fix infinite sleep in performEvictions when have lazyfree jobs (#11237)

This bug is introduced in #7653. (Redis 6.2.0)

When `server.maxmemory_eviction_tenacity` is 100, `eviction_time_limit_us` is
`ULONG_MAX`, and if we cannot find the best key to delete (e.g. maxmemory-policy
is `volatile-lru` and all keys with ttl have been evicted), in `cant_free` redis will sleep
forever if some items are being freed in the lazyfree thread.

(cherry picked from commit 464aa04188c42c82f411ac7d43fabf0f6038c98e)

1 files changed, 9 insertions, 3 deletions

diff --git a/src/evict.c b/src/evict.c
index d3cdaaa80..ab46d1af6 100644
--- a/src/evict.c
+++ b/src/evict.c
@@ -549,7 +549,7 @@ int performEvictions(void) {
         {
             struct evictionPoolEntry *pool = EvictionPoolLRU;
 
-            while(bestkey == NULL) {
+            while (bestkey == NULL) {
                 unsigned long total_keys = 0, keys;
 
                 /* We don't want to make local-db choices when expiring keys,
@@ -695,12 +695,18 @@ cant_free:
         /* At this point, we have run out of evictable items.  It's possible
          * that some items are being freed in the lazyfree thread.  Perform a
          * short wait here if such jobs exist, but don't wait long.  */
-        if (bioPendingJobsOfType(BIO_LAZY_FREE)) {
-            usleep(eviction_time_limit_us);
+        mstime_t lazyfree_latency;
+        latencyStartMonitor(lazyfree_latency);
+        while (bioPendingJobsOfType(BIO_LAZY_FREE) &&
+              elapsedUs(evictionTimer) < eviction_time_limit_us) {
             if (getMaxmemoryState(NULL,NULL,NULL,NULL) == C_OK) {
                 result = EVICT_OK;
+                break;
             }
+            usleep(eviction_time_limit_us < 1000 ? eviction_time_limit_us : 1000);
         }
+        latencyEndMonitor(lazyfree_latency);
+        latencyAddSampleIfNeeded("eviction-lazyfree",lazyfree_latency);
     }
 
     latencyEndMonitor(latency);