Hi Sergey, Thanks for the review.
On Tue, Apr 02, 2019 at 11:14:19AM +0900, Sergey Senozhatsky wrote: > On (04/01/19 18:48), Feng Tang wrote: > > diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c > > index 1fd45a8..58d9580 100644 > > --- a/arch/powerpc/kernel/traps.c > > +++ b/arch/powerpc/kernel/traps.c > > @@ -179,7 +179,7 @@ extern void panic_flush_kmsg_end(void) > > kmsg_dump(KMSG_DUMP_PANIC); > > bust_spinlocks(0); > > debug_locks_off(); > > - console_flush_on_panic(); > > + console_flush_on_panic(false); > > } > [..] > > @@ -277,7 +277,7 @@ void panic(const char *fmt, ...) > > * panic() is not being callled from OOPS. > > */ > > debug_locks_off(); > > - console_flush_on_panic(); > > + console_flush_on_panic(false); > [..] > > -void console_flush_on_panic(void) > > +void console_flush_on_panic(bool flush_all) > > { > > /* > > * If someone else is holding the console lock, trylock will fail > > @@ -2539,6 +2540,12 @@ void console_flush_on_panic(void) > > */ > > console_trylock(); > > console_may_schedule = 0; > > + > > + /* User may want to see all the printk messages on panic */ > > + if (flush_all) { > > + console_seq = log_first_seq; > > + console_idx = log_first_idx; > > + } > > console_unlock(); > > So my first thought was - let's not add a `bool flag', but instead add > an `enum' with clear flag names, e.g. DUMP_ALL/DUMP_PENDING, etc. Something > similar to what ftrace_dump(DUMP_ALL) does. And we already have panic_print > bit-mask and panic_print_sys_info(), which controls what we print when in > panic. So we can move console_flush_on_panic() to panic_print_sys_info() > and handle different types of console_flush_on_panic() there: > > --- > > diff --git a/kernel/panic.c b/kernel/panic.c > index 0ae0d7332f12..e142faaebbcd 100644 > --- a/kernel/panic.c > +++ b/kernel/panic.c > @@ -134,6 +134,11 @@ EXPORT_SYMBOL(nmi_panic); > > static void panic_print_sys_info(void) > { > + if (panic_print & PANIC_PRINT_REPLAY_LOGBUF) > + console_flush_on_panic(DUMP_ALL); > + else > + console_flush_on_panic(DUMP_PENDING); > + > if (panic_print & PANIC_PRINT_TASK_INFO) > show_state(); > > @@ -277,7 +282,6 @@ void panic(const char *fmt, ...) > * panic() is not being callled from OOPS. > */ > debug_locks_off(); > - console_flush_on_panic(); > > panic_print_sys_info(); > I guess this is what my 2/2 patch exactly does :) > --- > > After looking at this more - DUMP_ALL/DUMP_PENDING clearly depend > on panic_print. So... May be we can move panic_print_sys_info() to > printk.c, and for PANIC_PRINT_REPLAY_LOGBUF case just reset console > seq/idx (console seq/idx are internal to printk) before we > flush_on_panic. This way we would not need to modify > console_flush_on_panic() prototype at all. My thought is panic_print_sys_info() may be more related to panic, but I'm fine with either way. Thanks, Feng > > Let's hear from people. > > -ss