Re: [PATCH v2] Tracepoint Tapset for Memory Subsystem

[Josh Stone <jistone@redhat.com>]

On 09/24/2009 11:08 AM, Rajasekhar Duddu wrote:
> 
> Hi, I have modified the patch according to the comments passed
> by Frank and David.
> 
> Many thanks to Frank And David.
> 
> Changelog:
> 	Removed the Hardcoded constants in converting GFPFLAGS.
> 	Added a kprobe based fallback probe to kfree.

Why is kfree the only one you're adding with a kprobe fallback?  This is
a good feature to have!

> +/**
> + * probe kmem.kfree - Fires when <command>kfree</comand> is requested.
> + * @call_site: Address of the function calling this kmemory function.
> + * @ptr: Pointer to the kmemory allocated which is returned by kmalloc
> + */
> +probe kmem.kfree.kp = kernel.function("kfree") {
> +	name = "kfree"
> +	call_site = symname(call_site())
> +	ptr = $x
> +}
> +
> +probe kmem.kfree.tp = kernel.trace("kfree") {
> +	name = "kfree"
> +	call_site = symname($call_site)
> +	ptr = $ptr
> +}
> +
> +probe kmem.kfree = kmem.kfree.tp !,
> +		   kmem.kfree.kp
> +{}

Please use an underscored prefix (e.g. __kmem) for internal details that
the user isn't meant to use directly, like the .tp/.kp branches.

I'd also like to see a consistent prefix in this tapset.  The existing
probe points in memory.stp are all vm.*, so it's probably best to stick
with that.

Thanks,

Josh