Module registry initial implementation

To address potential LPA shortages when multiple ZIS instances are
running on the same LPAR, a new feature--the module registry--has been
introduced.

The module registry is a set of data structures in common storage in
which eligible modules are traced. An eligible module is a module marked
with a special macro; the mark and the module names are then used to
uniquely identify the module. Once ZIS and its plug-in modules are
marked, they can be added to the registry and shared: if another ZIS
instance needs to load an identical module to the LPA, it will reuse
a previously registered (and loaded to the LPA) module instead. Sharing
identical modules should dramatically decrease the LPA footprint.

This feature must not be used when an application wants to remove its
modules from the LPA (e.g., ZIS does that in dev mode) because it will
affect any other applications using the same modules.

Fixes: #405

Signed-off-by: Irek Fakhrutdinov <[email protected]>

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## `3.1.0`
 - Bugfix: removed "ByteOutputStream" debug message, which was part of the `zwe` command output (#491)
 - Bugfix: HEAPPOOLS and HEAPPOOLS64 no longer need to be set to OFF for configmgr (#497)
+- Enhancement: module registry (#405)
 
 ## `3.0.0`
 - Feature: added javascript `zos.getStatvfs(path)` function to obtain file system information (#482).

c/crossmemory.c

@@ -42,6 +42,7 @@
 #include "stcbase.h"
 #include "utils.h"
 #include "zvt.h"
+#include "modreg.h"
 
 #define CMS_STATIC_ASSERT($expr) typedef char p[($expr) ? 1 : -1]
 
@@ -367,6 +368,8 @@ void cmsInitializeLogging() {
   logConfigureComponent(NULL, LOG_COMP_STCBASE, "STCBASE", LOG_DEST_PRINTF_STDOUT, ZOWE_LOG_INFO);
   logConfigureComponent(NULL, LOG_COMP_ID_CMS, "CIDB", LOG_DEST_PRINTF_STDOUT, ZOWE_LOG_INFO);
   logConfigureComponent(NULL, LOG_COMP_ID_CMSPC, "CIDB CM", LOG_DEST_PRINTF_STDOUT, ZOWE_LOG_INFO);
+  logConfigureComponent(NULL, LOG_COMP_LPA, "LPA", LOG_DEST_PRINTF_STDOUT, ZOWE_LOG_INFO);
+  logConfigureComponent(NULL, LOG_COMP_MODREG, "MODREG", LOG_DEST_PRINTF_STDOUT, ZOWE_LOG_INFO);
   printf("DATESTAMP              JOBNAME  ASCB    (ASID) TCB       MSGID     MSGTEXT\n");
 
 }
@@ -2442,6 +2445,8 @@ CrossMemoryServer *makeCrossMemoryServer2(
     logSetLevel(NULL, LOG_COMP_ID_CMS, ZOWE_LOG_DEBUG);
     logSetLevel(NULL, LOG_COMP_ID_CMSPC, ZOWE_LOG_DEBUG);
     logSetLevel(NULL, LOG_COMP_STCBASE, ZOWE_LOG_DEBUG);
+    logSetLevel(NULL, LOG_COMP_LPA, ZOWE_LOG_DEBUG);
+    logSetLevel(NULL, LOG_COMP_MODREG, ZOWE_LOG_DEBUG);
   }
 
   EightCharString cmsModule = {0};
@@ -2483,6 +2488,10 @@ CrossMemoryServer *makeCrossMemoryServer2(
     server->flags |= CROSS_MEMORY_SERVER_FLAG_RESET_LOOKUP;
   }
 
+  if (flags & CMS_SERVER_FLAG_USE_MODREG) {
+    server->flags |= CROSS_MEMORY_SERVER_FLAG_USE_MODREG;
+  }
+
   int allocResourcesRC = allocServerResources(server);
   if (allocResourcesRC != RC_CMS_OK) {
     safeFree31((char *)server, sizeof(CrossMemoryServer));
@@ -3388,17 +3397,41 @@ static int allocateGlobalResources(CrossMemoryServer *server) {
   globalArea->serverFlags |= server->flags;
   globalArea->serverASID = getMyPASID();
 
