* [PATCH] vmscan: Remove if statement that will never trigger
@ 2011-07-28 21:05 ` Jesper Juhl
0 siblings, 0 replies; 6+ messages in thread
From: Jesper Juhl @ 2011-07-28 21:05 UTC (permalink / raw)
To: linux-kernel
Cc: linux-mm, Rik van Riel, KOSAKI Motohiro, Minchan Kim, Mel Gorman,
Andrew Morton, kanoj, sct
We have this code in mm/vmscan.c:shrink_slab() :
...
if (total_scan < 0) {
printk(KERN_ERR "shrink_slab: %pF negative objects to "
"delete nr=%ld\n",
shrinker->shrink, total_scan);
total_scan = max_pass;
}
...
but since 'total_scan' is of type 'unsigned long' it will never be
less than zero, so there is no way we'll ever enter the true branch of
this if statement - so let's just remove it.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
---
mm/vmscan.c | 6 ------
1 files changed, 0 insertions(+), 6 deletions(-)
Compile tested only.
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 7ef6912..c07d9b1 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -271,12 +271,6 @@ unsigned long shrink_slab(struct shrink_control *shrink,
delta *= max_pass;
do_div(delta, lru_pages + 1);
total_scan += delta;
- if (total_scan < 0) {
- printk(KERN_ERR "shrink_slab: %pF negative objects to "
- "delete nr=%ld\n",
- shrinker->shrink, total_scan);
- total_scan = max_pass;
- }
/*
* We need to avoid excessive windup on filesystem shrinkers
--
1.7.6
--
Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/
Don't top-post http://www.catb.org/jargon/html/T/top-post.html
Plain text mails only, please.
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH] vmscan: Remove if statement that will never trigger
@ 2011-07-28 21:05 ` Jesper Juhl
0 siblings, 0 replies; 6+ messages in thread
From: Jesper Juhl @ 2011-07-28 21:05 UTC (permalink / raw)
To: linux-kernel
Cc: linux-mm, Rik van Riel, KOSAKI Motohiro, Minchan Kim, Mel Gorman,
Andrew Morton, kanoj, sct
We have this code in mm/vmscan.c:shrink_slab() :
...
if (total_scan < 0) {
printk(KERN_ERR "shrink_slab: %pF negative objects to "
"delete nr=%ld\n",
shrinker->shrink, total_scan);
total_scan = max_pass;
}
...
but since 'total_scan' is of type 'unsigned long' it will never be
less than zero, so there is no way we'll ever enter the true branch of
this if statement - so let's just remove it.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
---
mm/vmscan.c | 6 ------
1 files changed, 0 insertions(+), 6 deletions(-)
Compile tested only.
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 7ef6912..c07d9b1 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -271,12 +271,6 @@ unsigned long shrink_slab(struct shrink_control *shrink,
delta *= max_pass;
do_div(delta, lru_pages + 1);
total_scan += delta;
- if (total_scan < 0) {
- printk(KERN_ERR "shrink_slab: %pF negative objects to "
- "delete nr=%ld\n",
- shrinker->shrink, total_scan);
- total_scan = max_pass;
- }
/*
* We need to avoid excessive windup on filesystem shrinkers
--
1.7.6
--
Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/
Don't top-post http://www.catb.org/jargon/html/T/top-post.html
Plain text mails only, please.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] vmscan: Remove if statement that will never trigger
2011-07-28 21:05 ` Jesper Juhl
@ 2011-07-29 6:27 ` KOSAKI Motohiro
-1 siblings, 0 replies; 6+ messages in thread
From: KOSAKI Motohiro @ 2011-07-29 6:27 UTC (permalink / raw)
To: jj; +Cc: linux-kernel, linux-mm, riel, minchan.kim, mgorman, akpm, kanoj, sct
(2011/07/29 6:05), Jesper Juhl wrote:
> We have this code in mm/vmscan.c:shrink_slab() :
> ...
