From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f175.google.com (mail-qk0-f175.google.com [209.85.220.175]) by kanga.kvack.org (Postfix) with ESMTP id 289456B00C6 for ; Mon, 18 May 2015 11:20:49 -0400 (EDT) Received: by qkgw4 with SMTP id w4so71174292qkg.3 for ; Mon, 18 May 2015 08:20:49 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id d7si8514425qka.121.2015.05.18.08.20.47 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 18 May 2015 08:20:48 -0700 (PDT) From: David Howells In-Reply-To: References: <7254.1431945085@warthog.procyon.org.uk> <23799.1431955741@warthog.procyon.org.uk> Subject: Re: [RFC] Refactor kenter/kleave/kdebug macros MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <28900.1431962436.1@warthog.procyon.org.uk> Date: Mon, 18 May 2015 16:20:36 +0100 Message-ID: <28901.1431962436@warthog.procyon.org.uk> Sender: owner-linux-mm@kvack.org List-ID: To: Leon Romanovsky Cc: dhowells@redhat.com, Linux-MM , "linux-kernel@vger.kernel.org" , linux-cachefs , linux-afs Leon Romanovsky wrote: > >> Additionally, It looks like the output of these macros can be viewed by > >> ftrace mechanism. > > > > *blink* It can? > I was under strong impression that "function" and "function_graph" > tracers will give similar kenter/kleave information. Do I miss > anything important, except the difference in output format? > > > > >> Maybe we should delete them from mm/nommu.c as was pointed by Joe? > > > > Why? > If ftrace is sufficient to get the debug information, there will no > need to duplicate it. It isn't sufficient. It doesn't store the parameters or the return value, it doesn't distinguish the return path in a function when there's more than one, eg.: kleave(" = %d [val]", ret); vs: kleave(" = %lx", result); in do_mmap_pgoff() and it doesn't permit you to retrieve data from where the argument pointers that you don't have pointed to, eg.: kenter("%p{%d}", region, region->vm_usage); David -- 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