Messages in this thread | | | Date | Mon, 31 Aug 2015 18:06:57 +1000 | From | Dave Chinner <> | Subject | Re: [PATCH 21/22] xfs: %pF is only for function pointers |
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On Wed, Mar 11, 2015 at 10:13:56PM -0500, Scott Wood wrote: > Use %pS for actual addresses, otherwise you'll get bad output > on arches like ppc64 where %pF expects a function descriptor. > > Signed-off-by: Scott Wood <scottwood@freescale.com> > Cc: xfs@oss.sgi.com
Scott, I've just found that this change (commit 65dd297 "xfs: %pF is only for function pointers") breaks the symbolic printing in XFS trace events on x86_64. eg.
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h > index 51372e3..b5ac81e 100644 > --- a/fs/xfs/xfs_trace.h > +++ b/fs/xfs/xfs_trace.h > @@ -115,7 +115,7 @@ DECLARE_EVENT_CLASS(xfs_perag_class, > __entry->refcount = refcount; > __entry->caller_ip = caller_ip; > ), > - TP_printk("dev %d:%d agno %u refcount %d caller %pf", > + TP_printk("dev %d:%d agno %u refcount %d caller %ps", > MAJOR(__entry->dev), MINOR(__entry->dev), > __entry->agno, > __entry->refcount,
This results in output like this:
760.828474: xfs_perag_get: dev 253:32 agno 13 refcount 10 caller 0xffffffff814eef02s 760.828476: xfs_perag_put: dev 253:32 agno 13 refcount 9 caller 0xffffffff814eefe8s
When I revert this commit, I get:
71.911265: xfs_perag_get: dev 253:32 agno 0 refcount 11 caller xfs_extent_busy_insert 71.911266: xfs_perag_put: dev 253:32 agno 0 refcount 10 caller xfs_extent_busy_insert
Which is exactly what we should be getting from the tracing. I'm using trace-cmd to gather and print the events, and it breaks both old and current versions of trace-cmd.
Can you please look into why this change broke the tracing output on x86-64 - if there is no obvious/easy fix for it, then I'm simply going to revert it because having the tracing work correctly on x86-64 is far more important to us than ppc64 or ia64....
Cheers,
Dave. -- Dave Chinner david@fromorbit.com
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