From mboxrd@z Thu Jan 1 00:00:00 1970 Content-class: urn:content-classes:message Subject: RE: [patch] vmsig: notify user applications of virtual memory events via real-time signals MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 8BIT Date: Tue, 22 Nov 2005 16:53:22 -0500 Message-ID: From: "Emery Berger" Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel , Yi Feng Cc: linux-mm@kvack.org, Andrew Morton , Matthew Hertz List-ID: > That seems pretty high overhead. I wonder if it wouldn't work > similarly well for the kernel to simply notify the registrered > apps that memory is running low and they should garbage collect > _something_, without caring which pages. Actually, it's quite important that the application know exactly which page is being evicted, in order that it be "bookmarked". We found that this particular aspect of the garbage collection algorithm was crucial (it's in the paper). Best, -- emery -- Emery Berger Assistant Professor Dept. of Computer Science University of Massachusetts, Amherst www.cs.umass.edu/~emery > -----Original Message----- > From: Rik van Riel [mailto:riel@redhat.com] > Sent: Tuesday, November 22, 2005 4:45 PM > To: Yi Feng > Cc: linux-mm@kvack.org; 'Andrew Morton'; Emery Berger; 'Matthew Hertz' > Subject: Re: [patch] vmsig: notify user applications of virtual memory > events via real-time signals > > On Tue, 22 Nov 2005, Yi Feng wrote: > > > The user application can therefore maintain the residence information of > > all its pages and cooperate with the kernel under memory pressure. > > That seems pretty high overhead. I wonder if it wouldn't work > similarly well for the kernel to simply notify the registrered > apps that memory is running low and they should garbage collect > _something_, without caring which pages. > > Then the apps can "shoot holes" in their memory use by calling > madvise with MADV_DONTNEED on the pages the application judges > to be the least likely ones to be used again. > > OTOH, maybe keeping state for each page is low enough overhead. > I will have to read your patch to figure out the details ;) > > -- > All Rights Reversed -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org