From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by ug-out-1314.google.com with SMTP id o2so848299uge for ; Wed, 26 Jul 2006 06:04:06 -0700 (PDT) Message-ID: <6e0cfd1d0607260604w3e8636e4taaea4bc918397b34@mail.gmail.com> Date: Wed, 26 Jul 2006 15:04:05 +0200 From: "Martin Schwidefsky" Subject: Re: [PATCH] mm: inactive-clean list In-Reply-To: <1153912268.2732.30.camel@taijtu> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <1153167857.31891.78.camel@lappy> <44C30E33.2090402@redhat.com> <6e0cfd1d0607260400r731489a1tfd9e6c5a197fb0bd@mail.gmail.com> <1153912268.2732.30.camel@taijtu> Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: Rik van Riel , linux-mm , Linus Torvalds , Andrew Morton , linux-kernel List-ID: On 7/26/06, Peter Zijlstra wrote: > > Hmm, I wonder how the inactive clean list helps in regard to the fast > > host reclaim > > scheme. In particular since the memory pressure that triggers the > > reclaim is in the > > host, not in the guest. So all pages might be on the active list but > > the host still > > wants to be able to discard pages. > > > > I think Rik would want to set all the already unmapped pages to volatile > state in the hypervisor. > > These pages can be dropped without loss of information on the guest > system since they are all already on a backing-store, be it regular > files or swap. I guessed that as well. It isn't good enough. Consider a guest with a large (virtual) memory size and a host with a small physical memory size. The guest will never put any page on the inactive_clean list because it does not have memory pressure. vmscan will never run. The host wants to reclaim memory of the guest, but since the inactive_clean list is empty it will find only stable pages. -- blue skies, Martin -- 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