x86: Cleanup NMI handling

[PATCH 9/9] x86/nmi: Improve NMI duration console print

Posted by Sohil Mehta 8 months, 3 weeks ago

Convert the last remaining printk() in nmi.c to pr_info(). Along with
it, use timespec macros to calculate the NMI handler duration.

Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
---
 arch/x86/kernel/nmi.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 59ed74ec010e..be93ec7255bf 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -119,12 +119,12 @@ static void nmi_check_duration(struct nmiaction *action, u64 duration)
 
 	action->max_duration = duration;
 
-	remainder_ns = do_div(duration, (1000 * 1000));
-	decimal_msecs = remainder_ns / 1000;
+	/* Convert duration from nsec to msec */
+	remainder_ns = do_div(duration, NSEC_PER_MSEC);
+	decimal_msecs = remainder_ns / NSEC_PER_USEC;
 
-	printk_ratelimited(KERN_INFO
-		"INFO: NMI handler (%ps) took too long to run: %lld.%03d msecs\n",
-		action->handler, duration, decimal_msecs);
+	pr_info_ratelimited("INFO: NMI handler (%ps) took too long to run: %lld.%03d msecs\n",
+			    action->handler, duration, decimal_msecs);
 }
 
 static int nmi_handle(unsigned int type, struct pt_regs *regs)
-- 
2.43.0

Re: [PATCH 9/9] x86/nmi: Improve NMI duration console print

Posted by Huang, Kai 8 months, 2 weeks ago

On Thu, 2025-03-27 at 23:46 +0000, Mehta, Sohil wrote:
> Convert the last remaining printk() in nmi.c to pr_info(). Along with
> it, use timespec macros to calculate the NMI handler duration.
> 
> Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>

I eventually figured out the reasons to use NSEC_PER_MSEC and NSEC_PER_USEC:

Reviewed-by: Kai Huang <kai.huang@intel.com>

> ---
>  arch/x86/kernel/nmi.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
> index 59ed74ec010e..be93ec7255bf 100644
> --- a/arch/x86/kernel/nmi.c
> +++ b/arch/x86/kernel/nmi.c
> @@ -119,12 +119,12 @@ static void nmi_check_duration(struct nmiaction *action, u64 duration)
>  
>  	action->max_duration = duration;
>  
> -	remainder_ns = do_div(duration, (1000 * 1000));
> -	decimal_msecs = remainder_ns / 1000;
> +	/* Convert duration from nsec to msec */
> +	remainder_ns = do_div(duration, NSEC_PER_MSEC);
> +	decimal_msecs = remainder_ns / NSEC_PER_USEC;
>  
> -	printk_ratelimited(KERN_INFO
> -		"INFO: NMI handler (%ps) took too long to run: %lld.%03d msecs\n",
> -		action->handler, duration, decimal_msecs);
> +	pr_info_ratelimited("INFO: NMI handler (%ps) took too long to run: %lld.%03d msecs\n",
> +			    action->handler, duration, decimal_msecs);
>  }
>  
>  static int nmi_handle(unsigned int type, struct pt_regs *regs)

[tip: x86/nmi] x86/nmi: Improve NMI duration console printouts

Posted by tip-bot2 for Sohil Mehta 8 months, 2 weeks ago

The following commit has been merged into the x86/nmi branch of tip:

Commit-ID:     f2e01dcf6df2d12e86c363ea9c37d53994d89dd6
Gitweb:        https://git.kernel.org/tip/f2e01dcf6df2d12e86c363ea9c37d53994d89dd6
Author:        Sohil Mehta <sohil.mehta@intel.com>
AuthorDate:    Thu, 27 Mar 2025 23:46:29 
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 01 Apr 2025 22:26:38 +02:00

x86/nmi: Improve NMI duration console printouts

Convert the last remaining printk() in nmi.c to pr_info(). Along with
it, use timespec macros to calculate the NMI handler duration.

Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Link: https://lore.kernel.org/r/20250327234629.3953536-10-sohil.mehta@intel.com
---
 arch/x86/kernel/nmi.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 59ed74e..be93ec7 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -119,12 +119,12 @@ static void nmi_check_duration(struct nmiaction *action, u64 duration)
 
 	action->max_duration = duration;
 
-	remainder_ns = do_div(duration, (1000 * 1000));
-	decimal_msecs = remainder_ns / 1000;
+	/* Convert duration from nsec to msec */
+	remainder_ns = do_div(duration, NSEC_PER_MSEC);
+	decimal_msecs = remainder_ns / NSEC_PER_USEC;
 
-	printk_ratelimited(KERN_INFO
-		"INFO: NMI handler (%ps) took too long to run: %lld.%03d msecs\n",
-		action->handler, duration, decimal_msecs);
+	pr_info_ratelimited("INFO: NMI handler (%ps) took too long to run: %lld.%03d msecs\n",
+			    action->handler, duration, decimal_msecs);
 }
 
 static int nmi_handle(unsigned int type, struct pt_regs *regs)