From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [PATCH] Only process_die notifier in ia64_do_page_fault if KPROBES is configured. Date: Wed, 31 Aug 2005 01:38:08 +0200 References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200508310138.09841.ak@suse.de> Sender: owner-linux-mm@kvack.org Return-Path: To: "Luck, Tony" Cc: Christoph Lameter , Rusty Lynch , "Lynch, Rusty" , linux-mm@kvack.org, prasanna@in.ibm.com, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, "Keshavamurthy, Anil S" List-ID: On Wednesday 31 August 2005 01:05, Luck, Tony wrote: > >Please do not generate any code if the feature cannot ever be > >used (CONFIG_KPROBES off). With this patch we still have lots of > >unnecessary code being executed on each page fault. > > I can (eventually) wrap this call inside the #ifdef CONFIG_KPROBES. At least the original die notifiers were designed as a generic debugger interface, not a kprobes specific thing. So I don't think it's a good idea. Given most debuggers don't need the early page fault hook and it's mostly needed for a special case in kprobes, but it doesn't seem nice to only offer a subset of the hooks with specific config options. Also with the inline the test should be essentially a single test of a global variable and jump. Hardly a big performance issue, no? -Andi -- 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