From 15780e09157be4f1764e8a7c0bdeca7b4c63337b Mon Sep 17 00:00:00 2001
From: Zac Wen <zacw@meta.com>
Date: Wed, 1 May 2024 16:24:57 -0700
Subject: [PATCH] Record number of regions evicted in SsdCacheStats (#9686)

Summary: Pull Request resolved: https://github.com/facebookincubator/velox/pull/9686

Reviewed By: xiaoxmeng

Differential Revision: D56837945

Pulled By: zacw7

fbshipit-source-id: 7ad13d46e34b9b9ae70f90b4243f155c75c7aa80
---
 velox/common/caching/SsdFile.cpp | 2 ++
 velox/common/caching/SsdFile.h   | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/velox/common/caching/SsdFile.cpp b/velox/common/caching/SsdFile.cpp
index b4b7c37fa431..e977f610ebe3 100644
--- a/velox/common/caching/SsdFile.cpp
+++ b/velox/common/caching/SsdFile.cpp
@@ -347,6 +347,7 @@ bool SsdFile::growOrEvictLocked() {
 
   logEviction(candidates);
   clearRegionEntriesLocked(candidates);
+  stats_.regionsEvicted += candidates.size();
   writableRegions_ = std::move(candidates);
   suspended_ = false;
   return true;
@@ -532,6 +533,7 @@ void SsdFile::updateStats(SsdCacheStats& stats) const {
   }
   stats.entriesAgedOut += stats_.entriesAgedOut;
   stats.regionsAgedOut += stats_.regionsAgedOut;
+  stats.regionsEvicted += stats_.regionsEvicted;
   for (auto pins : regionPins_) {
     stats.numPins += pins;
   }
diff --git a/velox/common/caching/SsdFile.h b/velox/common/caching/SsdFile.h
index 8502a9d649a7..9b027cf9cb60 100644
--- a/velox/common/caching/SsdFile.h
+++ b/velox/common/caching/SsdFile.h
@@ -138,6 +138,7 @@ struct SsdCacheStats {
     bytesCached = tsanAtomicValue(other.bytesCached);
     entriesAgedOut = tsanAtomicValue(other.entriesAgedOut);
     regionsAgedOut = tsanAtomicValue(other.regionsAgedOut);
+    regionsEvicted = tsanAtomicValue(other.regionsEvicted);
     numPins = tsanAtomicValue(other.numPins);
 
     openFileErrors = tsanAtomicValue(other.openFileErrors);
@@ -162,6 +163,7 @@ struct SsdCacheStats {
   tsan_atomic<uint64_t> bytesCached{0};
   tsan_atomic<uint64_t> entriesAgedOut{0};
   tsan_atomic<uint64_t> regionsAgedOut{0};
+  tsan_atomic<uint64_t> regionsEvicted{0};
   tsan_atomic<int32_t> numPins{0};
 
   tsan_atomic<uint32_t> openFileErrors{0};