Commit fe1ffafa authored by Pekka Paalanen's avatar Pekka Paalanen Committed by Thomas Gleixner

x86 mmiotrace: fix relay-buffer-full flag for SMP

Relay has per-cpu buffers, but mmiotrace was using only a single flag
for detecting buffer full/not-full transitions. The new code makes
this per-cpu and actually counts missed events.
Signed-off-by: default avatarPekka Paalanen <pq@iki.fi>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 75bb8835
......@@ -29,6 +29,7 @@
#include <asm/pgtable.h>
#include <linux/mmiotrace.h>
#include <asm/e820.h> /* for ISA_START_ADDRESS */
#include <asm/atomic.h>
#include "kmmio.h"
#include "pf_in.h"
......@@ -47,9 +48,13 @@ struct trap_reason {
int active_traces;
};
/* Accessed per-cpu. */
static struct trap_reason pf_reason[NR_CPUS];
static struct mm_io_header_rw cpu_trace[NR_CPUS];
/* Access to this is not per-cpu. */
static atomic_t dropped[NR_CPUS];
static struct file_operations mmio_fops = {
.owner = THIS_MODULE,
};
......@@ -57,7 +62,6 @@ static struct file_operations mmio_fops = {
static const size_t subbuf_size = 256*1024;
static struct rchan *chan;
static struct dentry *dir;
static int suspended; /* XXX should this be per cpu? */
static struct proc_dir_entry *proc_marker_file;
/* module parameters */
......@@ -269,19 +273,21 @@ static void post(struct kmmio_probe *p, unsigned long condition,
static int subbuf_start_handler(struct rchan_buf *buf, void *subbuf,
void *prev_subbuf, size_t prev_padding)
{
unsigned int cpu = buf->cpu;
atomic_t *drop = &dropped[cpu];
int count;
if (relay_buf_full(buf)) {
if (!suspended) {
suspended = 1;
printk(KERN_ERR MODULE_NAME
": cpu %d buffer full!!!\n",
smp_processor_id());
if (atomic_inc_return(drop) == 1) {
printk(KERN_ERR MODULE_NAME ": cpu %d buffer full!\n",
cpu);
}
return 0;
} else if (suspended) {
suspended = 0;
} else if ((count = atomic_read(drop))) {
printk(KERN_ERR MODULE_NAME
": cpu %d buffer no longer full.\n",
smp_processor_id());
": cpu %d buffer no longer full, "
"missed %d events.\n",
cpu, count);
atomic_sub(count, drop);
}
return 1;
......
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