> if (total_scan < 0) {
> printk(KERN_ERR "shrink_slab: %pF negative objects to "
> "delete nr=%ld\n",
> shrinker->shrink, total_scan);
> total_scan = max_pass;
> }
> ...
> but since 'total_scan' is of type 'unsigned long' it will never be
> less than zero, so there is no way we'll ever enter the true branch of
> this if statement - so let's just remove it.
>
> Signed-off-by: Jesper Juhl <jj@chaosbits.net>
> ---
> mm/vmscan.c | 6 ------
> 1 files changed, 0 insertions(+), 6 deletions(-)
>
> Compile tested only.
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 7ef6912..c07d9b1 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -271,12 +271,6 @@ unsigned long shrink_slab(struct shrink_control *shrink,
> delta *= max_pass;
> do_div(delta, lru_pages + 1);
> total_scan += delta;
> - if (total_scan < 0) {
> - printk(KERN_ERR "shrink_slab: %pF negative objects to "
> - "delete nr=%ld\n",
> - shrinker->shrink, total_scan);
> - total_scan = max_pass;
> - }
>
> /*
> * We need to avoid excessive windup on filesystem shrinkers
Good catch.
However this seems intended to catch a overflow. So, I'd suggest to make proper
overflow check instead.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] vmscan: Remove if statement that will never trigger
@ 2011-07-29 6:27 ` KOSAKI Motohiro
0 siblings, 0 replies; 6+ messages in thread
From: KOSAKI Motohiro @ 2011-07-29 6:27 UTC (permalink / raw)
To: jj; +Cc: linux-kernel, linux-mm, riel, minchan.kim, mgorman, akpm, kanoj, sct
(2011/07/29 6:05), Jesper Juhl wrote:
> We have this code in mm/vmscan.c:shrink_slab() :
> ...
> if (total_scan < 0) {
> printk(KERN_ERR "shrink_slab: %pF negative objects to "
> "delete nr=%ld\n",
> shrinker->shrink, total_scan);
> total_scan = max_pass;
> }
> ...
> but since 'total_scan' is of type 'unsigned long' it will never be
> less than zero, so there is no way we'll ever enter the true branch of
> this if statement - so let's just remove it.
>
> Signed-off-by: Jesper Juhl <jj@chaosbits.net>
> ---
> mm/vmscan.c | 6 ------
> 1 files changed, 0 insertions(+), 6 deletions(-)
>
> Compile tested only.
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 7ef6912..c07d9b1 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -271,12 +271,6 @@ unsigned long shrink_slab(struct shrink_control *shrink,
> delta *= max_pass;
> do_div(delta, lru_pages + 1);
> total_scan += delta;
> - if (total_scan < 0) {
> - printk(KERN_ERR "shrink_slab: %pF negative objects to "
> - "delete nr=%ld\n",
> - shrinker->shrink, total_scan);
> - total_scan = max_pass;
> - }
>
> /*
> * We need to avoid excessive windup on filesystem shrinkers
Good catch.
However this seems intended to catch a overflow. So, I'd suggest to make proper
overflow check instead.
--
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] vmscan: Remove if statement that will never trigger
2011-07-29 6:27 ` KOSAKI Motohiro
@ 2011-07-29 9:16 ` Jesper Juhl
-1 siblings, 0 replies; 6+ messages in thread
From: Jesper Juhl @ 2011-07-29 9:16 UTC (permalink / raw)
To: KOSAKI Motohiro
Cc: linux-kernel, linux-mm, riel, minchan.kim, mgorman, akpm, kanoj, sct
On Fri, 29 Jul 2011, KOSAKI Motohiro wrote:
> (2011/07/29 6:05), Jesper Juhl wrote:
> > We have this code in mm/vmscan.c:shrink_slab() :
> > ...
> > if (total_scan < 0) {
> > printk(KERN_ERR "shrink_slab: %pF negative objects to "
> > "delete nr=%ld\n",
> > shrinker->shrink, total_scan);
> > total_scan = max_pass;
> > }
> > ...
