Re: [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return functions

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From	Peter Zijlstra <peterz@infradead.org>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return functions
Date	Sat, 02 Sep 2017 00:10:01 +0200
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On Fri, Sep 01, 2017 at 11:50:03PM +0200, Peter Zijlstra wrote:
> > Did you read the other other part of the description?
> > 
> > 	Further, both functions can be used to accurately trace the refcount
> > 	(refcount_inc() followed by refcount_read() can't be considered
> > 	accurate).
> 
> I must admit to having overlooked that. But can we treat the two issues
> separately? They are quite distinct.

So for tracing purposes inc_return/dec_return don't cover the full set.

In particular: inc_not_zero, dec_not_one and dec_and_*lock are not
covered.

dec_if_one I suppose we only care about the success case, in which case
we knew it was one by inference.

Thread

[RFC PATCH 02/11] refcount: Implement inc/decrement-and-return  functions David Howells <dhowells@redhat.com> - 2017-09-01 17:50 +0200
  Re: [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return  functions Peter Zijlstra <peterz@infradead.org> - 2017-09-01 18:50 +0200
    Re: [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return functions David Howells <dhowells@redhat.com> - 2017-09-01 23:20 +0200
      Re: [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return  functions Peter Zijlstra <peterz@infradead.org> - 2017-09-02 00:00 +0200
        Re: [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return  functions Peter Zijlstra <peterz@infradead.org> - 2017-09-02 00:10 +0200
        Re: [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return functions David Howells <dhowells@redhat.com> - 2017-09-02 01:00 +0200
          Re: [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return  functions Peter Zijlstra <peterz@infradead.org> - 2017-09-04 09:40 +0200
  Re: [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return  functions Christoph Hellwig <hch@infradead.org> - 2017-09-04 17:40 +0200
    Re: [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return functions David Howells <dhowells@redhat.com> - 2017-09-04 18:10 +0200
      Re: [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return  functions Christoph Hellwig <hch@infradead.org> - 2017-09-05 08:50 +0200

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