The patch titled
add touch_all_softlockup_watchdogs()
has been added to the -mm tree. Its filename is
add-touch_all_softlockup_watchdogs.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: add touch_all_softlockup_watchdogs()
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Add touch_all_softlockup_watchdogs() to allow the softlockup watchdog
timers on all cpus to be updated. This is used to prevent sysrq-t from
generating a spurious watchdog message when generating lots of output.
Softlockup watchdogs use sched_clock() as its timebase, which is inherently
per-cpu (at least, when it is measuring unstolen time). Because of this,
it isn't possible for one CPU to directly update the other CPU's timers,
but it is possible to tell the other CPUs to do update themselves
appropriately.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Acked-by: Chris Lalancette <clalance@xxxxxxxxxx>
Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Rick Lindsley <ricklind@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/sched.h | 4 ++++
kernel/sched.c | 2 ++
kernel/softlockup.c | 15 +++++++++++++--
3 files changed, 19 insertions(+), 2 deletions(-)
diff -puN include/linux/sched.h~add-touch_all_softlockup_watchdogs include/linux/sched.h
--- a/include/linux/sched.h~add-touch_all_softlockup_watchdogs
+++ a/include/linux/sched.h
@@ -226,6 +226,7 @@ extern void scheduler_tick(void);
extern void softlockup_tick(void);
extern void spawn_softlockup_task(void);
extern void touch_softlockup_watchdog(void);
+extern void touch_all_softlockup_watchdogs(void);
#else
static inline void softlockup_tick(void)
{
@@ -236,6 +237,9 @@ static inline void spawn_softlockup_task
static inline void touch_softlockup_watchdog(void)
{
}
+static inline void touch_all_softlockup_watchdogs(void)
+{
+}
#endif
diff -puN kernel/sched.c~add-touch_all_softlockup_watchdogs kernel/sched.c
--- a/kernel/sched.c~add-touch_all_softlockup_watchdogs
+++ a/kernel/sched.c
@@ -4750,6 +4750,8 @@ void show_state_filter(unsigned long sta
show_task(p);
} while_each_thread(g, p);
+ touch_all_softlockup_watchdogs();
+
read_unlock(&tasklist_lock);
/*
* Only show locks if all tasks are dumped:
diff -puN kernel/softlockup.c~add-touch_all_softlockup_watchdogs kernel/softlockup.c
--- a/kernel/softlockup.c~add-touch_all_softlockup_watchdogs
+++ a/kernel/softlockup.c
@@ -50,6 +50,16 @@ void touch_softlockup_watchdog(void)
}
EXPORT_SYMBOL(touch_softlockup_watchdog);
+void touch_all_softlockup_watchdogs(void)
+{
+ int cpu;
+
+ /* Cause each CPU to re-update its timestamp rather than complain */
+ for_each_online_cpu(cpu)
+ per_cpu(touch_timestamp, cpu) = 0;
+}
+EXPORT_SYMBOL(touch_all_softlockup_watchdogs);
+
/*
* This callback runs from the timer interrupt, and checks
* whether the watchdog thread has hung or not:
@@ -61,9 +71,10 @@ void softlockup_tick(void)
unsigned long print_timestamp;
unsigned long now;
- /* watchdog task hasn't updated timestamp yet */
- if (touch_timestamp == 0)
+ if (touch_timestamp == 0) {
+ touch_softlockup_watchdog();
return;
+ }
print_timestamp = per_cpu(print_timestamp, this_cpu);
_
Patches currently in -mm which might be from jeremy@xxxxxxxx are
revert-x86_64-mm-account-for-module-percpu-space-separately-from-kernel-percpu.patch
add-apply_to_page_range-which-applies-a-function-to-a-pte-range.patch
rename-the-parainstructions-symbols-to-be-consistent-with-the-others.patch
rename-the-parainstructions-symbols-to-be-consistent-with-the-others-fix.patch
allow-boot-time-disable-of-paravirt_ops-patching.patch
i386-map-enough-initial-memory-to-create-lowmem-mappings.patch
i386-map-enough-initial-memory-to-create-lowmem-mappings-fix.patch
mm-only-i386-for-debugging-make-the-initial-page-table-setup-less-forgiving.patch
maps2-uninline-some-functions-in-the-page-walker.patch
maps2-eliminate-the-pmd_walker-struct-in-the-page-walker.patch
maps2-remove-vma-from-args-in-the-page-walker.patch
maps2-propagate-errors-from-callback-in-page-walker.patch
maps2-add-callbacks-for-each-level-to-page-walker.patch
maps2-move-the-page-walker-code-to-lib.patch
maps2-move-the-page-walker-code-to-lib-fix.patch
maps2-simplify-interdependence-of-proc-pid-maps-and-smaps.patch
maps2-move-clear_refs-code-to-task_mmuc.patch
maps2-regroup-task_mmu-by-interface.patch
maps2-make-proc-pid-smaps-optional-under-config_embedded.patch
maps2-make-proc-pid-clear_refs-option-under-config_embedded.patch
maps2-add-proc-pid-pagemap-interface.patch
maps2-add-proc-kpagemap-interface.patch
fixes-and-cleanups-for-earlyprintk-aka-boot-console.patch
ignore-stolen-time-in-the-softlockup-watchdog.patch
ignore-stolen-time-in-the-softlockup-watchdog-fix.patch
add-touch_all_softlockup_watchdogs.patch
clean-up-elf-note-generation.patch
deflate-stack-usage-in-lib-inflatec.patch
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