From a7c5533b381db87d6eb74c6cf8140471b776a773 Mon Sep 17 00:00:00 2001
From: Igor Chorazewicz <igor.chorazewicz@intel.com>
Date: Tue, 25 Apr 2023 13:35:24 -0700
Subject: [PATCH 1/2] Fix issue with token creation

---
 cachelib/allocator/CacheAllocator-inl.h | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/cachelib/allocator/CacheAllocator-inl.h b/cachelib/allocator/CacheAllocator-inl.h
index 954d533daa..53ef5aba22 100644
--- a/cachelib/allocator/CacheAllocator-inl.h
+++ b/cachelib/allocator/CacheAllocator-inl.h
@@ -1603,13 +1603,15 @@ CacheAllocator<CacheTrait>::findEviction(TierId tid, PoolId pid, ClassId cid) {
                 ? &toRecycle_->asChainedItem().getParentItem(compressor_)
                 : toRecycle_;
 
-        if (lastTier) {
-          // if it's last tier, the item will be evicted
-          // need to create put token before marking it exclusive
-          token = createPutToken(*candidate_);
-        }
+        // if it's last tier, the item will be evicted
+        // need to create put token before marking it exclusive
+        const bool evictToNvmCache = lastTier && shouldWriteToNvmCache(*candidate_);
+
+        auto token_ = evictToNvmCache
+                          ? nvmCache_->createPutToken(candidate_->getKey())
+                          : typename NvmCacheT::PutToken{};
 
-        if (lastTier && shouldWriteToNvmCache(*candidate_) && !token.isValid()) {
+        if (evictToNvmCache && !token_.isValid()) {
           stats_.evictFailConcurrentFill.inc();
         } else if ( (lastTier && candidate_->markForEviction()) ||
                     (!lastTier && candidate_->markMoving(true)) ) {
@@ -1619,6 +1621,7 @@ CacheAllocator<CacheTrait>::findEviction(TierId tid, PoolId pid, ClassId cid) {
           // since we won't be moving the item to the next tier
           toRecycle = toRecycle_;
           candidate = candidate_;
+          token = std::move(token_);
 
           // Check if parent changed for chained items - if yes, we cannot
           // remove the child from the mmContainer as we will not be evicting
@@ -1626,8 +1629,9 @@ CacheAllocator<CacheTrait>::findEviction(TierId tid, PoolId pid, ClassId cid) {
           // unmarkForEviction() returns 0 - so just go through normal path.
           if (!toRecycle_->isChainedItem() ||
               &toRecycle->asChainedItem().getParentItem(compressor_) ==
-                  candidate)
+                  candidate) {
             mmContainer.remove(itr);
+          }
           return;
         }
 
@@ -1643,8 +1647,9 @@ CacheAllocator<CacheTrait>::findEviction(TierId tid, PoolId pid, ClassId cid) {
       }
     });
 
-    if (!toRecycle)
+    if (!toRecycle) {
       continue;
+    }
 
     XDCHECK(toRecycle);
     XDCHECK(candidate);

From 7d844e72f9e72753118a80a5a398216f3e5cbde2 Mon Sep 17 00:00:00 2001
From: Igor Chorazewicz <igor.chorazewicz@intel.com>
Date: Wed, 26 Apr 2023 08:05:09 -0700
Subject: [PATCH 2/2] Do not increment evictFail* stats if
 evictFailConcurrentFill were incremented

---
 cachelib/allocator/CacheAllocator-inl.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/cachelib/allocator/CacheAllocator-inl.h b/cachelib/allocator/CacheAllocator-inl.h
index 53ef5aba22..48fbafb356 100644
--- a/cachelib/allocator/CacheAllocator-inl.h
+++ b/cachelib/allocator/CacheAllocator-inl.h
@@ -1633,12 +1633,12 @@ CacheAllocator<CacheTrait>::findEviction(TierId tid, PoolId pid, ClassId cid) {
             mmContainer.remove(itr);
           }
           return;
-        }
-
-        if (candidate_->hasChainedItem()) {
-          stats_.evictFailParentAC.inc();
         } else {
-          stats_.evictFailAC.inc();
+          if (candidate_->hasChainedItem()) {
+            stats_.evictFailParentAC.inc();
+          } else {
+            stats_.evictFailAC.inc();
+          }
         }
 
         ++itr;