[01/13] seq_file: rewrite seq_puts() in terms of seq_write()
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Message ID 20180827231503.26899-1-adobriyan@gmail.com
State New, archived
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  • [01/13] seq_file: rewrite seq_puts() in terms of seq_write()
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Commit Message

Alexey Dobriyan Aug. 27, 2018, 11:14 p.m. UTC
Space savings -- 42 bytes!

	seq_puts	71      29     [-42]

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
 fs/seq_file.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

Comments

Joe Perches Aug. 28, 2018, 6:24 p.m. UTC | #1
On Tue, 2018-08-28 at 02:14 +0300, Alexey Dobriyan wrote:
> Space savings -- 42 bytes!
> 
> 	seq_puts	71      29     [-42]
> 
> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> ---
>  fs/seq_file.c | 9 +--------
>  1 file changed, 1 insertion(+), 8 deletions(-)
> 
> diff --git a/fs/seq_file.c b/fs/seq_file.c
> index 1dea7a8a5255..0c282a88a896 100644
> --- a/fs/seq_file.c
> +++ b/fs/seq_file.c
> @@ -653,14 +653,7 @@ EXPORT_SYMBOL(seq_putc);
>  
>  void seq_puts(struct seq_file *m, const char *s)
>  {
> -	int len = strlen(s);
> -
> -	if (m->count + len >= m->size) {
> -		seq_set_overflow(m);
> -		return;
> -	}
> -	memcpy(m->buf + m->count, s, len);
> -	m->count += len;
> +	seq_write(m, s, strlen(s));
>  }
>  EXPORT_SYMBOL(seq_puts);
>  

If execution speed is really an issue, as
almost all of the uses are for const strings,
why not use a #define and avoid the runtime
cost of strlen where possible.
Joe Perches Aug. 28, 2018, 8:48 p.m. UTC | #2
On Tue, 2018-08-28 at 11:24 -0700, Joe Perches wrote:
> On Tue, 2018-08-28 at 02:14 +0300, Alexey Dobriyan wrote:
> > Space savings -- 42 bytes!
> > 
> > 	seq_puts	71      29     [-42]
> > 
> > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> > ---
> >  fs/seq_file.c | 9 +--------
> >  1 file changed, 1 insertion(+), 8 deletions(-)
> > 
> > diff --git a/fs/seq_file.c b/fs/seq_file.c
> > index 1dea7a8a5255..0c282a88a896 100644
> > --- a/fs/seq_file.c
> > +++ b/fs/seq_file.c
> > @@ -653,14 +653,7 @@ EXPORT_SYMBOL(seq_putc);
> >  
> >  void seq_puts(struct seq_file *m, const char *s)
> >  {
> > -	int len = strlen(s);
> > -
> > -	if (m->count + len >= m->size) {
> > -		seq_set_overflow(m);
> > -		return;
> > -	}
> > -	memcpy(m->buf + m->count, s, len);
> > -	m->count += len;
> > +	seq_write(m, s, strlen(s));
> >  }
> >  EXPORT_SYMBOL(seq_puts);
> >  
> 
> If execution speed is really an issue, as
> almost all of the uses are for const strings,
> why not use a #define and avoid the runtime
> cost of strlen where possible.

fyi: an x86-64 defconfig increases < .5 kb and
presumably is faster for most all seq_puts uses

$ size vmlinux.new vmlinux.old
   text	   data	    bss	    dec	    hex	
filename
17342316	4982128	 999628	23324072	163e5a8	
vmlinux.new
17341857	4982128	 999628	23323613	163e3dd	
vmlinux.old

with
---
 fs/seq_file.c            | 13 -------------
 include/linux/seq_file.h |  2 +-
 2 files changed, 1 insertion(+), 14 deletions(-)

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 1dea7a8a5255..97d474b6788e 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -651,19 +651,6 @@ void seq_putc(struct seq_file *m, char c)
 }
 EXPORT_SYMBOL(seq_putc);
 
-void seq_puts(struct seq_file *m, const char *s)
-{
-	int len = strlen(s);
-
-	if (m->count + len >= m->size) {
-		seq_set_overflow(m);
-		return;
-	}
-	memcpy(m->buf + m->count, s, len);
-	m->count += len;
-}
-EXPORT_SYMBOL(seq_puts);
-
 /**
  * A helper routine for putting decimal numbers without rich format of printf().
  * only 'unsigned long long' is supported.
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index a121982af0f5..722028805df6 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -117,7 +117,7 @@ void seq_vprintf(struct seq_file *m, const char *fmt, va_list args);
 __printf(2, 3)
 void seq_printf(struct seq_file *m, const char *fmt, ...);
 void seq_putc(struct seq_file *m, char c);
-void seq_puts(struct seq_file *m, const char *s);
+#define seq_puts(m, s) seq_write(m, s, strlen(s))
 void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
 			       unsigned long long num, unsigned int width);
 void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
Alexey Dobriyan Sept. 3, 2018, 2:17 p.m. UTC | #3
Joe Perches wrote:

> > If execution speed is really an issue, as
> > almost all of the uses are for const strings,
> > why not use a #define and avoid the runtime
> > cost of strlen where possible.
> 
> fyi: an x86-64 defconfig increases < .5 kb and
> presumably is faster for most all seq_puts uses

> -void seq_puts(struct seq_file *m, const char *s);
> +#define seq_puts(m, s) seq_write(m, s, strlen(s))

I don't know, seq_puts() patch was last minute observation.
It is independent of _print_integer() stuff.

Your version should be "static inline" of course.

Patch
diff mbox series

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 1dea7a8a5255..0c282a88a896 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -653,14 +653,7 @@  EXPORT_SYMBOL(seq_putc);
 
 void seq_puts(struct seq_file *m, const char *s)
 {
-	int len = strlen(s);
-
-	if (m->count + len >= m->size) {
-		seq_set_overflow(m);
-		return;
-	}
-	memcpy(m->buf + m->count, s, len);
-	m->count += len;
+	seq_write(m, s, strlen(s));
 }
 EXPORT_SYMBOL(seq_puts);