On Wed, 26 Jan 2000, Stephen C. Tweedie wrote:

On Wed, 26 Jan 2000 11:02:37 -0500 (EST), Chuck Lever [off-list ref]
said:

quoted

however, somehow i'd have to guarantee that all buffers associated with a
page that is to be compressed/encrypted are read/written at once.  

Why?  The swapper already does per-page IO locking, so you are protected
against any conflicts while a page is being written out.

it's not a locking issue. the encryption algorithm is a block cipher on
the whole page. in order to decrypt a page, you need to be sure you have
all the pieces.  you can't read parts of the page and decrypt them.

forgetting about encryption for a moment, you don't think the optimization
is useful in the general case?  it's hardly ever used, if at all; plus it
seems to introduce some bugs.  that code would be a lot cleaner without
all the bother.  the "common case," by far, is to read/write the whole
page.

	- Chuck Lever
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