Date: Fri, 13 Jan 2006 15:16:05 +0530 From: "Kamal R. Prasad" <kamalp@acm.org> To: prime <guomingyan@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: How priority propagation works on read/write lock? Message-ID: <ac7deb50601130146y4abd573dn2ac47622374c1551@mail.gmail.com> In-Reply-To: <1fa17f810601122232l25551bc5n4e4a01ff6b7921e@mail.gmail.com> References: <1fa17f810601122232l25551bc5n4e4a01ff6b7921e@mail.gmail.com>
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Priority need not be propagated to readers as they will not block other readers. Most likely, you only need to propagate to the writer to avoid priority inversron. regards -kamal On 1/13/06, prime <guomingyan@gmail.com> wrote: > > Hi hackers, > I have a question about how priority propagation works on > read/write lock.On locks that have only one owner at a determinate > moment,we can simply propagate the priority to the owner of lock,but > read/write lock may have many owners at some time,so how can we know > who are the owners? > I browse the OpenSolaris' read/write lock implementation,and find > that, it simply treats the owner of the lock as NULL when readers own > the read/write lock.In this way,we can not propagate our priority to > all threads that block us. > > Thanks very much. > -- > Three passions, simple but overwhelmingly strong, have governed my life: > the longing for love, the search for knowledge, and unbearable pity for > the suffering of mankind. > ---------Bertrand Russell > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org= " >
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