Messages in this thread |  | | | From | David Howells <> | | Subject | Re: rwsem: down_read_unfair() proposal | | Date | Wed, 05 May 2010 11:06:44 +0100 |
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Michel Lespinasse <walken@google.com> wrote:
> and looks like it's doable with the x86 rwsem implementation as well in a > way that would only involve changes to the rwsem spinlock-protected slow > paths in lib/rwsem.c .
It's not as easy as it seems. Once an XADD-based rwsem is contended, you cannot necessarily tell without looking at the queue whether the rwsem is currently write-locked or read-locked.
David
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