From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id B86906B01A5 for ; Thu, 14 May 2009 07:48:04 -0400 (EDT) Received: from eu_spt2 (mailout1.w1.samsung.com [210.118.77.11]) by mailout1.w1.samsung.com (iPlanet Messaging Server 5.2 Patch 2 (built Jul 14 2004)) with ESMTP id <0KJM00AJUU5BU3@mailout1.w1.samsung.com> for linux-mm@kvack.org; Thu, 14 May 2009 12:48:47 +0100 (BST) Received: from amdc030 ([106.116.37.122]) by spt2.w1.samsung.com (iPlanet Messaging Server 5.2 Patch 2 (built Jul 14 2004)) with ESMTPA id <0KJM00D7XU54YB@spt2.w1.samsung.com> for linux-mm@kvack.org; Thu, 14 May 2009 12:48:47 +0100 (BST) Date: Thu, 14 May 2009 13:48:39 +0200 From: =?utf-8?B?TWljaGHFgiBOYXphcmV3aWN6?= Subject: Re: [PATCH] Physical Memory Management [0/1] In-reply-to: <1242300002.6642.1091.camel@laptop> Message-id: MIME-version: 1.0 Content-type: text/plain; charset=utf-8 Content-transfer-encoding: 8BIT References: <20090513151142.5d166b92.akpm@linux-foundation.org> <1242300002.6642.1091.camel@laptop> Sender: owner-linux-mm@kvack.org To: Peter Zijlstra Cc: Andrew Morton , linux-kernel@vger.kernel.org, m.szyprowski@samsung.com, kyungmin.park@samsung.com, linux-mm@kvack.org List-ID: > On Thu, 2009-05-14 at 11:00 +0200, MichaA? Nazarewicz wrote: >> PMM solves this problem since the buffers are allocated when they >> are needed. On Thu, 14 May 2009 13:20:02 +0200, Peter Zijlstra wrote: > Ha - only when you actually manage to allocate things. Physically > contiguous allocations are exceedingly hard once the machine has been > running for a while. PMM reserves memory during boot time using alloc_bootmem_low_pages(). After this is done, it can allocate buffers from reserved pool. The idea here is that there are n hardware accelerators, each can operate on 1MiB blocks (to simplify assume that's the case). However, we know that at most m < n devices will be used at the same time so instead of reserving n MiBs of memory we reserve only m MiBs. -- Best regards, _ _ .o. | Liege of Serenly Enlightened Majesty of o' \,=./ `o ..o | Computer Science, MichaA? "mina86" Nazarewicz (o o) ooo +---ooO--(_)--Ooo-- -- 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