From: Dave Chinner <david@fromorbit.com>
To: Scott Wood <scottwood@freescale.com>
Cc: trivial@kernel.org, linux-kernel@vger.kernel.org, xfs@oss.sgi.com
Subject: Re: [PATCH 21/22] xfs: %pF is only for function pointers
Date: Mon, 31 Aug 2015 18:06:57 +1000 [thread overview]
Message-ID: <20150831080657.GF26895@dastard> (raw)
In-Reply-To: <1426130037-17956-21-git-send-email-scottwood@freescale.com>
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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next prev parent reply other threads:[~2015-08-31 8:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1426130037-17956-1-git-send-email-scottwood@freescale.com>
2015-03-12 3:13 ` [PATCH 21/22] xfs: %pF is only for function pointers Scott Wood
2015-08-31 8:06 ` Dave Chinner [this message]
[not found] ` <1441049065.4966.38.camel@freescale.com>
2015-08-31 19:45 ` Steven Rostedt
[not found] ` <1441051104.4966.41.camel@freescale.com>
2015-08-31 20:05 ` Steven Rostedt
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