Re: [PATCH 2/7] powerpc/traps: Return early in show_signal_msg()
Hi, Christophe. On Wed, Jul 25, 2018 at 05:42:28PM +0200, LEROY Christophe wrote: > Murilo Opsfelder Araujo 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
Re: [PATCH 2/7] powerpc/traps: Return early in show_signal_msg()
Hi, Christophe. On Wed, Jul 25, 2018 at 05:42:28PM +0200, LEROY Christophe wrote: > Murilo Opsfelder Araujo 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
Re: [PATCH 2/7] powerpc/traps: Return early in show_signal_msg()
Murilo Opsfelder Araujo 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
---
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();
+}
+
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
Re: [PATCH 2/7] powerpc/traps: Return early in show_signal_msg()
Murilo Opsfelder Araujo 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
---
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();
+}
+
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
