From: Linus Torvalds <torvalds@linux-foundation.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <mawilcox@microsoft.com>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Christoph Hellwig <hch@lst.de>, linux-mm <linux-mm@kvack.org>,
Ingo Molnar <mingo@redhat.com>, Al Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH 3/6] dax: add tracepoint infrastructure, PMD tracing
Date: Sun, 27 Nov 2016 16:58:43 -0800 [thread overview]
Message-ID: <CA+55aFwmCVZECoMszXZkJ8tSpG5+Ynt-5EKxKqDepNtjUv5vkg@mail.gmail.com> (raw)
In-Reply-To: <20161127224208.GA31101@dastard>
On Sun, Nov 27, 2016 at 2:42 PM, Dave Chinner <david@fromorbit.com> wrote:
>
> And that's exactly why we need a method of marking tracepoints as
> stable. How else are we going to know whether a specific tracepoint
> is stable if the kernel code doesn't document that it's stable?
You are living in some unrealistic dream-world where you think you can
get the right tracepoint on the first try.
So there is no way in hell I would ever mark any tracepoint "stable"
until it has had a fair amount of use, and there are useful tools that
actually make use of it, and it has shown itself to be the right
trace-point.
And once that actually happens, what's the advantage of marking it
stable? None. It's a catch-22. Before it has uses and has been tested
and found to be good, it's not stable. And after, it's pointless.
So at no point does such a "stable" tracepoint marking make sense. At
most, you end up adding a comment saying "this tracepoint is used by
tools such-and-such".
Linus
_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm
WARNING: multiple messages have this Message-ID (diff)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>,
Dan Williams <dan.j.williams@intel.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-ext4@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>
Subject: Re: [PATCH 3/6] dax: add tracepoint infrastructure, PMD tracing
Date: Sun, 27 Nov 2016 16:58:43 -0800 [thread overview]
Message-ID: <CA+55aFwmCVZECoMszXZkJ8tSpG5+Ynt-5EKxKqDepNtjUv5vkg@mail.gmail.com> (raw)
In-Reply-To: <20161127224208.GA31101@dastard>
On Sun, Nov 27, 2016 at 2:42 PM, Dave Chinner <david@fromorbit.com> wrote:
>
> And that's exactly why we need a method of marking tracepoints as
> stable. How else are we going to know whether a specific tracepoint
> is stable if the kernel code doesn't document that it's stable?
You are living in some unrealistic dream-world where you think you can
get the right tracepoint on the first try.
So there is no way in hell I would ever mark any tracepoint "stable"
until it has had a fair amount of use, and there are useful tools that
actually make use of it, and it has shown itself to be the right
trace-point.
And once that actually happens, what's the advantage of marking it
stable? None. It's a catch-22. Before it has uses and has been tested
and found to be good, it's not stable. And after, it's pointless.
So at no point does such a "stable" tracepoint marking make sense. At
most, you end up adding a comment saying "this tracepoint is used by
tools such-and-such".
Linus
WARNING: multiple messages have this Message-ID (diff)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>,
Dan Williams <dan.j.williams@intel.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-ext4@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>
Subject: Re: [PATCH 3/6] dax: add tracepoint infrastructure, PMD tracing
Date: Sun, 27 Nov 2016 16:58:43 -0800 [thread overview]
Message-ID: <CA+55aFwmCVZECoMszXZkJ8tSpG5+Ynt-5EKxKqDepNtjUv5vkg@mail.gmail.com> (raw)
In-Reply-To: <20161127224208.GA31101@dastard>
On Sun, Nov 27, 2016 at 2:42 PM, Dave Chinner <david@fromorbit.com> wrote:
>
> And that's exactly why we need a method of marking tracepoints as
> stable. How else are we going to know whether a specific tracepoint
> is stable if the kernel code doesn't document that it's stable?
You are living in some unrealistic dream-world where you think you can
get the right tracepoint on the first try.
So there is no way in hell I would ever mark any tracepoint "stable"
until it has had a fair amount of use, and there are useful tools that
actually make use of it, and it has shown itself to be the right
trace-point.
And once that actually happens, what's the advantage of marking it
stable? None. It's a catch-22. Before it has uses and has been tested
and found to be good, it's not stable. And after, it's pointless.
So at no point does such a "stable" tracepoint marking make sense. At
most, you end up adding a comment saying "this tracepoint is used by
tools such-and-such".
