On Fri, 2008-06-20 at 01:26 -0400, Len Brown wrote:
> A GPE storm is a bug.
>
> I think the mechanism in the previous patch to deal with that
> failure is sufficient. I don't like embedding heuristic policy
> into the kernel all for the benefit of broken systems.
> We'll never know if the heuristic is correct, and there
> is always the risk that we impact an otherwise working system.
>
> User-space can detect a GPE storm via /proc/interrupts
> and /sys/firmware/acpi/interrupts, and handle it that way.
> (and then we can debug the root cause of the failure,
> rather than have it hidden by the kernel)
Agree. Just keep this as a "debug patch".
Lin Ming
>
> -Len
>
>
> On Fri, 20 Jun 2008, Zhang Rui wrote:
>
> > From: Ling Ming <ming.m.lin@xxxxxxxxx>
> >
> > Dectect GPE storm and disable a certain GPE if needed.
> >
> > Introduce a new module parameter "debug_gpe_storm" as a runtime switch to
> > enable/disable this mechanism. The default value is TRUE, user can
> > "echo 0 > /sys/modules/acpi/parameters/debug_gpe_storm" to disable it.
> >
> > Note: we try to disable a GPE if it's fired more than 1000 times in a second.
> > And this 1000/s is just a wild guess currently. Need more tests to get a
> > proper value.
> >
> > Signed-off-by: Lin Ming <ming.m.lin@xxxxxxxxx>
> > Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> > ---
> > drivers/acpi/events/evgpe.c | 15 +++++++++++-
> > drivers/acpi/system.c | 55 ++++++++++++++++++++++++++++++++++++++++----
> > include/acpi/acpiosxf.h | 2 -
> > 3 files changed, 65 insertions(+), 7 deletions(-)
> >
> > Index: linux-2.6/drivers/acpi/events/evgpe.c
> > ===================================================================
> > --- linux-2.6.orig/drivers/acpi/events/evgpe.c 2008-06-20 09:27:00.000000000 +0800
> > +++ linux-2.6/drivers/acpi/events/evgpe.c 2008-06-20 09:34:32.000000000 +0800
> > @@ -623,7 +623,20 @@
> >
> > ACPI_FUNCTION_TRACE(ev_gpe_dispatch);
> >
> > - acpi_os_gpe_count(gpe_number);
> > + if (acpi_os_gpe_storm_detect(gpe_number)) {
> > + /*
> > + * GPE storm detected, disable it automatically
> > + * To disable gpe storm detection:
> > + * "echo 0 > /sys/module/acpi/parameters/debug_gpe_storm"
> > + */
> > + acpi_status status = acpi_ev_disable_gpe(gpe_event_info);
> > + if (ACPI_FAILURE(status)) {
> > + ACPI_EXCEPTION((AE_INFO, status,
> > + "Unable to disable GPE[%2X]", gpe_number));
> > + }
> > +
> > + return_UINT32(ACPI_INTERRUPT_NOT_HANDLED);
> > + }
> >
> > /*
> > * If edge-triggered, clear the GPE status bit now. Note that
> > Index: linux-2.6/drivers/acpi/system.c
> > ===================================================================
> > --- linux-2.6.orig/drivers/acpi/system.c 2008-06-20 09:27:00.000000000 +0800
> > +++ linux-2.6/drivers/acpi/system.c 2008-06-20 09:34:32.000000000 +0800
> > @@ -168,9 +168,14 @@
> > #define NUM_COUNTERS_EXTRA 3
> >
> > #define ACPI_EVENT_VALID 0x01
> > +#define GPE_STORM_INTERVAL HZ
> > +#define GPE_STORM_THRESHOLD 1000
> > +
> > struct event_counter {
> > u32 count;
> > u32 flags;
> > + u32 storm;
> > + unsigned long last_time;
> > };
> >
> > static struct event_counter *all_counters;
> > @@ -263,20 +268,60 @@
> > return;
> > }
> >
> > -void acpi_os_gpe_count(u32 gpe_number)
> > +/*
> > + * acpi_gbl_gpe_lock is already acquired in acpi_ev_gpe_detect
> > + */
> > +int check_gpe_storm(u32 gpe_number)
> > {
> > + struct event_counter *gpe_counter;
> > +
> > + if (gpe_number >= num_gpes)
> > + return 0;
> > +
> > + gpe_counter = &all_counters[gpe_number];
> > +
> > + if (time_after(jiffies, gpe_counter->last_time + GPE_STORM_INTERVAL)) {
> > + gpe_counter->storm = 0;
> > + gpe_counter->last_time = jiffies;
> > + }
> > +
> > + gpe_counter->storm++;
> > + if (gpe_counter->storm > GPE_STORM_THRESHOLD) {
> > + printk(KERN_WARNING "GPE[%2X] storm detected,"
> > + "%d interrupts in %d milliseconds.\n",
> > + gpe_number, gpe_counter->storm, GPE_STORM_INTERVAL);
> > + gpe_counter->storm = 0;
> > + gpe_counter->last_time = jiffies;
> > +
> > + return 1;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int debug_gpe_storm = 1;
> > +module_param(debug_gpe_storm, bool, 0644);
> > +
> > +int acpi_os_gpe_storm_detect(u32 gpe_number)
> > +{
> > + int storm = 0;
> > +
> > acpi_gpe_count++;
> >
> > if (!all_counters)
> > - return;
> > + return storm;
> >
> > - if (gpe_number < num_gpes)
> > + if (gpe_number < num_gpes) {
> > all_counters[gpe_number].count++;
> > +
> > + /* If debug_gpe_storm enabled, check gpe storm */
> > + if (debug_gpe_storm)
> > + storm = check_gpe_storm(gpe_number);
> > + }
> > else
> > all_counters[num_gpes + ACPI_NUM_FIXED_EVENTS + COUNT_ERROR].
> > count++;
> > -
> > - return;
> > + return storm;
> > }
> >
> > void acpi_os_fixed_event_count(u32 event_number)
> > Index: linux-2.6/include/acpi/acpiosxf.h
> > ===================================================================
> > --- linux-2.6.orig/include/acpi/acpiosxf.h 2008-06-20 09:27:00.000000000 +0800
> > +++ linux-2.6/include/acpi/acpiosxf.h 2008-06-20 09:34:32.000000000 +0800
> > @@ -181,7 +181,7 @@
> > acpi_status
> > acpi_os_remove_interrupt_handler(u32 gsi, acpi_osd_handler service_routine);
> >
> > -void acpi_os_gpe_count(u32 gpe_number);
> > +int acpi_os_gpe_storm_detect(u32 gpe_number);
> > void acpi_os_fixed_event_count(u32 fixed_event_number);
> >
> > /*
> >
> >
--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
