Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764772AbYB0IFm (ORCPT ); Wed, 27 Feb 2008 03:05:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763784AbYB0IFN (ORCPT ); Wed, 27 Feb 2008 03:05:13 -0500 Received: from rv-out-0910.google.com ([209.85.198.185]:33824 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757578AbYB0IFI (ORCPT ); Wed, 27 Feb 2008 03:05:08 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=QNGH44XSwE/Ol19NHTl/fCNu/jCKBg/2bRN8nPiQzVpsJ/VggQmh1t8YoYdxN98ZsM2ZdhmNNXZJxqpd78HU4BOlJ1SbRnaaYXhhlRZTf/aIIcctyn8GaiQjCVcXCkN7gAceXNHjZmCKH74MIu7bX3p+ndO+feMfK8eWnKBUzlc= Message-ID: <84144f020802270005p3bfbd04ar9da2875218ef98c4@mail.gmail.com> Date: Wed, 27 Feb 2008 10:05:04 +0200 From: "Pekka Enberg" To: "Peter Zijlstra" Subject: Re: [PATCH 00/28] Swap over NFS -v16 Cc: "Neil Brown" , "Andrew Morton" , "Linus Torvalds" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, trond.myklebust@fys.uio.no In-Reply-To: <1204099113.6242.353.camel@lappy> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080220144610.548202000@chello.nl> <20080223000620.7fee8ff8.akpm@linux-foundation.org> <18371.43950.150842.429997@notabene.brown> <1204023042.6242.271.camel@lappy> <18372.64081.995262.986841@notabene.brown> <1204099113.6242.353.camel@lappy> X-Google-Sender-Auth: 431c33bee954cbe9 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1072 Lines: 21 Hi Peter, On Wed, Feb 27, 2008 at 9:58 AM, Peter Zijlstra wrote: > > 1/ I note there is no way to tell if memory returned by kmalloc is > > from the emergency reserve - which contrasts with alloc_page > > which does make that information available through page->reserve. > > This seems a slightly unfortunate aspect of the interface. > > Yes, but alas there is no room to store such information in kmalloc(). > That is, in a sane way. I think it was Daniel Phillips who suggested > encoding it in the return pointer by flipping the low bit - but that is > just too ugly and breaks all current kmalloc sites to boot. Why can't you add a kmem_is_emergency() to SLUB that looks up the cache/slab/page (whatever is the smallest unit of the emergency pool here) for the object and use that? -- 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/