Accurate dictEntry memory usage calculation

Signed-off-by: Harkrishn Patro <[email protected]>
hpatro · Jun 27, 2024 · 4d30109 · 4d30109
1 parent e714f2c
commit 4d30109
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Showing 5 changed files with 16 additions and 9 deletions.
diff --git a/src/debug.c b/src/debug.c
@@ -864,7 +864,7 @@ void debugCommand(client *c) {
         sds sizes = sdsempty();
         sizes = sdscatprintf(sizes, "bits:%d ", (sizeof(void *) == 8) ? 64 : 32);
         sizes = sdscatprintf(sizes, "robj:%d ", (int)sizeof(robj));
-        sizes = sdscatprintf(sizes, "dictentry:%d ", (int)dictEntryMemUsage());
+        sizes = sdscatprintf(sizes, "dictentry:%d ", (int)dictEntryMemUsage(NULL));
         sizes = sdscatprintf(sizes, "sdshdr5:%d ", (int)sizeof(struct sdshdr5));
         sizes = sdscatprintf(sizes, "sdshdr8:%d ", (int)sizeof(struct sdshdr8));
         sizes = sdscatprintf(sizes, "sdshdr16:%d ", (int)sizeof(struct sdshdr16));

diff --git a/src/dict.c b/src/dict.c
@@ -968,8 +968,15 @@ size_t dictMemUsage(const dict *d) {
     return dictSize(d) * sizeof(dictEntry) + dictBuckets(d) * sizeof(dictEntry *);
 }
 
-size_t dictEntryMemUsage(void) {
-    return sizeof(dictEntry);
+/* Returns the memory usage in bytes of dictEntry based on the type. if `de` is NULL, return the size of
+ * regular dict entry else return based on the type. */
+size_t dictEntryMemUsage(dictEntry *de) {
+    if (de == NULL || entryIsNormal(de)) return sizeof(dictEntry);
+    else if (entryIsKey(de)) return 0;
+    else if (entryIsNoValue(de)) return sizeof(dictEntryNoValue);
+    else if (entryIsEmbedded(de)) return zmalloc_size(decodeEmbeddedEntry(de));
+    else assert("Entry type not supported");
+    return 0;
 }
 
 /* A fingerprint is a 64 bit number that represents the state of the dictionary

diff --git a/src/dict.h b/src/dict.h
@@ -220,7 +220,7 @@ uint64_t dictGetUnsignedIntegerVal(const dictEntry *de);
 double dictGetDoubleVal(const dictEntry *de);
 double *dictGetDoubleValPtr(dictEntry *de);
 size_t dictMemUsage(const dict *d);
-size_t dictEntryMemUsage(void);
+size_t dictEntryMemUsage(dictEntry *de);
 dictIterator *dictGetIterator(dict *d);
 dictIterator *dictGetSafeIterator(dict *d);
 void dictInitIterator(dictIterator *iter, dict *d);

diff --git a/src/kvstore.c b/src/kvstore.c
@@ -340,7 +340,7 @@ size_t kvstoreMemUsage(kvstore *kvs) {
     size_t mem = sizeof(*kvs);
 
     unsigned long long keys_count = kvstoreSize(kvs);
-    mem += keys_count * dictEntryMemUsage() + kvstoreBuckets(kvs) * sizeof(dictEntry *) +
+    mem += keys_count * dictEntryMemUsage(NULL) + kvstoreBuckets(kvs) * sizeof(dictEntry *) +
            kvs->allocated_dicts * (sizeof(dict) + kvstoreDictMetadataSize(NULL));
 
     /* Values are dict* shared with kvs->dicts */

diff --git a/src/object.c b/src/object.c
@@ -1010,7 +1010,7 @@ size_t objectComputeSize(robj *key, robj *o, size_t sample_size, int dbid) {
             asize = sizeof(*o) + sizeof(dict) + (sizeof(struct dictEntry *) * dictBuckets(d));
             while ((de = dictNext(di)) != NULL && samples < sample_size) {
                 ele = dictGetKey(de);
-                elesize += dictEntryMemUsage() + sdsZmallocSize(ele);
+                elesize += dictEntryMemUsage(de) + sdsZmallocSize(ele);
                 samples++;
             }
             dictReleaseIterator(di);
@@ -1033,7 +1033,7 @@ size_t objectComputeSize(robj *key, robj *o, size_t sample_size, int dbid) {
                     (sizeof(struct dictEntry *) * dictBuckets(d)) + zmalloc_size(zsl->header);
             while (znode != NULL && samples < sample_size) {
                 elesize += sdsZmallocSize(znode->ele);
-                elesize += dictEntryMemUsage() + zmalloc_size(znode);
+                elesize += dictEntryMemUsage(NULL) + zmalloc_size(znode);
                 samples++;
                 znode = znode->level[0].forward;
             }
@@ -1052,7 +1052,7 @@ size_t objectComputeSize(robj *key, robj *o, size_t sample_size, int dbid) {
                 ele = dictGetKey(de);
                 ele2 = dictGetVal(de);
                 elesize += sdsZmallocSize(ele) + sdsZmallocSize(ele2);
-                elesize += dictEntryMemUsage();
+                elesize += dictEntryMemUsage(de);
                 samples++;
             }
             dictReleaseIterator(di);
@@ -1552,7 +1552,7 @@ NULL
             return;
         }
         size_t usage = objectComputeSize(c->argv[2], dictGetVal(de), samples, c->db->id);
-        usage += zmalloc_size(de);
+        usage += dictEntryMemUsage(de);
         addReplyLongLong(c, usage);
     } else if (!strcasecmp(c->argv[1]->ptr, "stats") && c->argc == 2) {
         struct serverMemOverhead *mh = getMemoryOverheadData();