[PATCH] x86: combine printk()s in show_regs_common()

[PATCH] x86: combine printk()s in show_regs_common()

[Jan Beulich]

Printing a single character alone when there's an immediately following
printk() is pretty pointless (and wasteful).

Signed-off-by: Jan Beulich <jbeulich@novell.com>

---
 arch/x86/kernel/process.c |    9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

--- 2.6.38-rc5/arch/x86/kernel/process.c
+++ 2.6.38-rc5-x86-show-regs-fold-printks/arch/x86/kernel/process.c
@@ -110,12 +110,9 @@ void show_regs_common(void)
 		init_utsname()->release,
 		(int)strcspn(init_utsname()->version, " "),
 		init_utsname()->version);
-	printk(KERN_CONT " ");
-	printk(KERN_CONT "%s %s", vendor, product);
-	if (board) {
-		printk(KERN_CONT "/");
-		printk(KERN_CONT "%s", board);
-	}
+	printk(KERN_CONT " %s %s", vendor, product);
+	if (board)
+		printk(KERN_CONT "/%s", board);
 	printk(KERN_CONT "\n");
 }
 

Re: [PATCH] x86: combine printk()s in show_regs_common()

[Joe Perches]

On Thu, 2011-02-17 at 15:56 +0000, Jan Beulich wrote:
> Printing a single character alone when there's an immediately following
> printk() is pretty pointless (and wasteful).
> 
> Signed-off-by: Jan Beulich <jbeulich@novell.com>

Perhaps better still to use just one printk.

Signed-off-by: Joe Perches <joe@perches.com>
---
 arch/x86/kernel/process.c |   22 ++++++++++------------
 1 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index ff45541..0f43771 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -103,20 +103,18 @@ void show_regs_common(void)
 
 	/* Board Name is optional */
 	board = dmi_get_system_info(DMI_BOARD_NAME);
+	if (!board)
+		board = "";
 
 	printk(KERN_CONT "\n");
-	printk(KERN_DEFAULT "Pid: %d, comm: %.20s %s %s %.*s",
-		current->pid, current->comm, print_tainted(),
-		init_utsname()->release,
-		(int)strcspn(init_utsname()->version, " "),
-		init_utsname()->version);
-	printk(KERN_CONT " ");
-	printk(KERN_CONT "%s %s", vendor, product);
-	if (board) {
-		printk(KERN_CONT "/");
-		printk(KERN_CONT "%s", board);
-	}
-	printk(KERN_CONT "\n");
+	printk(KERN_DEFAULT "Pid: %d, comm: %.20s %s %s %.*s %s %s%s%s\n",
+	       current->pid, current->comm, print_tainted(),
+	       init_utsname()->release,
+	       (int)strcspn(init_utsname()->version, " "),
+	       init_utsname()->version,
+	       vendor, product,
+	       strlen(board) ? "/" : "",
+	       board);
 }
 
 void flush_thread(void)

[tip:x86/debug] x86: Combine printk()s in show_regs_common()

[tip-bot for Jan Beulich]

Commit-ID:  fd8fa4d3ddc4cc04ec8097e632b995d535c52beb
Gitweb:     http://git.kernel.org/tip/fd8fa4d3ddc4cc04ec8097e632b995d535c52beb
Author:     Jan Beulich <JBeulich@novell.com>
AuthorDate: Thu, 17 Feb 2011 15:56:58 +0000
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 18 Feb 2011 08:52:30 +0100

x86: Combine printk()s in show_regs_common()

Printing a single character alone when there's an immediately
following printk() is pretty pointless (and wasteful).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <4D5D535A0200007800032730@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/process.c |    9 +++------
 1 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index ff45541..99fa3ad 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -110,12 +110,9 @@ void show_regs_common(void)
 		init_utsname()->release,
 		(int)strcspn(init_utsname()->version, " "),
 		init_utsname()->version);
-	printk(KERN_CONT " ");
-	printk(KERN_CONT "%s %s", vendor, product);
-	if (board) {
-		printk(KERN_CONT "/");
-		printk(KERN_CONT "%s", board);
-	}
+	printk(KERN_CONT " %s %s", vendor, product);
+	if (board)
+		printk(KERN_CONT "/%s", board);
 	printk(KERN_CONT "\n");
 }
 

Re: [tip:x86/debug] x86: Combine printk()s in show_regs_common()

[Joe Perches]

On Fri, 2011-02-18 at 10:40 +0000, tip-bot for Jan Beulich wrote:
> Commit-ID:  fd8fa4d3ddc4cc04ec8097e632b995d535c52beb
> Gitweb:     http://git.kernel.org/tip/fd8fa4d3ddc4cc04ec8097e632b995d535c52beb
> Author:     Jan Beulich <JBeulich@novell.com>
> AuthorDate: Thu, 17 Feb 2011 15:56:58 +0000
> Committer:  Ingo Molnar <mingo@elte.hu>
> CommitDate: Fri, 18 Feb 2011 08:52:30 +0100
> 
> x86: Combine printk()s in show_regs_common()
> 
> Printing a single character alone when there's an immediately
> following printk() is pretty pointless (and wasteful).

