Formerly pager.c.~30~

1 files changed, 7 insertions, 0 deletions

diff --git a/ufs/pager.c b/ufs/pager.c
index 4de29518..1916a79e 100644
--- a/ufs/pager.c
+++ b/ufs/pager.c
@@ -46,6 +46,13 @@ static struct mutex pagernplock = MUTEX_INITIALIZER;
 
 char typechars[] = "ICSDF";
 
+/* Limit the number of outstanding FILE_DATA paging requests.  
+   Otherwise the kernel can send all the data at once and overwhelm us. */
+#define DATA_MAX_THREADS 10
+static int ndatapagethreads;
+static struct mutex ndpthreads_lock = MUTEX_INITIALIZER;
+static struct condition ndpthreads_wait = CONDITION_INITIALIZER;
+
 /* Find the location on disk of page OFFSET in pager UPI.  Return the
    disk address (in disk block) in *ADDR.  If *NPLOCK is set on
    return, then release that mutex after I/O on the data has