Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935969AbXHHR51 (ORCPT ); Wed, 8 Aug 2007 13:57:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762760AbXHHR5Q (ORCPT ); Wed, 8 Aug 2007 13:57:16 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:38089 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1762506AbXHHR5Q (ORCPT ); Wed, 8 Aug 2007 13:57:16 -0400 Date: Wed, 8 Aug 2007 10:57:13 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Andrew Morton cc: Matt Mackall , Peter Zijlstra , linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Miller , Daniel Phillips , Pekka Enberg , Lee Schermerhorn , Steve Dickson Subject: Re: [PATCH 04/10] mm: slub: add knowledge of reserve pages In-Reply-To: <20070808103946.4cece16c.akpm@linux-foundation.org> Message-ID: References: <20070806102922.907530000@chello.nl> <20070806103658.603735000@chello.nl> <20070808014435.GG30556@waste.org> <20070808103946.4cece16c.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 982 Lines: 21 On Wed, 8 Aug 2007, Andrew Morton wrote: > 3. Perform page reclaim from hard IRQ context. Pretty simple to > implement, most of the work would be needed in the rmap code. It might be > better to make it opt-in via a new __GFP_flag. In a hardirq context one is bound to a processor and through the slab allocator to a slab from which one allocates objects. The slab is per cpu and so the slab is reserved for the current context. Nothing can take objects away from it. The modifications here would not be needed for that context. I think in general irq context reclaim is doable. Cannot see obvious issues on a first superficial pass through rmap.c. The irq holdoff would be pretty long though which may make it unacceptable. - 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/