Ingo, why did you choose to apply this patch instead of
the alternative one I posted on the same thread?

https://patchwork.kernel.org/patch/571641/

Re: [tip:x86/debug] x86: Combine printk()s in show_regs_common()

[Ingo Molnar]

* Joe Perches <joe@perches.com> wrote:

> On Fri, 2011-02-18 at 10:40 +0000, tip-bot for Jan Beulich wrote:
> > Commit-ID:  fd8fa4d3ddc4cc04ec8097e632b995d535c52beb
> > Gitweb:     http://git.kernel.org/tip/fd8fa4d3ddc4cc04ec8097e632b995d535c52beb
> > Author:     Jan Beulich <JBeulich@novell.com>
> > AuthorDate: Thu, 17 Feb 2011 15:56:58 +0000
> > Committer:  Ingo Molnar <mingo@elte.hu>
> > CommitDate: Fri, 18 Feb 2011 08:52:30 +0100
> > 
> > x86: Combine printk()s in show_regs_common()
> > 
> > Printing a single character alone when there's an immediately
> > following printk() is pretty pointless (and wasteful).
> 
> Ingo, why did you choose to apply this patch instead of
> the alternative one I posted on the same thread?

Your version:

	/* Board Name is optional */
	board = dmi_get_system_info(DMI_BOARD_NAME);
	if (!board)
		board = "";

	printk(KERN_CONT "\n");

	printk(KERN_DEFAULT "Pid: %d, comm: %.20s %s %s %.*s %s %s%s%s\n",
	       current->pid, current->comm, print_tainted(),
	       init_utsname()->release,
	       (int)strcspn(init_utsname()->version, " "),
	       init_utsname()->version,
	       vendor, product,
	       strlen(board) ? "/" : "",
	       board);

The 'board' fiddling and the strlen(board) check complicates things unnecessarily 
and makes the code hard to read. Jan's version was at least simple.

Something like this:

	/* Board Name is optional */
	board = dmi_get_system_info(DMI_BOARD_NAME);

	printk(KERN_CONT "\n");

	printk(KERN_DEFAULT "Pid: %d, comm: %.20s %s %s %.*s %s %s %s %s\n",
	       current->pid, current->comm, print_tainted(),
	       init_utsname()->release,
	       (int)strcspn(init_utsname()->version, " "),
	       init_utsname()->version,
	       vendor, product, board ? : "");

Would be easier to read and gives similarly useful output.

Thanks,

	Ingo

Re: [tip:x86/debug] x86: Combine printk()s in show_regs_common()

[Joe Perches]

On Fri, 2011-02-18 at 21:05 +0100, Ingo Molnar wrote:
> * Joe Perches <joe@perches.com> wrote:
> > Ingo, why did you choose to apply this patch instead of
> > the alternative one I posted on the same thread?
> Your version:
> 
> 	/* Board Name is optional */
> 	board = dmi_get_system_info(DMI_BOARD_NAME);
> 	if (!board)
> 		board = "";
> 
> 	printk(KERN_CONT "\n");
> 
> 	printk(KERN_DEFAULT "Pid: %d, comm: %.20s %s %s %.*s %s %s%s%s\n",
> 	       current->pid, current->comm, print_tainted(),
> 	       init_utsname()->release,
> 	       (int)strcspn(init_utsname()->version, " "),
> 	       init_utsname()->version,
> 	       vendor, product,
> 	       strlen(board) ? "/" : "",
> 	       board);
> 
> The 'board' fiddling and the strlen(board) check complicates things unnecessarily 
> and makes the code hard to read. Jan's version was at least simple.

Perhaps you should look at the surrounding code.
It's uses the same style as I chose for "board".

void show_regs_common(void)
{
	const char *vendor, *product, *board;

	vendor = dmi_get_system_info(DMI_SYS_VENDOR);
	if (!vendor)
		vendor = "";
	product = dmi_get_system_info(DMI_PRODUCT_NAME);
	if (!product)
		product = "";
...

> Something like this:
> 
> 	/* Board Name is optional */
> 	board = dmi_get_system_info(DMI_BOARD_NAME);
> 
> 	printk(KERN_CONT "\n");
> 
> 	printk(KERN_DEFAULT "Pid: %d, comm: %.20s %s %s %.*s %s %s %s %s\n",
> 	       current->pid, current->comm, print_tainted(),
> 	       init_utsname()->release,
> 	       (int)strcspn(init_utsname()->version, " "),
> 	       init_utsname()->version,
> 	       vendor, product, board ? : "");
> 
> Would be easier to read and gives similarly useful output.

It's a question of using identical output or
merely similar output.

cheers, Joe

Re: [tip:x86/debug] x86: Combine printk()s in show_regs_common()

[Ingo Molnar]

* Joe Perches <joe@perches.com> wrote:

> On Fri, 2011-02-18 at 21:05 +0100, Ingo Molnar wrote:
> > * Joe Perches <joe@perches.com> wrote:
> > > Ingo, why did you choose to apply this patch instead of
> > > the alternative one I posted on the same thread?
> > Your version:
> > 
> > 	/* Board Name is optional */
> > 	board = dmi_get_system_info(DMI_BOARD_NAME);
> > 	if (!board)
> > 		board = "";
> > 
> > 	printk(KERN_CONT "\n");
> > 
> > 	printk(KERN_DEFAULT "Pid: %d, comm: %.20s %s %s %.*s %s %s%s%s\n",
> > 	       current->pid, current->comm, print_tainted(),
> > 	       init_utsname()->release,
> > 	       (int)strcspn(init_utsname()->version, " "),
> > 	       init_utsname()->version,
> > 	       vendor, product,
> > 	       strlen(board) ? "/" : "",
> > 	       board);
> > 
> > The 'board' fiddling and the strlen(board) check complicates things unnecessarily 
> > and makes the code hard to read. Jan's version was at least simple.
> 
> Perhaps you should look at the surrounding code.
> It's uses the same style as I chose for "board".

Yes, i realize that, but the strlen() trick really looks weird.

And 'weird' is not something i like seeing in essential bug reporting code.

Thanks,

	Ingo