Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964791AbWCNWMA (ORCPT ); Tue, 14 Mar 2006 17:12:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964795AbWCNWMA (ORCPT ); Tue, 14 Mar 2006 17:12:00 -0500 Received: from fmr17.intel.com ([134.134.136.16]:2188 "EHLO orsfmr002.jf.intel.com") by vger.kernel.org with ESMTP id S964791AbWCNWMA convert rfc822-to-8bit (ORCPT ); Tue, 14 Mar 2006 17:12:00 -0500 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT X-MimeOLE: Produced By Microsoft Exchange V6.5.7226.0 Subject: RE: [PATCH] provide hrtimer exports for module use [Was: Exports for hrtimer APIs] Date: Tue, 14 Mar 2006 14:11:44 -0800 Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [PATCH] provide hrtimer exports for module use [Was: Exports for hrtimer APIs] Thread-Index: AcZHr0cFtDO0p068SiapIBwj5obT7wAAblKw From: "Stone, Joshua I" To: "Andrew Morton" Cc: , "Thomas Gleixner" X-OriginalArrivalTime: 14 Mar 2006 22:11:46.0465 (UTC) FILETIME=[489E3110:01C647B4] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1585 Lines: 40 Andrew Morton wrote: > Wordwrapped... Yes, Outlook/Exchange betrayed me... sorry. > gee, that's a lot of exports. I don't know whether all of these > would be considered stable over the long-term? For that first patch, I simply looked for the functions that looked appropriate for general users of hrtimers. If you would like to be more conservative, these five are all I need for SystemTap: EXPORT_SYMBOL_GPL(ktime_add_ns); EXPORT_SYMBOL_GPL(hrtimer_forward); EXPORT_SYMBOL_GPL(hrtimer_start); EXPORT_SYMBOL_GPL(hrtimer_cancel); EXPORT_SYMBOL_GPL(hrtimer_init); > Can you tell us a bit about why systemtap modules need the hrtimer > capability? How it's being used and for what, etc? Sure - SystemTap uses timers to provide an asynchronous probe during module execution. This might be utilized for polling kernel states, for flushing trace data, and perhaps other similar uses. Currently we're using the main timer APIs - add_timer, mod_timer, etc. My motivation for moving to hrtimer is because of what I read in its documentation - basically that the timer wheel is best for timeout cases which are rarely recascaded. The way SystemTap uses timers is more for defining intervals, and they are always cascaded until the module is complete. The hrtimers seem more suited to this methodology. Correct me if I'm wrong... Josh - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/