From: Al Viro <viro@ZenIV.linux.org.uk>
To: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>,
Dan Williams <dan.j.williams@intel.com>,
Dave Chinner <david@fromorbit.com>,
Ingo Molnar <mingo@redhat.com>, Jan Kara <jack@suse.cz>,
Matthew Wilcox <mawilcox@microsoft.com>,
Steven Rostedt <rostedt@goodmis.org>,
linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-nvdimm@ml01.01.org
Subject: Re: [PATCH 3/6] dax: add tracepoint infrastructure, PMD tracing
Date: Thu, 24 Nov 2016 17:32:20 +0000 [thread overview]
Message-ID: <20161124173220.GR1555@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1479926662-21718-4-git-send-email-ross.zwisler@linux.intel.com>
On Wed, Nov 23, 2016 at 11:44:19AM -0700, Ross Zwisler wrote:
> Tracepoints are the standard way to capture debugging and tracing
> information in many parts of the kernel, including the XFS and ext4
> filesystems. Create a tracepoint header for FS DAX and add the first DAX
> tracepoints to the PMD fault handler. This allows the tracing for DAX to
> be done in the same way as the filesystem tracing so that developers can
> look at them together and get a coherent idea of what the system is doing.
It also has one hell of potential for becoming a massive nuisance.
Keep in mind that if any userland code becomes dependent on those - that's it,
they have become parts of stable userland ABI and are to be maintained
indefinitely. Don't expect "tracepoints are special case" to prevent that.
So treat anything you add in that manner as potential stable ABI
you might have to keep around forever. It's *not* a glorified debugging
printk.
next prev parent reply other threads:[~2016-11-24 17:32 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-23 18:44 [PATCH 0/6] introduce DAX tracepoint support Ross Zwisler
2016-11-23 18:44 ` [PATCH 1/6] dax: fix build breakage with ext4, dax and !iomap Ross Zwisler
2016-11-24 9:02 ` Jan Kara
2016-11-28 19:15 ` Ross Zwisler
2016-11-29 8:53 ` Jan Kara
2016-11-30 19:04 ` Ross Zwisler
2016-12-01 7:53 ` Jan Kara
2016-11-23 18:44 ` [PATCH 2/6] dax: remove leading space from labels Ross Zwisler
2016-11-24 9:11 ` Jan Kara
2016-11-24 19:42 ` Dan Williams
2016-11-28 19:20 ` Ross Zwisler
2016-11-23 18:44 ` [PATCH 3/6] dax: add tracepoint infrastructure, PMD tracing Ross Zwisler
2016-11-24 9:16 ` Jan Kara
2016-11-24 17:32 ` Al Viro [this message]
2016-11-25 2:49 ` Dave Chinner
2016-11-25 4:14 ` Al Viro
2016-11-25 7:06 ` Dave Chinner
2016-11-25 7:37 ` Al Viro
2016-11-25 19:51 ` Linus Torvalds
2016-11-25 20:36 ` Mike Marshall
2016-11-25 21:48 ` Theodore Ts'o
2016-11-25 23:38 ` Linus Torvalds
2016-11-28 8:33 ` Jan Kara
2016-11-27 22:42 ` Dave Chinner
2016-11-28 0:58 ` Linus Torvalds
2016-11-28 1:45 ` Al Viro
2016-11-28 9:09 ` Dave Chinner
2016-11-25 3:00 ` Dave Chinner
2016-11-28 22:46 ` Ross Zwisler
2016-11-29 2:02 ` Dave Chinner
2017-03-08 22:05 ` Mike Marshall
2016-11-23 18:44 ` [PATCH 4/6] dax: update MAINTAINERS entries for FS DAX Ross Zwisler
2016-11-23 18:44 ` [PATCH 5/6] dax: add tracepoints to dax_pmd_load_hole() Ross Zwisler
2016-11-24 9:20 ` Jan Kara
2016-11-23 18:44 ` [PATCH 6/6] dax: add tracepoints to dax_pmd_insert_mapping() Ross Zwisler
2016-11-24 9:22 ` Jan Kara
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