Re: libpager multi-client support

[Kalle Olavi Niemitalo]

"Brent W. Baccala" <cosine@freesoft.org> writes:

> Second, I can't find anywhere in the hurd source tree where this function
> is actually used.

Commit 84cf9c0f312637b670cc87224ff7e7c4da659e36 on 2013-09-17
removed the ufs directory, in which the offer_data function used
to call pager_offer_page.  The last argument of pager_offer_page
always pointed to a page that was part of the global zeroblock,
which was the size of a filesystem block and filled with zeroes.

> Third, why would we want this feature?  Why would a memory server ever want
> to send an unsolicited page to a client?

One of the offer_data calls was preceded by a comment:

  /* Make sure that any pages of this block which just became allocated
     don't get paged in from disk. */

I don't know how ext2fs makes sure of that, or whether
pager_offer_page might again be needed for the same purpose in
the future.