-  /* Load the module to LPA if needed, otherwise re-use the existing module. */
+  const char *statusText = "n/a";
+  /* Register the module or load it to LPA if needed, otherwise re-use the
+   * existing module. */
   if (moduleAddressLPA == NULL) {
-
-    int lpaAddRSN = 0;
-    int lpaAddRC = lpaAdd(&server->lpaCodeInfo, &server->ddname, &server->dsname,
-                          &lpaAddRSN);
-    if (lpaAddRC != 0) {
-      zowelog(NULL, LOG_COMP_ID_CMS, ZOWE_LOG_SEVERE, CMS_LOG_LPA_LOAD_FAILURE_MSG, lpaAddRC, lpaAddRSN);
-      return RC_CMS_LPA_ADD_FAILED;
+    /* Load to the LPA manually only if the "clean LPA" (dev mode) is enabled
+     * or the "use module registry" option is disabled. */
+    if (server->flags & CROSS_MEMORY_SERVER_FLAG_CLEAN_LPA ||
+        !(server->flags & CROSS_MEMORY_SERVER_FLAG_USE_MODREG)) {
+      int lpaAddRSN = 0;
+      int lpaAddRC = lpaAdd(&server->lpaCodeInfo, &server->ddname,
+                            &server->dsname, &lpaAddRSN);
+      if (lpaAddRC == 0) {
+        statusText = "own instance loaded to LPA";
+      } else {
+        zowelog(NULL, LOG_COMP_ID_CMS, ZOWE_LOG_SEVERE,
+                CMS_LOG_LPA_LOAD_FAILURE_MSG, lpaAddRC, lpaAddRSN);
+        return RC_CMS_LPA_ADD_FAILED;
+      }
+    } else {
+      uint64_t modregRSN;
+      int modregRC = modregRegister(server->ddname, server->dsname,
+                                    &server->lpaCodeInfo, &modregRSN);
+      if (modregRC == RC_MODREG_OK) {
+        statusText = "new instance added to registry";
+      } else if (modregRC == RC_MODREG_ALREADY_REGISTERED) {
+        statusText = "instance reused from registry";
+      } else {
+        zowelog(NULL, LOG_COMP_ID_CMS, ZOWE_LOG_SEVERE,
+                CMS_LOG_MODREG_ADD_FAILURE_MSG, modregRC, modregRSN);
+        return RC_CMS_MODREG_FAILED;
+      }
     }
     globalArea->lpaModuleInfo = server->lpaCodeInfo;
+    moduleAddressLPA =
+        server->lpaCodeInfo.outputInfo.stuff.successInfo.loadPointAddr;
 
     zowelog(NULL, LOG_COMP_ID_CMS, ZOWE_LOG_DEBUG, CMS_LOG_DEBUG_MSG_ID
             " module successfully loaded into LPA @ 0x%p, LPMEA:\n",
@@ -3408,6 +3441,7 @@ static int allocateGlobalResources(CrossMemoryServer *server) {
 
   } else {
 
+    statusText = "previously added/loaded instance reused";
     server->lpaCodeInfo = globalArea->lpaModuleInfo;
 
     zowelog(NULL, LOG_COMP_ID_CMS, ZOWE_LOG_DEBUG, CMS_LOG_DEBUG_MSG_ID
@@ -3417,9 +3451,11 @@ static int allocateGlobalResources(CrossMemoryServer *server) {
 
   }
 
+  zowelog(NULL, LOG_COMP_ID_CMS, ZOWE_LOG_INFO, CMS_LOG_MODULE_STATUS_MSG,
+          statusText, moduleAddressLPA);
+
   /* The required module is in LPA, update the corresponding fields. */
   globalArea->lpaModuleTimestamp = getServerBuildTimestamp();
-  moduleAddressLPA = server->lpaCodeInfo.outputInfo.stuff.successInfo.loadPointAddr;
   server->moduleAddressLPA = moduleAddressLPA;
 
   /* Prepare the service table */
@@ -4925,6 +4961,8 @@ static int testEnvironment(const CrossMemoryServer *srv) {
 
 int cmsStartMainLoop(CrossMemoryServer *srv) {
 
+  MODREG_MARK_MODULE();
+
   int envStatus = testEnvironment(srv);
   if (envStatus != 0) {
     return envStatus;