mem: Limit the accesses to a page before forcing a precharge

This patch adds a basic starvation-prevention mechanism where a DRAM
page is forced to close after a certain number of accesses. The limit
is combined with the open and open-adaptive page policy and if reached
causes an auto-precharge.

1 files changed, 8 insertions, 1 deletions

diff --git a/src/mem/simple_dram.hh b/src/mem/simple_dram.hh
index 8ecce94b7..7f58843aa 100644
--- a/src/mem/simple_dram.hh
+++ b/src/mem/simple_dram.hh
@@ -155,11 +155,12 @@ class SimpleDRAM : public AbstractMemory
         Tick tRASDoneAt;
         Tick actAllowedAt;
 
+        uint32_t rowAccesses;
         uint32_t bytesAccessed;
 
         Bank() :
             openRow(INVALID_ROW), freeAt(0), tRASDoneAt(0), actAllowedAt(0),
-            bytesAccessed(0)
+            rowAccesses(0), bytesAccessed(0)
         { }
     };
 
@@ -508,6 +509,12 @@ class SimpleDRAM : public AbstractMemory
     Enums::PageManage pageMgmt;
 
     /**
+     * Max column accesses (read and write) per row, before forefully
+     * closing it.
+     */
+    const uint32_t maxAccessesPerRow;
+
+    /**
      * Pipeline latency of the controller frontend. The frontend
      * contribution is added to writes (that complete when they are in
      * the write buffer) and reads that are serviced the write buffer.