| Message ID | 20190807143119.8360-4-jgross@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | enhance lock debugging | expand |
On 07.08.2019 16:31, Juergen Gross wrote: > --- a/xen/Kconfig.debug > +++ b/xen/Kconfig.debug > @@ -53,6 +53,7 @@ config SPINLOCK_DEBUG > > config LOCK_PROFILE > bool "Lock Profiling" > + select SPINLOCK_DEBUG > ---help--- > Lock profiling allows you to see how often locks are taken and blocked. > You can use serial console to print (and reset) using 'l' and 'L' In which case, for sensible user experience, the selected option should come after this one. The way it is now afaict there'll be a prompt for SPINLOCK_DEBUG, the user may say "no", just to find that because of saying "yes" here it'll be turned on anyway. Whereas with switched ordering there'll be no prompt for the debug option at all (again afaict) if the profiling option was set to "yes". Jan
On 08.08.19 09:09, Jan Beulich wrote: > On 07.08.2019 16:31, Juergen Gross wrote: >> --- a/xen/Kconfig.debug >> +++ b/xen/Kconfig.debug >> @@ -53,6 +53,7 @@ config SPINLOCK_DEBUG >> >> config LOCK_PROFILE >> bool "Lock Profiling" >> + select SPINLOCK_DEBUG >> ---help--- >> Lock profiling allows you to see how often locks are taken and blocked. >> You can use serial console to print (and reset) using 'l' and 'L' > > In which case, for sensible user experience, the selected > option should come after this one. The way it is now afaict > there'll be a prompt for SPINLOCK_DEBUG, the user may say > "no", just to find that because of saying "yes" here it'll > be turned on anyway. Whereas with switched ordering there'll > be no prompt for the debug option at all (again afaict) if > the profiling option was set to "yes". Reordering is fine with me. Juergen
diff --git a/xen/Kconfig.debug b/xen/Kconfig.debug index 5db3e7ec25..a7387f1630 100644 --- a/xen/Kconfig.debug +++ b/xen/Kconfig.debug @@ -53,6 +53,7 @@ config SPINLOCK_DEBUG config LOCK_PROFILE bool "Lock Profiling" + select SPINLOCK_DEBUG ---help--- Lock profiling allows you to see how often locks are taken and blocked. You can use serial console to print (and reset) using 'l' and 'L' diff --git a/xen/common/spinlock.c b/xen/common/spinlock.c index 16356ec9b7..5730076581 100644 --- a/xen/common/spinlock.c +++ b/xen/common/spinlock.c @@ -362,10 +362,13 @@ static void spinlock_profile_iterate(lock_profile_subfunc *sub, void *par) static void spinlock_profile_print_elem(struct lock_profile *data, int32_t type, int32_t idx, void *par) { - if ( type == LOCKPROF_TYPE_GLOBAL ) - printk("%s %s:\n", lock_profile_ancs[type].name, data->name); - else - printk("%s %d %s:\n", lock_profile_ancs[type].name, idx, data->name); + struct spinlock *lock = data->lock; + + printk("%s ", lock_profile_ancs[type].name); + if ( type != LOCKPROF_TYPE_GLOBAL ) + printk("%d ", idx); + printk("%s: addr=%p, lockval=%04x, cpu=%d\n", data->name, lock, + lock->tickets.head_tail, lock->debug.cpu); printk(" lock:%12"PRId64"(%08X:%08X), block:%12"PRId64"(%08X:%08X)\n", data->lock_cnt, (u32)(data->time_hold >> 32), (u32)data->time_hold, data->block_cnt, (u32)(data->time_block >> 32), diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c index 1680d078db..404d28a725 100644 --- a/xen/drivers/char/console.c +++ b/xen/drivers/char/console.c @@ -1167,7 +1167,9 @@ void panic(const char *fmt, ...) unsigned long flags; static DEFINE_SPINLOCK(lock); static char buf[128]; - + + spin_debug_disable(); + spinlock_profile_printall('\0'); debugtrace_dump(); /* Protects buf[] and ensure multi-line message prints atomically. */ diff --git a/xen/include/xen/spinlock.h b/xen/include/xen/spinlock.h index e3458f10dd..26891445fe 100644 --- a/xen/include/xen/spinlock.h +++ b/xen/include/xen/spinlock.h @@ -130,6 +130,7 @@ struct lock_profile_qhead { }; #define spin_lock_init_prof(s, l) spin_lock_init(&((s)->l)) #define lock_profile_register_struct(type, ptr, idx, print) #define lock_profile_deregister_struct(type, ptr) +#define spinlock_profile_printall(key) #endif
Print the lock profile data when the system crashes and add some more information for each lock data (lock address, cpu holding the lock). This is especially beneficial for watchdog triggered crashes in case of deadlocks. In order to have the cpu holding the lock available let the LOCK_PROFILE config option select SPINLOCK_DEBUG. As printing the lock profile data will make use of locking, too, we need to disable spinlock debugging before calling spinlock_profile_printall() from panic(). While at it remove a superfluous #ifdef CONFIG_LOCK_PROFILE. Signed-off-by: Juergen Gross <jgross@suse.com> --- xen/Kconfig.debug | 1 + xen/common/spinlock.c | 11 +++++++---- xen/drivers/char/console.c | 4 +++- xen/include/xen/spinlock.h | 1 + 4 files changed, 12 insertions(+), 5 deletions(-)