From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from westrelay02.boulder.ibm.com (westrelay02.boulder.ibm.com [9.17.195.11]) by e34.co.us.ibm.com (8.12.11/8.12.11) with ESMTP id jAIJX1Fg004157 for ; Fri, 18 Nov 2005 14:33:01 -0500 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by westrelay02.boulder.ibm.com (8.12.10/NCO/VERS6.8) with ESMTP id jAIJWjT9087340 for ; Fri, 18 Nov 2005 12:32:45 -0700 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11/8.13.3) with ESMTP id jAIJX0mg023580 for ; Fri, 18 Nov 2005 12:33:00 -0700 Message-ID: <437E2C69.4000708@us.ibm.com> Date: Fri, 18 Nov 2005 11:32:57 -0800 From: Matthew Dobson MIME-Version: 1.0 Subject: [RFC][PATCH 0/8] Critical Page Pool Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: linux-kernel@vger.kernel.org Cc: Linux Memory Management List-ID: We have a clustering product that needs to be able to guarantee that the networking system won't stop functioning in the case of OOM/low memory condition. The current mempool system is inadequate because to keep the whole networking stack functioning, we need more than 1 or 2 slab caches to be guaranteed. We need to guarantee that any request made with a specific flag will succeed, assuming of course that you've made your "critical page pool" big enough. The following patch series implements such a critical page pool. It creates 2 userspace triggers: /proc/sys/vm/critical_pages: write the number of pages you want to reserve for the critical pool into this file /proc/sys/vm/in_emergency: write a non-zero value to tell the kernel that the system is in an emergency state and authorize the kernel to dip into the critical pool to satisfy critical allocations. We mark critical allocations with the __GFP_CRITICAL flag, and when the system is in an emergency state, we are allowed to delve into this pool to satisfy __GFP_CRITICAL allocations that cannot be satisfied through the normal means. Feedback on our approach would be appreciated. Thanks! -Matt -- 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