On Wed, 27 Feb 2008, J Duff wrote:
> Why does the typed argument (pointer to arc_buf_hdr_t) fail on the return
> probe?
>
> I wrote the following probes for the buf_hash_insert method:
>
> static arc_buf_hdr_t *
> buf_hash_insert(arc_buf_hdr_t *buf, kmutex_t **lockp);
>
> fbt:zfs:buf_hash_insert:entry
> /args[0]->b_datacnt > 1/
> {
> printf("b_datacnt=%d", args[0]->b_datacnt);
> }
>
> fbt:zfs:buf_hash_insert:return
> /args[0]->b_datacnt > 1/
> {
> }
http://www.solarisinternals.com/wiki/index.php/DTrace_Topics_Cheatsheets_Checklists
For function entry probes, the arguments array will provide access to all
function input arguments. For function return probes, the arguments array
provides the return offset in args[0], and the return value of the
function in args[1].
You don't really want to be using args[0] here do you?
-- Dave
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