diff options
| author | Pekka Paalanen <pq@iki.fi> | 2008-05-12 21:20:56 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2008-05-24 11:21:39 +0200 |
| commit | fe1ffafa80f6673101c6560c2bacfe3df10372ee (patch) | |
| tree | 15391f0e992a4b149270a12fc861dd5353980318 | |
| parent | 75bb88350e0501b3cf5ac096a1008757844414a9 (diff) | |
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: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | 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 e43947d218a5..0019dcdf6158 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; |