Re: [patch] vmscan: print shrink_slab symbol name on negative shrinkerobjects

From: David Rientjes
Date: Fri Mar 20 2009 - 06:16:47 EST


On Thu, 19 Mar 2009, Andrew Morton wrote:

> > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -40,6 +40,7 @@
> > #include <linux/memcontrol.h>
> > #include <linux/delayacct.h>
> > #include <linux/sysctl.h>
> > +#include <linux/kallsyms.h>
> >
> > #include <asm/tlbflush.h>
> > #include <asm/div64.h>
> > @@ -214,8 +215,12 @@ unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
> > do_div(delta, lru_pages + 1);
> > shrinker->nr += delta;
> > if (shrinker->nr < 0) {
> > - printk(KERN_ERR "%s: nr=%ld\n",
> > - __func__, shrinker->nr);
> > + char symname[KSYM_NAME_LEN];
> > +
> > + if (lookup_symbol_name((unsigned long)shrinker->shrink,
> > + symname) > 0)
> > + printk(KERN_ERR "shrink_slab: %s nr=%ld\n",
> > + symname, shrinker->nr);
> > shrinker->nr = max_pass;
> > }
>
> Can we use the new printk("%pF", ...) here?
>

Cool, that's super convenient.


vmscan: print shrink_slab symbol name on negative shrinker objects

When a shrinker has a negative number of objects to delete, the symbol
name of the shrinker should be printed, not shrink_slab. This also makes
the error message slightly more informative.

Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
mm/vmscan.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -214,8 +214,9 @@ unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
do_div(delta, lru_pages + 1);
shrinker->nr += delta;
if (shrinker->nr < 0) {
- printk(KERN_ERR "%s: nr=%ld\n",
- __func__, shrinker->nr);
+ printk(KERN_ERR "shrink_slab: %pF negative objects to "
+ "delete nr=%ld\n",
+ shrinker->shrink, shrinker->nr);
shrinker->nr = max_pass;
}

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