| Message ID | 20180724192720.32417-3-muriloo@linux.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | powerpc: Modernize unhandled signals message | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | next/apply_patch Successfully applied |
| snowpatch_ozlabs/checkpatch | warning | Test checkpatch on branch next |
Murilo Opsfelder Araujo <muriloo@linux.ibm.com> a écrit : > Modify logic of show_signal_msg() to return early, if possible. Replace > printk_ratelimited() by printk() and a default rate limit burst to limit > displaying unhandled signals messages. Can you explain more the benefits of this change ? Christophe > > Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com> > --- > arch/powerpc/kernel/traps.c | 21 +++++++++++++++------ > 1 file changed, 15 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c > index cbd3dc365193..4faab4705774 100644 > --- a/arch/powerpc/kernel/traps.c > +++ b/arch/powerpc/kernel/traps.c > @@ -301,6 +301,13 @@ void user_single_step_siginfo(struct task_struct *tsk, > info->si_addr = (void __user *)regs->nip; > } > > +static bool show_unhandled_signals_ratelimited(void) > +{ > + static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL, > + DEFAULT_RATELIMIT_BURST); > + return show_unhandled_signals && __ratelimit(&rs); > +} > + > static void show_signal_msg(int signr, struct pt_regs *regs, int code, > unsigned long addr) > { > @@ -309,11 +316,12 @@ static void show_signal_msg(int signr, struct > pt_regs *regs, int code, > const char fmt64[] = KERN_INFO "%s[%d]: unhandled signal %d " \ > "at %016lx nip %016lx lr %016lx code %x\n"; > > - if (show_unhandled_signals && unhandled_signal(current, signr)) { > - printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32, > - current->comm, current->pid, signr, > - addr, regs->nip, regs->link, code); > - } > + if (!unhandled_signal(current, signr)) > + return; > + > + printk(regs->msr & MSR_64BIT ? fmt64 : fmt32, > + current->comm, current->pid, signr, > + addr, regs->nip, regs->link, code); > } > > void _exception_pkey(int signr, struct pt_regs *regs, int code, > @@ -326,7 +334,8 @@ void _exception_pkey(int signr, struct pt_regs > *regs, int code, > return; > } > > - show_signal_msg(signr, regs, code, addr); > + if (show_unhandled_signals_ratelimited()) > + show_signal_msg(signr, regs, code, addr); > > if (arch_irqs_disabled() && !arch_irq_disabled_regs(regs)) > local_irq_enable(); > -- > 2.17.1
Hi, Christophe. On Wed, Jul 25, 2018 at 05:42:28PM +0200, LEROY Christophe wrote: > Murilo Opsfelder Araujo <muriloo@linux.ibm.com> a écrit : > > > Modify logic of show_signal_msg() to return early, if possible. Replace > > printk_ratelimited() by printk() and a default rate limit burst to limit > > displaying unhandled signals messages. > > Can you explain more the benefits of this change ? Mainly is to improve readability of the function. The conditions to display the message were coupled together in one single `if` statement. Besides that, patch 5/7 adds a call to print_vma_addr(), which is not aware of any rate limit - it simply calls printk(). So splitting out the rate limit check outside show_signal_msg() makes it easier to the caller decide if it wants to respect a printk rate limit or not. Cheers Murilo
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index cbd3dc365193..4faab4705774 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -301,6 +301,13 @@ void user_single_step_siginfo(struct task_struct *tsk, info->si_addr = (void __user *)regs->nip; } +static bool show_unhandled_signals_ratelimited(void) +{ + static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL, + DEFAULT_RATELIMIT_BURST); + return show_unhandled_signals && __ratelimit(&rs); +} + static void show_signal_msg(int signr, struct pt_regs *regs, int code, unsigned long addr) { @@ -309,11 +316,12 @@ static void show_signal_msg(int signr, struct pt_regs *regs, int code, const char fmt64[] = KERN_INFO "%s[%d]: unhandled signal %d " \ "at %016lx nip %016lx lr %016lx code %x\n"; - if (show_unhandled_signals && unhandled_signal(current, signr)) { - printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32, - current->comm, current->pid, signr, - addr, regs->nip, regs->link, code); - } + if (!unhandled_signal(current, signr)) + return; + + printk(regs->msr & MSR_64BIT ? fmt64 : fmt32, + current->comm, current->pid, signr, + addr, regs->nip, regs->link, code); } void _exception_pkey(int signr, struct pt_regs *regs, int code, @@ -326,7 +334,8 @@ void _exception_pkey(int signr, struct pt_regs *regs, int code, return; } - show_signal_msg(signr, regs, code, addr); + if (show_unhandled_signals_ratelimited()) + show_signal_msg(signr, regs, code, addr); if (arch_irqs_disabled() && !arch_irq_disabled_regs(regs)) local_irq_enable();
Modify logic of show_signal_msg() to return early, if possible. Replace printk_ratelimited() by printk() and a default rate limit burst to limit displaying unhandled signals messages. Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com> --- arch/powerpc/kernel/traps.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-)