/*
* Copyright (c) 2020 Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* $Id: //eng/vdo-releases/aluminum/src/c++/vdo/kernel/ktrace.h#1 $
*/
#ifndef KTRACE_H
#define KTRACE_H
#include <linux/device-mapper.h>
#include "common.h"
#include "trace.h"
struct kernelLayer;
struct kvio;
// Implement event sampling once per N.
typedef struct {
unsigned int interval;
unsigned int tick;
spinlock_t lock;
} SampleCounter;
/**
* Flag indicating whether newly created VDO devices should record trace info.
**/
extern bool traceRecording;
/**
* Updates the counter state and returns true once each time the
* sampling interval is reached.
*
* @param counter The sampling counter info
*
* @return whether to do sampling on this invocation
**/
bool sampleThisOne(SampleCounter *counter);
/**
* Initialize trace data in the KernelLayer
*
* @param layer The KernelLayer
*
* @return VDO_SUCCESS, or an error code
**/
int traceKernelLayerInit(struct kernelLayer *layer);
/**
* Initialize the mutex used when logging latency tracing data.
**/
void initializeTraceLoggingOnce(void);
/**
* Allocate a trace buffer
*
* @param layer The KernelLayer
* @param tracePointer The trace buffer is returned here
*
* @return VDO_SUCCESS or an error code
**/
int allocTraceFromPool(struct kernelLayer *layer, Trace **tracePointer);
/**
* Free a trace buffer
*
* @param layer The KernelLayer
* @param trace The trace buffer
**/
void freeTraceToPool(struct kernelLayer *layer, Trace *trace);
/**
* Log the trace at kvio freeing time
*
* @param kvio The kvio structure
**/
void logKvioTrace(struct kvio *kvio);
#endif /* KTRACE_H */