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: Pekka Paalanen <[EMAIL PROTECTED]>
---
arch/x86/kernel/mmiotrace/mmio-mod.c | 26 ++++++++++++++++----------
1 files changed, 16 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kernel/mmiotrace/mmio-mod.c
b/arch/x86/kernel/mmiotrace/mmio-mod.c
index 82ae920..f492b65 100644
--- a/arch/x86/kernel/mmiotrace/mmio-mod.c
+++ b/arch/x86/kernel/mmiotrace/mmio-mod.c
@@ -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;
--
1.5.3.7
--
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