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/**
* Copyright (C) ARM Limited 2010-2012. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include "gator.h"
#include <trace/events/block.h>
#define BLOCK_RQ_WR 0
#define BLOCK_RQ_RD 1
#define BLOCK_TOTAL (BLOCK_RQ_RD+1)
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 36)
#define EVENTWRITE REQ_RW
#else
#define EVENTWRITE REQ_WRITE
#endif
static ulong block_rq_wr_enabled;
static ulong block_rq_rd_enabled;
static ulong block_rq_wr_key;
static ulong block_rq_rd_key;
static DEFINE_PER_CPU(int[BLOCK_TOTAL], blockCnt);
static DEFINE_PER_CPU(int[BLOCK_TOTAL * 2], blockGet);
static DEFINE_PER_CPU(bool, new_data_avail);
GATOR_DEFINE_PROBE(block_rq_complete, TP_PROTO(struct request_queue *q, struct request *rq))
{
unsigned long flags;
int write, size;
int cpu = smp_processor_id();
if (!rq)
return;
write = rq->cmd_flags & EVENTWRITE;
size = rq->resid_len;
if (!size)
return;
// disable interrupts to synchronize with gator_events_block_read()
// spinlocks not needed since percpu buffers are used
local_irq_save(flags);
if (write)
per_cpu(blockCnt, cpu)[BLOCK_RQ_WR] += size;
else
per_cpu(blockCnt, cpu)[BLOCK_RQ_RD] += size;
local_irq_restore(flags);
per_cpu(new_data_avail, cpu) = true;
}
static int gator_events_block_create_files(struct super_block *sb, struct dentry *root)
{
struct dentry *dir;
/* block_complete_wr */
dir = gatorfs_mkdir(sb, root, "Linux_block_rq_wr");
if (!dir) {
return -1;
}
gatorfs_create_ulong(sb, dir, "enabled", &block_rq_wr_enabled);
gatorfs_create_ro_ulong(sb, dir, "key", &block_rq_wr_key);
/* block_complete_rd */
dir = gatorfs_mkdir(sb, root, "Linux_block_rq_rd");
if (!dir) {
return -1;
}
gatorfs_create_ulong(sb, dir, "enabled", &block_rq_rd_enabled);
gatorfs_create_ro_ulong(sb, dir, "key", &block_rq_rd_key);
return 0;
}
static int gator_events_block_start(void)
{
int cpu;
for_each_present_cpu(cpu)
per_cpu(new_data_avail, cpu) = true;
// register tracepoints
if (block_rq_wr_enabled || block_rq_rd_enabled)
if (GATOR_REGISTER_TRACE(block_rq_complete))
goto fail_block_rq_exit;
pr_debug("gator: registered block event tracepoints\n");
return 0;
// unregister tracepoints on error
fail_block_rq_exit:
pr_err("gator: block event tracepoints failed to activate, please verify that tracepoints are enabled in the linux kernel\n");
return -1;
}
static void gator_events_block_stop(void)
{
if (block_rq_wr_enabled || block_rq_rd_enabled)
GATOR_UNREGISTER_TRACE(block_rq_complete);
pr_debug("gator: unregistered block event tracepoints\n");
block_rq_wr_enabled = 0;
block_rq_rd_enabled = 0;
}
static int gator_events_block_read(int **buffer)
{
unsigned long flags;
int len, value, cpu, data = 0;
cpu = smp_processor_id();
if (per_cpu(new_data_avail, cpu) == false)
return 0;
per_cpu(new_data_avail, cpu) = false;
len = 0;
if (block_rq_wr_enabled) {
local_irq_save(flags);
value = per_cpu(blockCnt, cpu)[BLOCK_RQ_WR];
per_cpu(blockCnt, cpu)[BLOCK_RQ_WR] = 0;
local_irq_restore(flags);
per_cpu(blockGet, cpu)[len++] = block_rq_wr_key;
per_cpu(blockGet, cpu)[len++] = value;
data += value;
}
if (block_rq_rd_enabled) {
local_irq_save(flags);
value = per_cpu(blockCnt, cpu)[BLOCK_RQ_RD];
per_cpu(blockCnt, cpu)[BLOCK_RQ_RD] = 0;
local_irq_restore(flags);
per_cpu(blockGet, cpu)[len++] = block_rq_rd_key;
per_cpu(blockGet, cpu)[len++] = value;
data += value;
}
if (data != 0)
per_cpu(new_data_avail, cpu) = true;
if (buffer)
*buffer = per_cpu(blockGet, cpu);
return len;
}
static struct gator_interface gator_events_block_interface = {
.create_files = gator_events_block_create_files,
.start = gator_events_block_start,
.stop = gator_events_block_stop,
.read = gator_events_block_read,
};
int gator_events_block_init(void)
{
block_rq_wr_enabled = 0;
block_rq_rd_enabled = 0;
block_rq_wr_key = gator_events_get_key();
block_rq_rd_key = gator_events_get_key();
return gator_events_install(&gator_events_block_interface);
}
gator_events_init(gator_events_block_init);
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