From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 15 Feb 2007 20:24:25 -0800 From: Andrew Morton Subject: Re: [RFC] Remove unswappable anonymous pages off the LRU Message-Id: <20070215202425.bd9d028e.akpm@linux-foundation.org> In-Reply-To: <45D52F89.5020008@redhat.com> References: <20070215171355.67c7e8b4.akpm@linux-foundation.org> <45D50B79.5080002@mbligh.org> <20070215174957.f1fb8711.akpm@linux-foundation.org> <20070215184800.e2820947.akpm@linux-foundation.org> <20070215191858.1a864874.akpm@linux-foundation.org> <20070215194258.a354f428.akpm@linux-foundation.org> <45D52F89.5020008@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: Christoph Lameter , Martin Bligh , linux-mm@kvack.org, Nick Piggin , Peter Zijlstra , KAMEZAWA Hiroyuki List-ID: On Thu, 15 Feb 2007 23:14:01 -0500 Rik van Riel wrote: > Christoph Lameter wrote: > > > I tinkered with some similar radical ideas lately. Maybe a bit vector > > could be used instead? For 1G of memory we would need > > > > 2^(30 - PAGE_SHIFT / 8 = 2^(30-12-3) = 2^15 = 32k bytes of a bitmap. > > > > Seems to be reasonable? > > At that point, wouldn't it be easier to simply increase > the size of struct page? I don't think they're power of > two sized anyway, at least on 64 bit architectures. That gives us an additional 32 bits in one hit whereas the external bitmap allows us to fine-tune it. Doing neither is of course best.. -- 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