From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from cs.utexas.edu (root@cs.utexas.edu [128.83.139.9]) by kvack.org (8.8.7/8.8.7) with ESMTP id WAA26540 for ; Sun, 10 Jan 1999 22:39:04 -0500 Received: from feta.cs.utexas.edu (wilson@feta.cs.utexas.edu [128.83.120.125]) by cs.utexas.edu (8.8.5/8.8.5) with ESMTP id VAA18685 for ; Sun, 10 Jan 1999 21:38:47 -0600 (CST) Message-Id: <199901110338.VAA19737@feta.cs.utexas.edu> From: "Paul R. Wilson" Date: Sun, 10 Jan 1999 21:38:46 -0600 Subject: question about try_to_swap_out() Sender: owner-linux-mm@kvack.org To: linux-mm@kvack.org List-ID: After checking that that a page is present and pageable, try_to_swap_out() checks to see if the page is reserved or locked or not DMA'able when where looking for a DMA page. If any of these three things is true, it returns 0 without changing anything. It seems to me that it should go ahead and check the pte age bit, and update the page frame's PG_referenced bit, before returning 0. One case I'm concerned about is a non-DMA page whose reference bit doesn't get reset as usual. This page will still look recently-touched at the next clock sweep, and that will make it stay cached longer, just because we were looking for a DMA'able page when the clock hand reached it this time. I'm unclear what the significance is for a locked page. Am I off-base here, or should the conditional that checks to see whether a page is young (and updates the reference bits) be moved up ahead of the conditional that checks to see whether a page is (reserved | locked | not-dma-but-we-need-dma)? Apologies if I'm way off base here. -- This is a majordomo managed list. To unsubscribe, send a message with the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org