[master] f2882d3 Add ObjKill() for sniping an objcore, for instance for LRU-kills.

[Poul-Henning Kamp]

commit f2882d3c402522cef330cd84217f5cab44748768
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Wed Feb 3 09:02:40 2016 +0000

    Add ObjKill() for sniping an objcore, for instance for LRU-kills.

diff --git a/bin/varnishd/cache/cache.h b/bin/varnishd/cache/cache.h
index 7dfb482..e965cc3 100644
--- a/bin/varnishd/cache/cache.h
+++ b/bin/varnishd/cache/cache.h
@@ -855,12 +855,13 @@ ssize_t ObjWaitExtend(struct worker *, struct objcore *, ssize_t l);
 void ObjSetState(const struct objcore *, enum boc_state_e next);
 void ObjWaitState(const struct objcore *, enum boc_state_e want);
 void ObjTrimStore(struct worker *, struct objcore *);
-void ObjTouch(struct worker *wrk, struct objcore *oc, double now);
+void ObjTouch(struct worker *, struct objcore *, double now);
+int ObjKill(const struct worker *, struct objcore *);
 unsigned ObjGetXID(struct worker *, struct objcore *);
-uint64_t ObjGetLen(struct worker *, struct objcore *oc);
+uint64_t ObjGetLen(struct worker *, struct objcore *);
 void ObjUpdateMeta(struct worker *, struct objcore *);
 void ObjFreeObj(struct worker *, struct objcore *);
-void ObjSlim(struct worker *, struct objcore *oc);
+void ObjSlim(struct worker *, struct objcore *);
 struct lru *ObjGetLRU(const struct objcore *);
 int ObjHasAttr(struct worker *, struct objcore *, enum obj_attr);
 void *ObjGetAttr(struct worker *, struct objcore *, enum obj_attr,
@@ -879,7 +880,7 @@ int ObjGetDouble(struct worker *, struct objcore *, enum obj_attr, double *);
 int ObjGetU32(struct worker *, struct objcore *, enum obj_attr, uint32_t *);
 int ObjGetU64(struct worker *, struct objcore *, enum obj_attr, uint64_t *);
 
-int ObjCheckFlag(struct worker *, struct objcore *oc, enum obj_flags of);
+int ObjCheckFlag(struct worker *, struct objcore *, enum obj_flags of);
 void ObjSetFlag(struct worker *, struct objcore *, enum obj_flags of, int val);
 
 /* cache_panic.c */
diff --git a/bin/varnishd/cache/cache_expire.c b/bin/varnishd/cache/cache_expire.c
index 119f521..65cf46c 100644
--- a/bin/varnishd/cache/cache_expire.c
+++ b/bin/varnishd/cache/cache_expire.c
@@ -279,7 +279,6 @@ int
 EXP_NukeOne(struct worker *wrk, struct lru *lru)
 {
 	struct objcore *oc, *oc2;
-	struct objhead *oh;
 
 	CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC);
 	CHECK_OBJ_NOTNULL(lru, LRU_MAGIC);
@@ -292,30 +291,12 @@ EXP_NukeOne(struct worker *wrk, struct lru *lru)
 		    oc, oc->flags, oc->refcnt);
 
 		AZ(oc->exp_flags & OC_EF_OFFLRU);
-		AZ(oc->exp_flags & OC_EF_DYING);
-
-		/*
-		 * It wont release any space if we cannot release the last
-		 * reference, besides, if somebody else has a reference,
-		 * it's a bad idea to nuke this object anyway.
-		 */
-		if (oc->refcnt > 1)
-			continue;
-		oh = oc->objhead;
-		CHECK_OBJ_NOTNULL(oh, OBJHEAD_MAGIC);
-		if (Lck_Trylock(&oh->mtx))
-			continue;
-		if (oc->refcnt == 1) {
-			oc->exp_flags |= OC_EF_DYING | OC_EF_OFFLRU;
-			oc->refcnt++;
+
+		if (ObjKill(wrk, oc)) {
 			VSC_C_main->n_lru_nuked++; // XXX per lru ?
 			VTAILQ_REMOVE(&lru->lru_head, oc, lru_list);
-		} else {
-			oc = NULL;
-		}
-		Lck_Unlock(&oh->mtx);
-		if (oc != NULL)
 			break;
+		}
 	}
 	Lck_Unlock(&lru->mtx);
 
diff --git a/bin/varnishd/cache/cache_obj.c b/bin/varnishd/cache/cache_obj.c
index a1d2178..fb4c897 100644
--- a/bin/varnishd/cache/cache_obj.c
+++ b/bin/varnishd/cache/cache_obj.c
@@ -370,6 +370,35 @@ ObjTouch(struct worker *wrk, struct objcore *oc, double now)
 }
 
 /*====================================================================
+ * ObjKill()
+ *
+ * If objcore is idle, gain a ref and mark it dead.
+ */
+
+int
+ObjKill(const struct worker *wrk, struct objcore *oc)
+{
+	int retval = 0;
+
+	CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC);
+	CHECK_OBJ_NOTNULL(oc, OBJCORE_MAGIC);
+	CHECK_OBJ_NOTNULL(oc->objhead, OBJHEAD_MAGIC);
+
+	AZ(oc->exp_flags & OC_EF_DYING);
+
+	if (oc->refcnt == 1 && !Lck_Trylock(&oc->objhead->mtx)) {
+		if (oc->refcnt == 1) {
+			oc->exp_flags |= OC_EF_DYING;
+			oc->exp_flags |= OC_EF_OFFLRU;	/* XXX */
+			oc->refcnt++;
+			retval = 1;
+		}
+		Lck_Unlock(&oc->objhead->mtx);
+	}
+	return (retval);
+}
+
+/*====================================================================
  * Utility functions which work on top of the previous ones
  */