From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 26 Apr 2013 21:46:33 +0200 From: Andi Kleen To: Peter Zijlstra Cc: Andi Kleen , mingo@kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, eranian@google.com, Andi Kleen Subject: Re: [PATCH 1/2] Fix perf LBR filtering Message-ID: <20130426194633.GF16732@two.firstfloor.org> References: <1366844694-2770-1-git-send-email-andi@firstfloor.org> <20130425162535.GA5828@dyad.programming.kicks-ass.net> <20130425164100.GC16732@two.firstfloor.org> <20130425164837.GD5828@dyad.programming.kicks-ass.net> <20130425170037.GD16732@two.firstfloor.org> <20130425171842.GA8669@dyad.programming.kicks-ass.net> <20130425174211.GE16732@two.firstfloor.org> <20130426075601.GB8669@dyad.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130426075601.GB8669@dyad.programming.kicks-ass.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: > > OK, so how about we use something like: > > is_kernel_text() || is_module_text_address() is_module_text_address() has to walk all modules. A random system with a distro kernel I checked has 101 modules loaded. 16 * 101 = too much I don't think you want to spend that many cycles in the NMI handler for a dubious feature. Ok in theory you could add something with binary search, but that would be quite a bit of effort and it would be probably challenging to do that all NMI safe. Also it wouldn't work for all these new kernel JITs people are doing of course. Still think my patch is the best so far? (plus the missing root check) -Andi -- ak@linux.intel.com -- Speaking for myself only.