Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753249Ab2FKKiE (ORCPT ); Mon, 11 Jun 2012 06:38:04 -0400 Received: from mail-ob0-f174.google.com ([209.85.214.174]:60117 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753088Ab2FKKiB (ORCPT ); Mon, 11 Jun 2012 06:38:01 -0400 Message-ID: <1339411150.4999.43.camel@lappy> Subject: Re: [PATCH v3 08/10] mm: frontswap: add tracing support From: Sasha Levin To: Pekka Enberg Cc: Minchan Kim , dan.magenheimer@oracle.com, konrad.wilk@oracle.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Steven Rostedt , Ingo Molnar Date: Mon, 11 Jun 2012 12:39:10 +0200 In-Reply-To: References: <1339325468-30614-1-git-send-email-levinsasha928@gmail.com> <1339325468-30614-9-git-send-email-levinsasha928@gmail.com> <4FD58C54.7050504@kernel.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1390 Lines: 32 On Mon, 2012-06-11 at 11:33 +0300, Pekka Enberg wrote: > On 06/10/2012 07:51 PM, Sasha Levin wrote: > >> Add tracepoints to frontswap API. > >> > >> Signed-off-by: Sasha Levin > > On Mon, Jun 11, 2012 at 9:12 AM, Minchan Kim wrote: > > Normally, adding new tracepoint isn't easy without special reason. > > I'm not sure all of frontswap function tracing would be valuable. > > Shsha, Why do you want to add tracing? > > What's scenario you want to use tracing? I added tracing when working on code to integrate KVM with frontswap/cleancache and needed to see that the flow of code between host side kvm and zcache and guest side cleancache, frontswap and kvm is correct. > Yup, the added tracepoints look more like function tracing. Shouldn't > you use something like kprobes or ftrace/perf for this? I'm not sure really, there are quite a few options provided by the kernel... I used tracepoints because I was working on code that integrates with KVM, and saw that KVM was working with tracepoints in a very similar way to what I needed, so I assumed tracepoints is the right choice for me. -- 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/