From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx147.postini.com [74.125.245.147]) by kanga.kvack.org (Postfix) with SMTP id A982C6B010D for ; Mon, 11 Jun 2012 06:38:01 -0400 (EDT) Received: by obbwd18 with SMTP id wd18so8695934obb.14 for ; Mon, 11 Jun 2012 03:38:00 -0700 (PDT) Message-ID: <1339411150.4999.43.camel@lappy> Subject: Re: [PATCH v3 08/10] mm: frontswap: add tracing support From: Sasha Levin 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" Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: 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 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, 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