[memory-infra] Implement peak detection logic

base/trace_event/memory_dump_scheduler.h

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_TRACE_EVENT_MEMORY_DUMP_SCHEDULER_H
 #define BASE_TRACE_EVENT_MEMORY_DUMP_SCHEDULER_H
 
 #include "base/base_export.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
@@ skipping 50 matching lines @@
     uint32_t light_dumps_rate;
     uint32_t heavy_dumps_rate;
 
     uint32_t light_dump_period_ms;
     uint32_t heavy_dump_period_ms;
 
     DISALLOW_COPY_AND_ASSIGN(PeriodicTriggerState);
   };
 
   struct PollingTriggerState {
+    static const uint32_t kMaxNumMemorySamples = 50;
+
     explicit PollingTriggerState(
         scoped_refptr<SingleThreadTaskRunner> polling_task_runner);
     ~PollingTriggerState();
 
     bool is_configured;
     bool is_polling_enabled;
     MemoryDumpLevelOfDetail level_of_detail;
 
     scoped_refptr<SingleThreadTaskRunner> polling_task_runner;
     uint32_t polling_interval_ms;
 
     // Minimum numer of polls after the last dump at which next dump can be
     // triggered.
     int min_polls_between_dumps;
     int num_polls_from_last_dump;
 
     uint64_t last_dump_memory_total;
+    int64_t memory_increase_threshold;
+    uint64_t last_memory_totals_kb[kMaxNumMemorySamples];
+    uint32_t last_memory_totals_kb_index;
 
     DISALLOW_COPY_AND_ASSIGN(PollingTriggerState);
   };
 
   // Helper to set polling disabled on the polling thread.
   void DisablePolling();
 
   // Periodically called by the timer.
   void RequestPeriodicGlobalDump();
 
   // Called for polling memory usage and trigger dumps if peak is detected.
   void PollMemoryOnPollingThread();
 
   // Returns true if peak memory value is detected.
   bool ShouldTriggerDump(uint64_t current_memory_total);
 
+  // Helper to detect peaks in memory usage.
+  bool IsCurrentSamplePeak(uint64_t current_memory_total);
+
   // Must be set before enabling tracing.
   static void SetPollingIntervalForTesting(uint32_t interval);
 
   // True if periodic dumping is enabled.
   bool IsPeriodicTimerRunningForTesting();
 
   MemoryDumpManager* mdm_;
 
   PeriodicTriggerState periodic_state_;
   PollingTriggerState polling_state_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryDumpScheduler);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_MEMORY_DUMP_SCHEDULER_H