Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946003Ab2KNXcq (ORCPT ); Wed, 14 Nov 2012 18:32:46 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:38583 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1945916Ab2KNXcp (ORCPT ); Wed, 14 Nov 2012 18:32:45 -0500 Date: Wed, 14 Nov 2012 15:32:43 -0800 From: Andrew Morton To: Alan Cox Cc: "Kirill A. Shutemov" , Andrea Arcangeli , linux-mm@kvack.org, Andi Kleen , "H. Peter Anvin" , linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: Re: [PATCH v5 00/11] Introduce huge zero page Message-Id: <20121114153243.0f6d6bec.akpm@linux-foundation.org> In-Reply-To: <20121114232013.7ee42414@pyramind.ukuu.org.uk> References: <1352300463-12627-1-git-send-email-kirill.shutemov@linux.intel.com> <20121114133342.cc7bcd6e.akpm@linux-foundation.org> <20121114232013.7ee42414@pyramind.ukuu.org.uk> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 848 Lines: 22 On Wed, 14 Nov 2012 23:20:13 +0000 Alan Cox wrote: > > I'm still a bit concerned over the possibility that some workloads will > > cause a high-frequency free/alloc/memset cycle on that huge zero page. > > We'll see how it goes... > > That is easy enough to fix - we can delay the freeing by a random time or > until memory pressure is applied. > The current code does the latter, by freeing the page via a "slab"-shrinker callback. But I do suspect that with the right combination of use/unuse and memory pressure, we could still get into the high-frequency scenario. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/