From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dax.scot.redhat.com (sct@dax.scot.redhat.com [195.89.149.242]) by kvack.org (8.8.7/8.8.7) with ESMTP id IAA11011 for ; Tue, 26 Jan 1999 08:11:33 -0500 Date: Tue, 26 Jan 1999 13:06:41 GMT Message-Id: <199901261306.NAA16382@dax.scot.redhat.com> From: "Stephen C. Tweedie" MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Subject: Re: MM deadlock [was: Re: arca-vm-8...] In-Reply-To: References: Sender: owner-linux-mm@kvack.org To: Gerard Roudier Cc: Alan Cox , Linus Torvalds , sct@redhat.com, werner@suse.de, andrea@e-mind.com, riel@humbolt.geo.uu.nl, Zlatko.Calusic@CARNet.hr, ebiederm+eric@ccr.net, saw@msu.ru, steve@netplus.net, damonbrent@earthlink.net, reese@isn.net, kalle.andersson@mbox303.swipnet.se, bmccann@indusriver.com, bredelin@ucsd.edu, linux-kernel@vger.rutgers.edu, linux-mm@kvack.org List-ID: Hi, On Mon, 25 Jan 1999 22:59:00 +0100 (MET), Gerard Roudier said: > If you tell me that some system XXX is able to quickly free Mega-Bytes of > physical contiguous memory at any time when it is asked for such a > brain-deaded allocation, then for sure, I will never use system XXX, > because this magic behaviour seems not to be possible without some > paranoid VM policy that may affect badly performances for normal stuff. It is really not hard to reserve a certain amount of memory (up to some fraction, say 25% or 50% of physical memory) for use only by pagable allocations. Most desktop boxes will _not_ require more than 50% of memory for locked kernel pages. Recovering any given range of contiguous pages from that pagable region may be expensive but will _always_ be possible, and given that it will usually be a one-off expense during driver setup, there is no reason why we cannot support it. --Stephen -- To unsubscribe, send a message with 'unsubscribe linux-mm my@address' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://humbolt.geo.uu.nl/Linux-MM/