Optimize eviction of subsequent segments of the same object

src/fellow_cache.c

@@ -3134,6 +3134,7 @@ fellow_cache_lru_work(struct worker *wrk, struct fellow_cache_lru *lru)
 	oc = NULL;
 	fco = NULL;
 	AZ(pthread_mutex_lock(&lru->lru_mtx));
+	//lint -e{850} loop variable modified in body
 	VTAILQ_FOREACH_SAFE(fcs, &lru->lru_head, lru_list, fcss) {
 		// no use trying the same object again and again
 		if (fcs->fco == fco)
@@ -3146,10 +3147,22 @@ fellow_cache_lru_work(struct worker *wrk, struct fellow_cache_lru *lru)
 			continue;
 		}
 		if (fcs->state == FCS_INCORE) {
-			fellow_cache_lru_seg_evict_locked(fcs,
-			    &alloc, lru);
+			do {
+				fellow_cache_lru_seg_evict_locked(fcs,
+				    &alloc, lru);
+				AN(buddy_return_ptr_extent(rets, &alloc));
+
+				if (rets->size < lru->fc->membuddy->deficit &&
+				    fcss != NULL &&
+				    fcss->state == FCS_INCORE &&
+				    fcss->fco == fco) {
+					fcs = fcss;
+					fcss = VTAILQ_NEXT(fcs, lru_list);
+					continue;
+				}
+			} while (0);
+
 			AZ(pthread_mutex_unlock(&fco->mtx));
-			AN(buddy_return_ptr_extent(rets, &alloc));
 			fco = NULL;
 			if (rets->size < lru->fc->membuddy->deficit)
 				continue;