newvcache-dont-spin-20060128

make things so newvcache won't spin

diff --git a/src/afs/afs_vcache.c b/src/afs/afs_vcache.c
index a9c34bc..7a81bb3 100644 (file)
--- a/src/afs/afs_vcache.c
+++ b/src/afs/afs_vcache.c
@@ -787,6 +787,7 @@ restart:
 #else /* AFS_OSF_ENV */
     /* pull out a free cache entry */
     if (!freeVCList) {
+        int loop = 0;
        i = 0;
        for (tq = VLRU.prev; (anumber > 0) && (tq != &VLRU); tq = uq) {
            tvc = QTOV(tq);
@@ -814,6 +815,7 @@ restart:
                /* VREFCOUNT_GT only sees usecounts, not iocounts */
                /* so this may fail to actually recycle the vnode now */
                /* must call vnode_get to avoid races. */
+                fv_slept = 0;
                if (vnode_get(tvp) == 0) {
                    fv_slept=1;
                    /* must release lock, since vnode_put will immediately
@@ -828,9 +830,13 @@ restart:
                /* we can't use the vnode_recycle return value to figure
                 * this out, since the iocount we have to hold makes it
                 * always "fail" */
-               if (AFSTOV(tvc) == tvp)
+               if (AFSTOV(tvc) == tvp) {
+                    if (anumber > 0 && fv_slept) {
+                       QRemove(&tvc->vlruq);
+                       QAdd(&VLRU, &tvc->vlruq);
+                    }
                    code = EBUSY;
-               else
+               } else
                    code = 0;
 #else
                 /*
@@ -853,6 +859,8 @@ restart:
                    anumber--;
                }
                if (fv_slept) {
+                    if (loop++ > 100)
+                       break;
                    uq = VLRU.prev;
                    i = 0;
                    continue;   /* start over - may have raced. */