Linus
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next prev parent reply other threads:[~2016-11-28 0:58 UTC|newest]
Thread overview: 124+ 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 ` Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-23 18:44 ` [PATCH 1/6] dax: fix build breakage with ext4, dax and !iomap Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-24 9:02 ` Jan Kara
2016-11-24 9:02 ` Jan Kara
2016-11-24 9:02 ` Jan Kara
2016-11-24 9:02 ` Jan Kara
2016-11-28 19:15 ` Ross Zwisler
2016-11-28 19:15 ` Ross Zwisler
2016-11-28 19:15 ` Ross Zwisler
2016-11-29 8:53 ` Jan Kara
2016-11-29 8:53 ` Jan Kara
2016-11-29 8:53 ` Jan Kara
2016-11-29 8:53 ` Jan Kara
2016-11-30 19:04 ` Ross Zwisler
2016-11-30 19:04 ` Ross Zwisler
2016-11-30 19:04 ` Ross Zwisler
2016-11-30 19:04 ` Ross Zwisler
2016-12-01 7:53 ` Jan Kara
2016-12-01 7:53 ` Jan Kara
2016-12-01 7:53 ` Jan Kara
2016-12-01 7:53 ` Jan Kara
2016-11-23 18:44 ` [PATCH 2/6] dax: remove leading space from labels Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-24 9:11 ` Jan Kara
2016-11-24 9:11 ` Jan Kara
2016-11-24 9:11 ` Jan Kara
2016-11-24 19:42 ` Dan Williams
2016-11-24 19:42 ` Dan Williams
2016-11-24 19:42 ` Dan Williams
2016-11-28 19:20 ` Ross Zwisler
2016-11-28 19:20 ` Ross Zwisler
2016-11-28 19:20 ` Ross Zwisler
2016-11-23 18:44 ` [PATCH 3/6] dax: add tracepoint infrastructure, PMD tracing Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-24 9:16 ` Jan Kara
2016-11-24 9:16 ` Jan Kara
2016-11-24 9:16 ` Jan Kara
2016-11-24 9:16 ` Jan Kara
2016-11-24 17:32 ` Al Viro
2016-11-24 17:32 ` Al Viro
2016-11-24 17:32 ` Al Viro
2016-11-24 17:32 ` Al Viro
2016-11-25 2:49 ` Dave Chinner
2016-11-25 2:49 ` Dave Chinner
2016-11-25 2:49 ` Dave Chinner
2016-11-25 2:49 ` Dave Chinner
2016-11-25 4:14 ` Al Viro
2016-11-25 4:14 ` Al Viro
2016-11-25 4:14 ` Al Viro
2016-11-25 4:14 ` Al Viro
2016-11-25 7:06 ` Dave Chinner
2016-11-25 7:06 ` Dave Chinner
2016-11-25 7:06 ` Dave Chinner
2016-11-25 7:06 ` Dave Chinner
2016-11-25 7:37 ` Al Viro
2016-11-25 7:37 ` Al Viro
2016-11-25 7:37 ` Al Viro
2016-11-25 7:37 ` Al Viro
2016-11-25 19:51 ` Linus Torvalds
2016-11-25 19:51 ` Linus Torvalds
2016-11-25 19:51 ` Linus Torvalds
2016-11-25 20:36 ` Mike Marshall
2016-11-25 20:36 ` Mike Marshall
2016-11-25 20:36 ` Mike Marshall
2016-11-25 21:48 ` Theodore Ts'o
2016-11-25 21:48 ` Theodore Ts'o
2016-11-25 21:48 ` Theodore Ts'o
2016-11-25 23:38 ` Linus Torvalds
2016-11-25 23:38 ` Linus Torvalds
2016-11-25 23:38 ` Linus Torvalds
2016-11-28 8:33 ` Jan Kara
2016-11-28 8:33 ` Jan Kara
2016-11-28 8:33 ` Jan Kara
2016-11-27 22:42 ` Dave Chinner
2016-11-27 22:42 ` Dave Chinner
2016-11-27 22:42 ` Dave Chinner
2016-11-28 0:58 ` Linus Torvalds [this message]
2016-11-28 0:58 ` Linus Torvalds
2016-11-28 0:58 ` Linus Torvalds
2016-11-28 1:45 ` Al Viro
2016-11-28 1:45 ` Al Viro
2016-11-28 9:09 ` Dave Chinner
2016-11-28 9:09 ` Dave Chinner
2016-11-28 9:09 ` Dave Chinner
2016-11-25 3:00 ` Dave Chinner
2016-11-25 3:00 ` Dave Chinner
2016-11-25 3:00 ` Dave Chinner
2016-11-28 22:46 ` Ross Zwisler
2016-11-28 22:46 ` Ross Zwisler
2016-11-28 22:46 ` Ross Zwisler
2016-11-28 22:46 ` Ross Zwisler
2016-11-29 2:02 ` Dave Chinner
2016-11-29 2:02 ` Dave Chinner
2016-11-29 2:02 ` Dave Chinner
2017-03-08 22:05 ` Mike Marshall
2017-03-08 22:05 ` Mike Marshall
2017-03-08 22:05 ` Mike Marshall
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 ` Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-23 18:44 ` [PATCH 5/6] dax: add tracepoints to dax_pmd_load_hole() Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-24 9:20 ` Jan Kara
2016-11-24 9:20 ` Jan Kara
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
2016-11-23 18:44 ` Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-23 18:44 ` Ross Zwisler
2016-11-24 9:22 ` Jan Kara
2016-11-24 9:22 ` Jan Kara
2016-11-24 9:22 ` Jan Kara
2016-11-24 9:22 ` Jan Kara
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