diff -urN 2.4.11/fs/buffer.c lowlat/fs/buffer.c
--- 2.4.11/fs/buffer.c	Wed Oct 10 02:16:08 2001
+++ lowlat/fs/buffer.c	Thu Oct 11 09:15:31 2001
@@ -231,6 +231,7 @@
 static void write_unlocked_buffers(kdev_t dev)
 {
 	do {
+		conditional_schedule();
 		spin_lock(&lru_list_lock);
 	} while (write_some_buffers(dev));
 	run_task_queue(&tq_disk);
@@ -280,6 +281,7 @@
 static int wait_for_locked_buffers(kdev_t dev, int index, int refile)
 {
 	do {
+		conditional_schedule();
 		spin_lock(&lru_list_lock);
 	} while (wait_for_buffers(dev, index, refile));
 	return 0;
diff -urN 2.4.11/fs/proc/array.c lowlat/fs/proc/array.c
--- 2.4.11/fs/proc/array.c	Sun Sep 23 21:11:40 2001
+++ lowlat/fs/proc/array.c	Thu Oct 11 09:15:31 2001
@@ -414,6 +414,8 @@
 		pte_t page = *pte;
 		struct page *ptpage;
 
+		conditional_schedule();
+
 		address += PAGE_SIZE;
 		pte++;
 		if (pte_none(page))
diff -urN 2.4.11/fs/proc/generic.c lowlat/fs/proc/generic.c
--- 2.4.11/fs/proc/generic.c	Sun Sep 23 21:11:40 2001
+++ lowlat/fs/proc/generic.c	Thu Oct 11 09:15:31 2001
@@ -98,7 +98,9 @@
 				retval = n;
 			break;
 		}
-		
+
+		conditional_schedule();
+
 		/* This is a hack to allow mangling of file pos independent
  		 * of actual bytes read.  Simply place the data at page,
  		 * return the bytes, and set `start' to the desired offset
diff -urN 2.4.11/include/linux/condsched.h lowlat/include/linux/condsched.h
--- 2.4.11/include/linux/condsched.h	Thu Jan  1 01:00:00 1970
+++ lowlat/include/linux/condsched.h	Thu Oct 11 09:15:31 2001
@@ -0,0 +1,14 @@
+#ifndef _LINUX_CONDSCHED_H
+#define _LINUX_CONDSCHED_H
+
+#ifndef __ASSEMBLY__
+#define conditional_schedule() \
+do { \
+	if (unlikely(current->need_resched)) { \
+		__set_current_state(TASK_RUNNING); \
+		schedule(); \
+	} \
+} while(0)
+#endif
+
+#endif
diff -urN 2.4.11/include/linux/sched.h lowlat/include/linux/sched.h
--- 2.4.11/include/linux/sched.h	Sun Sep 23 21:11:42 2001
+++ lowlat/include/linux/sched.h	Thu Oct 11 09:15:31 2001
@@ -13,6 +13,7 @@
 #include <linux/times.h>
 #include <linux/timex.h>
 #include <linux/rbtree.h>
+#include <linux/condsched.h>
 
 #include <asm/system.h>
 #include <asm/semaphore.h>
diff -urN 2.4.11/mm/filemap.c lowlat/mm/filemap.c
--- 2.4.11/mm/filemap.c	Wed Oct 10 02:16:27 2001
+++ lowlat/mm/filemap.c	Thu Oct 11 09:16:27 2001
@@ -1264,6 +1264,9 @@
 		offset &= ~PAGE_CACHE_MASK;
 
 		page_cache_release(page);
+
+		conditional_schedule();
+
 		if (ret == nr && desc->count)
 			continue;
 		break;
@@ -2750,6 +2753,8 @@
 		SetPageReferenced(page);
 		UnlockPage(page);
 		page_cache_release(page);
+
+		conditional_schedule();
 
 		if (status < 0)
 			break;