From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David S. Miller" Subject: Re: [RFC][PATCH 0/3] TCP/IP Critical socket communication mechanism Date: Thu, 15 Dec 2005 00:21:20 -0800 (PST) Message-ID: <20051215.002120.133621586.davem@davemloft.net> References: <20051215033937.GC11856@waste.org> <20051214.203023.129054759.davem@davemloft.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: mpm@selenic.com, ak@suse.de, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Return-path: To: sri@us.ibm.com In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Sridhar Samudrala Date: Wed, 14 Dec 2005 23:37:37 -0800 (PST) > Instead, you seem to be suggesting in_emergency to be set dynamically > when we are about to run out of ATOMIC memory. Is this right? Not when we run out, but rather when we reach some low water mark, the "critical sockets" would still use GFP_ATOMIC memory but only "critical sockets" would be allowed to do so. But even this has faults, consider the IPSEC scenerio I mentioned, and this applies to any kind of encapsulation actually, even simple tunneling examples can be concocted which make the "critical socket" idea fail. The knee jerk reaction is "mark IPSEC's sockets critical, and mark the tunneling allocations critical, and... and..." well you have GFP_ATOMIC then my friend. In short, these "seperate page pool" and "critical socket" ideas do not work and we need a different solution, I'm sorry folks spent so much time on them, but they are heavily flawed.