Re: bug leading to stuck pages

Mark Hemment (markhe@sco.COM)
Thu, 5 Jun 1997 14:26:27 +0100 (BST)

On Wed, 4 Jun 1997, Bill Hawes wrote:
> There are other problems as well -- if it's possible for two tasks to
> post async reads to the same page, then it would be very tricky to
> restore the PG_locked flag. Also, using PG_free_after would be a
> problem, since only one decrement of the page->count would happen.

It is not possible.
The page-cache in mm/filemap.c ensures only one read-per-page.
(and get_hash_table() in brw_page() checks that they are not buffers
containing the required data, or pending on the same block(s)).

Regards,

markhe

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Mark Hemment UNIX/C Sotware Engineer (contractor)
"Success has many fathers. Failure is a b**tard"
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