From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx169.postini.com [74.125.245.169]) by kanga.kvack.org (Postfix) with SMTP id 71BD76B00BE for ; Tue, 17 Jan 2012 09:38:35 -0500 (EST) Received: from compute2.internal (compute2.nyi.mail.srv.osa [10.202.2.42]) by gateway1.nyi.mail.srv.osa (Postfix) with ESMTP id 7299B20E53 for ; Tue, 17 Jan 2012 09:38:34 -0500 (EST) Subject: Re: [RFC 0/3] low memory notify From: Colin Walters Date: Tue, 17 Jan 2012 09:38:10 -0500 In-Reply-To: <1326788038-29141-1-git-send-email-minchan@kernel.org> References: <1326788038-29141-1-git-send-email-minchan@kernel.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Message-ID: <1326811093.3467.41.camel@lenny> Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: linux-mm , LKML , leonid.moiseichuk@nokia.com, kamezawa.hiroyu@jp.fujitsu.com, penberg@kernel.org, Rik van Riel , mel@csn.ul.ie, rientjes@google.com, KOSAKI Motohiro , Johannes Weiner , Marcelo Tosatti , Andrew Morton , Ronen Hod On Tue, 2012-01-17 at 17:13 +0900, Minchan Kim wrote: > As you can see, it's respin of mem_notify core of KOSAKI and Marcelo. > (Of course, KOSAKI's original patchset includes more logics but I didn't > include all things intentionally because I want to start from beginning > again) Recently, there are some requirements of notification of system > memory pressure. How does this relate to the existing cgroups memory notifications? See Documentation/cgroups/memory.txt under "10. OOM Control" > It would be very useful for various cases. > For example, QEMU/JVM/Firefox like big memory hogger can release their memory > when memory pressure happens. I don't know about QEMU, but the key characteristic of the JVM and Firefox is that they use garbage collection. Which also applies to Python, Ruby, Google Go, Haskell, OCaml... So what you really want to be investigating here is integration between a garbage collector and the system VM. Your test program looks nothing like a garbage collector. I'd expect most of the performance tradeoffs to be similar between these runtimes. The Azul people have been doing something like this: http://www.managedruntime.org/ In Firefox' case though it can also drop other caches, e.g.: http://people.gnome.org/~federico/news-2007-09.html#firefox-memory-1 As far as the desktop goes, I want to get notified if we're going to hit swap, not if we're close to exhausting the total of RAM+swap. While swap may make sense for servers that care about throughput mainly, I care a lot about latency. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org