diff --git a/src/others/sysmon/lv_sysmon.c b/src/others/sysmon/lv_sysmon.c
index a26e828b8f..246706c5ef 100644
--- a/src/others/sysmon/lv_sysmon.c
+++ b/src/others/sysmon/lv_sysmon.c
@@ -271,10 +271,13 @@ static void mem_observer_cb(lv_observer_t * observer, lv_subject_t * subject)
     uint32_t used_size = mon->total_size - mon->free_size;;
     uint32_t used_kb = used_size / 1024;
     uint32_t used_kb_tenth = (used_size - (used_kb * 1024)) / 102;
+    uint32_t max_used_kb = mon->max_used / 1024;
+    uint32_t max_used_kb_tenth = (mon->max_used - (max_used_kb * 1024)) / 102;
     lv_label_set_text_fmt(label,
-                          "%"LV_PRIu32 ".%"LV_PRIu32 " kB, %d%%\n"
-                          "%d%% frag.",
+                          "%"LV_PRIu32 ".%"LV_PRIu32 " kB (%d%%)\n"
+                          "%"LV_PRIu32 ".%"LV_PRIu32 " kB max, %d%% frag.",
                           used_kb, used_kb_tenth, mon->used_pct,
+                          max_used_kb, max_used_kb_tenth,
                           mon->frag_pct);
 }
 
diff --git a/src/stdlib/builtin/lv_mem_core_builtin.c b/src/stdlib/builtin/lv_mem_core_builtin.c
index c8f3233e32..b7b707de35 100644
--- a/src/stdlib/builtin/lv_mem_core_builtin.c
+++ b/src/stdlib/builtin/lv_mem_core_builtin.c
@@ -141,10 +141,13 @@ void * lv_malloc_core(size_t size)
 #if LV_USE_OS
     lv_mutex_lock(&state.mutex);
 #endif
-    state.cur_used += size;
-    state.max_used = LV_MAX(state.cur_used, state.max_used);
     void * p = lv_tlsf_malloc(state.tlsf, size);
 
+    if(p) {
+        state.cur_used += lv_tlsf_block_size(p);
+        state.max_used = LV_MAX(state.cur_used, state.max_used);
+    }
+
 #if LV_USE_OS
     lv_mutex_unlock(&state.mutex);
 #endif
@@ -157,8 +160,14 @@ void * lv_realloc_core(void * p, size_t new_size)
     lv_mutex_lock(&state.mutex);
 #endif
 
+    size_t old_size = lv_tlsf_block_size(p);
     void * p_new = lv_tlsf_realloc(state.tlsf, p, new_size);
 
+    if(p_new) {
+        state.cur_used -= old_size;
+        state.cur_used += lv_tlsf_block_size(p_new);
+        state.max_used = LV_MAX(state.cur_used, state.max_used);
+    }
 #if LV_USE_OS
     lv_mutex_unlock(&state.mutex);
 #endif
@@ -175,7 +184,8 @@ void lv_free_core(void * p)
 #if LV_MEM_ADD_JUNK
     lv_memset(p, 0xbb, lv_tlsf_block_size(data));
 #endif
-    size_t size = lv_tlsf_free(state.tlsf, p);
+    size_t size = lv_tlsf_block_size(p);
+    lv_tlsf_free(state.tlsf, p);
     if(state.cur_used > size) state.cur_used -= size;
     else state.cur_used = 0;