From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 8 Aug 2007 10:57:13 -0700 (PDT) From: Christoph Lameter 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: owner-linux-mm@kvack.org Return-Path: 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 List-ID: 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, 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