> > but since 'total_scan' is of type 'unsigned long' it will never be
> > less than zero, so there is no way we'll ever enter the true branch of
> > this if statement - so let's just remove it.
> >
> > Signed-off-by: Jesper Juhl <jj@chaosbits.net>
> > ---
> > mm/vmscan.c | 6 ------
> > 1 files changed, 0 insertions(+), 6 deletions(-)
> >
> > Compile tested only.
> >
> > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > index 7ef6912..c07d9b1 100644
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -271,12 +271,6 @@ unsigned long shrink_slab(struct shrink_control *shrink,
> > delta *= max_pass;
> > do_div(delta, lru_pages + 1);
> > total_scan += delta;
> > - if (total_scan < 0) {
> > - printk(KERN_ERR "shrink_slab: %pF negative objects to "
> > - "delete nr=%ld\n",
> > - shrinker->shrink, total_scan);
> > - total_scan = max_pass;
> > - }
> >
> > /*
> > * We need to avoid excessive windup on filesystem shrinkers
>
> Good catch.
>
> However this seems intended to catch a overflow. So, I'd suggest to make proper
> overflow check instead.
>
Right. We probably shouldn't just remove it.
I'll cook a new version of the patch tonight that properly checks for
overflow.
--
Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/
Don't top-post http://www.catb.org/jargon/html/T/top-post.html
Plain text mails only, please.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] vmscan: Remove if statement that will never trigger
@ 2011-07-29 9:16 ` Jesper Juhl
0 siblings, 0 replies; 6+ messages in thread
From: Jesper Juhl @ 2011-07-29 9:16 UTC (permalink / raw)
To: KOSAKI Motohiro
Cc: linux-kernel, linux-mm, riel, minchan.kim, mgorman, akpm, kanoj, sct
On Fri, 29 Jul 2011, KOSAKI Motohiro wrote:
> (2011/07/29 6:05), Jesper Juhl wrote:
> > We have this code in mm/vmscan.c:shrink_slab() :
> > ...
> > if (total_scan < 0) {
> > printk(KERN_ERR "shrink_slab: %pF negative objects to "
> > "delete nr=%ld\n",
> > shrinker->shrink, total_scan);
> > total_scan = max_pass;
> > }
> > ...
> > but since 'total_scan' is of type 'unsigned long' it will never be
> > less than zero, so there is no way we'll ever enter the true branch of
> > this if statement - so let's just remove it.
> >
> > Signed-off-by: Jesper Juhl <jj@chaosbits.net>
> > ---
> > mm/vmscan.c | 6 ------
> > 1 files changed, 0 insertions(+), 6 deletions(-)
> >
> > Compile tested only.
> >
> > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > index 7ef6912..c07d9b1 100644
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -271,12 +271,6 @@ unsigned long shrink_slab(struct shrink_control *shrink,
> > delta *= max_pass;
> > do_div(delta, lru_pages + 1);
> > total_scan += delta;
> > - if (total_scan < 0) {
> > - printk(KERN_ERR "shrink_slab: %pF negative objects to "
> > - "delete nr=%ld\n",
> > - shrinker->shrink, total_scan);
> > - total_scan = max_pass;
> > - }
> >
> > /*
> > * We need to avoid excessive windup on filesystem shrinkers
>
> Good catch.
>
> However this seems intended to catch a overflow. So, I'd suggest to make proper
> overflow check instead.
>
Right. We probably shouldn't just remove it.
I'll cook a new version of the patch tonight that properly checks for
overflow.
--
Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/
Don't top-post http://www.catb.org/jargon/html/T/top-post.html
Plain text mails only, please.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2011-07-29 9:16 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2011-07-28 21:05 [PATCH] vmscan: Remove if statement that will never trigger Jesper Juhl
2011-07-28 21:05 ` Jesper Juhl
2011-07-29 6:27 ` KOSAKI Motohiro
2011-07-29 6:27 ` KOSAKI Motohiro
2011-07-29 9:16 ` Jesper Juhl
2011-07-29 9:16 ` Jesper Juhl
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