From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Stephen C. Tweedie" MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <14200.46136.840759.709221@dukat.scot.redhat.com> Date: Tue, 29 Jun 1999 12:55:36 +0100 (BST) Subject: Re: filecache/swapcache questions [RFC] [RFT] [PATCH] kanoj-mm12-2.3.8 Fix swapoff races In-Reply-To: References: ReSent-To: linux-mm@kvack.org ReSent-Message-ID: Sender: owner-linux-mm@kvack.org Return-Path: To: Andrea Arcangeli Cc: Chuck Lever , "Stephen C. Tweedie" , Kanoj Sarcar , torvalds@transmeta.com, linux-mm@kvack.org List-ID: Hi, On Tue, 29 Jun 1999 00:48:18 +0200 (CEST), Andrea Arcangeli said: > I thought a bit about that as well. I also coded a maybe possible > solution. Look at this snapshot: Much better: the synchronisation between the page fault and the swapper is per-page, not per-mm, this way. That way the swapper can afford just to skip the one locked page rather than block for an mm lock. My only reservation is that it's a bit ugly to overload the "locked" bit this way, but it's the only obvious test in try_to_swap_out that we can use. Adding a new PG_Locked_PTE flag for the page, to indicate that somebody is relying on this pte for COW operation and kswapd should skip it, would be an alternative: it makes the intent much more clear (and keeps PG_Locked purely for IO locking, which is really as it should be). --Stephen -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://humbolt.geo.uu.nl/Linux-MM/