actions & ZPR_COND_RESCHED && chunk > MAX_ZAP_BYTES)
+			chunk = MAX_ZAP_BYTES;
+		if (actions & ZPR_FLUSH_CACHE)
+			flush_cache_range(mm, address, address + chunk);
+		do_zap_page_range(mm, address, chunk);
+		if (actions & ZPR_FLUSH_TLB)
+			flush_tlb_range(mm, address, address + chunk);
+		if (actions & ZPR_COND_RESCHED)
+			conditional_schedule();
+		address += chunk;
+		size -= chunk;
+	}
+}
 
 /*
  * Do a quick page-table lookup for a single page. 
@@ -961,9 +980,7 @@
 
 		/* mapping wholly truncated? */
 		if (mpnt->vm_pgoff >= pgoff) {
-			flush_cache_range(mm, start, end);
-			zap_page_range(mm, start, len);
-			flush_tlb_range(mm, start, end);
+			zap_page_range(mm, start, len, ZPR_FLUSH_CACHE|ZPR_FLUSH_TLB);
 			continue;
 		}
 
@@ -981,7 +998,7 @@
 			start = (start + ~PAGE_MASK) & PAGE_MASK;
 		}
 		flush_cache_range(mm, start, end);
-		zap_page_range(mm, start, len);
+		zap_page_range(mm, start, len, 0);
 		flush_tlb_range(mm, start, end);
 	} while ((mpnt = mpnt->vm_next_share) != NULL);
 out_unlock:
--- linux-2.4.0-test3/mm/mmap.c	Tue Jul 11 22:21:17 2000
+++ linux-akpm/mm/mmap.c	Wed Jul 12 20:48:58 2000
@@ -340,9 +340,8 @@
 	vma->vm_file = NULL;
 	fput(file);
 	/* Undo any partial mapping done by a device driver. */
-	flush_cache_range(mm, vma->vm_start, vma->vm_end);
-	zap_page_range(mm, vma->vm_start, vma->vm_end - vma->vm_start);
-	flush_tlb_range(mm, vma->vm_start, vma->vm_end);
+	zap_page_range(mm, vma->vm_start, vma->vm_end - vma->vm_start,
+			ZPR_FLUSH_CACHE|ZPR_FLUSH_TLB);
 free_vma:
 	kmem_cache_free(vm_area_cachep, vma);
 	return error;
@@ -711,10 +710,8 @@
 		}
 		remove_shared_vm_struct(mpnt);
 		mm->map_count--;
-
-		flush_cache_range(mm, st, end);
-		zap_page_range(mm, st, size);
-		flush_tlb_range(mm, st, end);
+		zap_page_range(mm, st, size,
+			ZPR_FLUSH_CACHE|ZPR_FLUSH_TLB|ZPR_COND_RESCHED);	/* sys_munmap() */
 
 		/*
 		 * Fix the mapping, and free the old area if it wasn't reused.
@@ -864,7 +861,7 @@
 		}
 		mm->map_count--;
 		remove_shared_vm_struct(mpnt);
-		zap_page_range(mm, start, size);
+		zap_page_range(mm, start, size, ZPR_COND_RESCHED);	/* sys_exit() */
 		if (mpnt->vm_file)
 			fput(mpnt->vm_file);
 		kmem_cache_free(vm_area_cachep, mpnt);
--- linux-2.4.0-test3/mm/mremap.c	Sat Jun 24 15:39:47 2000
+++ linux-akpm/mm/mremap.c	Tue Jul 11 21:02:33 2000
@@ -118,8 +118,7 @@
 	flush_cache_range(mm, new_addr, new_addr + len);
 	while ((offset += PAGE_SIZE) < len)
 		move_one_page(mm, new_addr + offset, old_addr + offset);
-	zap_page_range(mm, new_addr, len);
-	flush_tlb_range(mm, new_addr, new_addr + len);
+	zap_page_range(mm, new_addr, len, ZPR_FLUSH_TLB);
 	return -1;
 }
 
--- linux-2.4.0-test3/drivers/char/mem.c	Sat Jun 24 15:39:43 2000
+++ linux-akpm/drivers/char/mem.c	Mon Jul 10 21:58:33 2000
@@ -373,8 +373,7 @@
 		if (count > size)
 			count = size;
 
-		flush_cache_range(mm, addr, addr + count);
-		zap_page_range(mm, addr, count);
+		zap_page_range(mm, addr, count, ZPR_FLUSH_CACHE);
         	zeromap_page_range(addr, count, PAGE_COPY);
         	flush_tlb_range(mm, addr, addr + count);