Fix code cache allocation with large pages enabled

When large pages/huge pages are enabled and page size >= 1GB, code cache size is rounded up to the page size. When codecachetotal is lesser than the page size, this can make the size of code cache segment bigger than the total code cache size. In this case, page size should be recalculated to a smaller value. Also a warning message should be printed in the verbose output. Closes: ##18274 Signed-off-by: SajinaKandy <[email protected]>
eclipse-openj9 · Oct 31, 2023 · 040228e · 040228e
1 parent a80c01f
commit 040228e
Showing 1 changed file with 15 additions and 0 deletions.
diff --git a/runtime/compiler/runtime/J9CodeCacheManager.cpp b/runtime/compiler/runtime/J9CodeCacheManager.cpp
@@ -286,6 +286,8 @@ J9::CodeCacheManager::allocateCodeCacheSegment(size_t segmentSize,
 
    TR::CodeCacheConfig &config = self()->codeCacheConfig();
 
+   UDATA ccTotalSizeB = config.codeCacheTotalKB() << 10;
+
    size_t largeCodePageSize = config.largeCodePageSize();
 #if defined(TR_TARGET_POWER) && defined(TR_HOST_POWER)
    /* Use largeCodePageSize on PPC only if its 16M.
@@ -298,6 +300,19 @@ J9::CodeCacheManager::allocateCodeCacheSegment(size_t segmentSize,
       {
       vmemParams.pageSize = largeCodePageSize;
       vmemParams.pageFlags = config.largeCodePageFlags();
+
+      // Recalculate the page size if using large pages
+      UDATA *pageSizes = j9vmem_supported_page_sizes();
+      if(vmemParams.pageSize > ccTotalSizeB)
+         {
+         for (UDATA pageIndex = 0; 0 != pageSizes[pageIndex]; ++pageIndex)
+            {
+            if(pageSizes[pageIndex] <= ccTotalSizeB)
+               vmemParams.pageSize = pageSizes[pageIndex];
+            }
+         if (config.verboseCodeCache() || config.verbosePerformance())
+            TR_VerboseLog::writeLineLocked(TR_Vlog_CODECACHE,"Warning: Using page size %zu instead of large page size %zu", (size_t)vmemParams.pageSize, largeCodePageSize);
+         }
       }
 
    UDATA mode = J9PORT_VMEM_MEMORY_MODE_READ |