| From | Nick Piggin <> | Subject | Re: [PATCH 23/43] CacheFiles: Permit the page lock state to be monitored [ver #46] | Date | Fri, 3 Apr 2009 02:37:25 +1100 |
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On Thursday 02 April 2009 10:05:20 David Howells wrote: > Add a function to install a monitor on the page lock waitqueue for a particular > page, thus allowing the page being unlocked to be detected. > > This is used by CacheFiles to detect read completion on a page in the backing > filesystem so that it can then copy the data to the waiting netfs page.
I prefer to nack this because it is exporting details of the page locking mechanism. unlock_page is very heavyweight in large part because of the memory barriers and cacheline required to check the waitqueue. I have patches to avoid all that if the page lock is not contended.
What's wrong with using wait_on_page_locked, like everyone else does?
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