Messages in this thread | | | Date | Tue, 19 Jun 2007 12:57:07 -0700 | From | Randy Dunlap <> | Subject | Re: [PATCH 2/2] UML - Add stack usage monitoring |
| |
On Tue, 19 Jun 2007 15:50:03 -0400 Jeff Dike wrote:
> Add a machanism to see how much of a kernel stack is used. This > allocates zeroed stacks and sees where the lowest non-zero byte is on > process exit. It keeps track of the lowest value and logs values as > they get lower. > > Signed-off-by: Jeff Dike <jdike@linux.intel.com> > -- > arch/um/Kconfig.debug | 9 +++++++++ > arch/um/defconfig | 1 + > arch/um/kernel/process.c | 29 +++++++++++++++++++++++++++++ > include/asm-um/thread_info.h | 16 ++++++++++++++++ > 4 files changed, 55 insertions(+) > > Index: linux-2.6.21-mm/arch/um/Kconfig.debug > =================================================================== > --- linux-2.6.21-mm.orig/arch/um/Kconfig.debug 2007-06-19 14:06:36.000000000 -0400 > +++ linux-2.6.21-mm/arch/um/Kconfig.debug 2007-06-19 14:06:44.000000000 -0400 > @@ -47,4 +47,13 @@ config GCOV > If you're involved in UML kernel development and want to use gcov, > say Y. If you're unsure, say N. > > +config DEBUG_STACK_USAGE > + bool "Stack utilization instrumentation" > + default N > + help > + Track the maximum kernel stack usage - this will look at each > + kernel stack at process exit and log it if it's the deepest > + stack seen so far.
Kconfig help text is indented 2 more spaces (by convention or CodingStyle).
> + > + This option will slow down process creation and destruction somewhat. > endmenu > Index: linux-2.6.21-mm/arch/um/kernel/process.c > =================================================================== > --- linux-2.6.21-mm.orig/arch/um/kernel/process.c 2007-06-19 14:06:36.000000000 -0400 > +++ linux-2.6.21-mm/arch/um/kernel/process.c 2007-06-19 15:48:20.000000000 -0400 > @@ -411,3 +411,32 @@ unsigned long arch_align_stack(unsigned > return sp & ~0xf; > } > #endif > + > +#ifdef CONFIG_DEBUG_STACK_USAGE > + > +static DEFINE_SPINLOCK(low_water_lock); > +static int lowest_to_date = THREAD_SIZE; > + > +void check_stack_usage(struct thread_info *s) > +{ > + unsigned int *stack, *p, *end; > + int left; > + > + stack = (unsigned int *) (s + 1); > + end = (unsigned int *) ((unsigned long) s + THREAD_SIZE); > + for (p = stack; p < end; p++) { > + if(*p != 0)
if (*p != NULL) or if (*p)
> + break; > + } > + > + left = (p - stack) * sizeof(*p); > + > + spin_lock(&low_water_lock); > + if (left < lowest_to_date) { > + printk("Greatest stack depth - %d bytes left\n", left);
Does UML need/use KERN_* facility levels in printk() calls?
> + lowest_to_date = left; > + } > + spin_unlock(&low_water_lock); > +} > + > +#endif
--- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code *** - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |